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	"title": "https://www.ietf.org/rfc/rfc4949.txt",
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	"plain_text": "https://www.ietf.org/rfc/rfc4949.txt\r\nArchived: 2026-04-05 18:56:54 UTC\r\nNetwork Working Group R. Shirey\r\nRequest for Comments: 4949 August 2007\r\nFYI: 36\r\nObsoletes: 2828\r\nCategory: Informational\r\n Internet Security Glossary, Version 2\r\nStatus of This Memo\r\n This memo provides information for the Internet community. It does\r\n not specify an Internet standard of any kind. Distribution of this\r\n memo is unlimited.\r\nCopyright Notice\r\n Copyright (C) The IETF Trust (2007).\r\nRFC Editor Note\r\n This document is both a major revision and a major expansion of the\r\n Security Glossary in RFC 2828. This revised Glossary is an extensive\r\n reference that should help the Internet community to improve the\r\n clarity of documentation and discussion in an important area of\r\n Internet technology. However, readers should be aware of the\r\n following:\r\n (1) The recommendations and some particular interpretations in\r\n definitions are those of the author, not an official IETF position.\r\n The IETF has not taken a formal position either for or against\r\n recommendations made by this Glossary, and the use of RFC 2119\r\n language (e.g., SHOULD NOT) in the Glossary must be understood as\r\n unofficial. In other words, the usage rules, wording interpretations,\r\n and other recommendations that the Glossary offers are personal\r\n opinions of the Glossary's author. Readers must judge for themselves\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 1 of 436\n\nwhether or not to follow his recommendations, based on their own\r\n knowledge combined with the reasoning presented in the Glossary.\r\n (2) The glossary is rich in the history of early network security\r\n work, but it may be somewhat incomplete in describing recent security\r\n work, which has been developing rapidly.\r\nShirey Informational [Page 1]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nAbstract\r\n This Glossary provides definitions, abbreviations, and explanations\r\n of terminology for information system security. The 334 pages of\r\n entries offer recommendations to improve the comprehensibility of\r\n written material that is generated in the Internet Standards Process\r\n (RFC 2026). The recommendations follow the principles that such\r\n writing should (a) use the same term or definition whenever the same\r\n concept is mentioned; (b) use terms in their plainest, dictionary\r\n sense; (c) use terms that are already well-established in open\r\n publications; and (d) avoid terms that either favor a particular\r\n vendor or favor a particular technology or mechanism over other,\r\n competing techniques that already exist or could be developed.\r\nTable of Contents\r\n 1. Introduction ....................................................3\r\n 2. Format of Entries ...............................................4\r\n 2.1. Order of Entries ...........................................4\r\n 2.2. Capitalization and Abbreviations ...........................5\r\n 2.3. Support for Automated Searching ............................5\r\n 2.4. Definition Type and Context ................................5\r\n 2.5. Explanatory Notes ..........................................6\r\n 2.6. Cross-References ...........................................6\r\n 2.7. Trademarks .................................................6\r\n 2.8. The New Punctuation ........................................6\r\n 3. Types of Entries ................................................7\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 2 of 436\n\n3.1. Type \"I\": Recommended Definitions of Internet Origin .......7\r\n 3.2. Type \"N\": Recommended Definitions of Non-Internet Origin ...8\r\n 3.3. Type \"O\": Other Terms and Definitions To Be Noted ..........8\r\n 3.4. Type \"D\": Deprecated Terms and Definitions .................8\r\n 3.5. Definition Substitutions ...................................8\r\n 4. Definitions .....................................................9\r\n 5. Security Considerations .......................................343\r\n 6. Normative Reference ...........................................343\r\n 7. Informative References ........................................343\r\n 8. Acknowledgments ...............................................364\r\nShirey Informational [Page 2]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n1. Introduction\r\n This Glossary is *not* an Internet Standard, and its recommendations\r\n represent only the opinions of its author. However, this Glossary\r\n gives reasons for its recommendations -- especially for the SHOULD\r\n NOTs -- so that readers can judge for themselves what to do.\r\n This Glossary provides an internally consistent and self-contained\r\n set of terms, abbreviations, and definitions -- supported by\r\n explanations, recommendations, and references -- for terminology that\r\n concerns information system security. The intent of this Glossary is\r\n to improve the comprehensibility of written materials that are\r\n generated in the Internet Standards Process (RFC 2026) -- i.e., RFCs,\r\n Internet-Drafts, and other items of discourse -- which are referred\r\n to here as IDOCs. A few non-security, networking terms are included\r\n to make the Glossary self-contained, but more complete glossaries of\r\n such terms are available elsewhere [A1523, F1037, R1208, R1983].\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 3 of 436\n\nThis Glossary supports the goals of the Internet Standards Process:\r\n o Clear, Concise, Easily Understood Documentation\r\n This Glossary seeks to improve comprehensibility of security-\r\n related content of IDOCs. That requires wording to be clear and\r\n understandable, and requires the set of security-related terms and\r\n definitions to be consistent and self-supporting. Also,\r\n terminology needs to be uniform across all IDOCs; i.e., the same\r\n term or definition needs to be used whenever and wherever the same\r\n concept is mentioned. Harmonization of existing IDOCs need not be\r\n done immediately, but it is desirable to correct and standardize\r\n terminology when new versions are issued in the normal course of\r\n standards development and evolution.\r\n o Technical Excellence\r\n Just as Internet Standard (STD) protocols should operate\r\n effectively, IDOCs should use terminology accurately, precisely,\r\n and unambiguously to enable standards to be implemented correctly.\r\n o Prior Implementation and Testing\r\n Just as STD protocols require demonstrated experience and\r\n stability before adoption, IDOCs need to use well-established\r\n language; and the robustness principle for protocols -- \"be\r\n liberal in what you accept, and conservative in what you send\" --\r\n is also applicable to the language used in IDOCs that describe\r\n protocols. Using terms in their plainest, dictionary sense (when\r\n appropriate) helps to make them more easily understood by\r\nShirey Informational [Page 3]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n international readers. IDOCs need to avoid using private, newly\r\n invented terms in place of generally accepted terms from open\r\n publications. IDOCs need to avoid substituting new definitions\r\n that conflict with established ones. IDOCs need to avoid using\r\n \"cute\" synonyms (e.g., \"Green Book\"), because no matter how\r\n popular a nickname may be in one community, it is likely to cause\r\n confusion in another.\r\n However, although this Glossary strives for plain, internationally\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 4 of 436\n\nunderstood English language, its terms and definitions are biased\r\n toward English as used in the United States of America (U.S.).\r\n Also, with regard to terminology used by national governments and\r\n in national defense areas, the glossary addresses only U.S. usage.\r\n o Openness, Fairness, and Timeliness\r\n IDOCs need to avoid using proprietary and trademarked terms for\r\n purposes other than referring to those particular systems. IDOCs\r\n also need to avoid terms that either favor a particular vendor or\r\n favor a particular security technology or mechanism over other,\r\n competing techniques that already exist or might be developed in\r\n the future. The set of terminology used across the set of IDOCs\r\n needs to be flexible and adaptable as the state of Internet\r\n security art evolves.\r\n In support of those goals, this Glossary offers guidance by marking\r\n terms and definitions as being either endorsed or deprecated for use\r\n in IDOCs. The key words \"SHOULD\", \"SHOULD NOT\", \"RECOMMENDED\", \"MAY\",\r\n and \"OPTIONAL\" are intended to be interpreted the same way as in an\r\n Internet Standard (i.e., as specified in RFC 2119 [R2119]). Other\r\n glossaries (e.g., [Raym]) list additional terms that deal with\r\n Internet security but have not been included in this Glossary because\r\n they are not appropriate for IDOCs.\r\n2. Format of Entries\r\n Section 4 presents Glossary entries in the following manner:\r\n2.1. Order of Entries\r\n Entries are sorted in lexicographic order, without regard to\r\n capitalization. Numeric digits are treated as preceding alphabetic\r\n characters, and special characters are treated as preceding digits.\r\n Blanks are treated as preceding non-blank characters, except that a\r\n hyphen or slash between the parts of a multiword entry (e.g.,\r\n \"RED/BLACK separation\") is treated like a blank.\r\nShirey Informational [Page 4]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 5 of 436\n\nIf an entry has multiple definitions (e.g., \"domain\"), they are\r\n numbered beginning with \"1\", and any of those multiple definitions\r\n that are RECOMMENDED for use in IDOCs are presented before other\r\n definitions for that entry. If definitions are closely related (e.g.,\r\n \"threat\"), they are denoted by adding letters to a number, such as\r\n \"1a\" and \"1b\".\r\n2.2. Capitalization and Abbreviations\r\n Entries that are proper nouns are capitalized (e.g., \"Data Encryption\r\n Algorithm\"), as are other words derived from proper nouns (e.g.,\r\n \"Caesar cipher\"). All other entries are not capitalized (e.g.,\r\n \"certification authority\"). Each acronym or other abbreviation that\r\n appears in this Glossary, either as an entry or in a definition or\r\n explanation, is defined in this Glossary, except items of common\r\n English usage, such as \"a.k.a.\", \"e.g.\", \"etc.\", \"i.e.\", \"vol.\",\r\n \"pp.\", and \"U.S.\".\r\n2.3. Support for Automated Searching\r\n Each entry is preceded by a dollar sign ($) and a space. This makes\r\n it possible to find the defining entry for an item \"X\" by searching\r\n for the character string \"$ X\", without stopping at other entries in\r\n which \"X\" is used in explanations.\r\n2.4. Definition Type and Context\r\n Each entry is preceded by a character -- I, N, O, or D -- enclosed in\r\n parentheses, to indicate the type of definition (as is explained\r\n further in Section 3):\r\n - \"I\" for a RECOMMENDED term or definition of Internet origin.\r\n - \"N\" if RECOMMENDED but not of Internet origin.\r\n - \"O\" for a term or definition that is NOT recommended for use in\r\n IDOCs but is something that authors of Internet documents should\r\n know about.\r\n - \"D\" for a term or definition that is deprecated and SHOULD NOT be\r\n used in Internet documents.\r\n If a definition is valid only in a specific context (e.g.,\r\n \"baggage\"), that context is shown immediately following the\r\n definition type and is enclosed by a pair of slash symbols (/). If\r\n the definition is valid only for specific parts of speech, that is\r\n shown in the same way (e.g., \"archive\").\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 6 of 436\n\nShirey Informational [Page 5]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n2.5. Explanatory Notes\r\n Some entries have explanatory text that is introduced by one or more\r\n of the following keywords:\r\n - Deprecated Abbreviation (e.g., \"AA\")\r\n - Deprecated Definition (e.g., \"digital certification\")\r\n - Deprecated Usage (e.g., \"authenticate\")\r\n - Deprecated Term (e.g., \"certificate authority\")\r\n - Pronunciation (e.g., \"*-property\")\r\n - Derivation (e.g., \"discretionary access control\")\r\n - Tutorial (e.g., \"accreditation\")\r\n - Example (e.g., \"back door\")\r\n - Usage (e.g., \"access\")\r\n Explanatory text in this Glossary MAY be reused in IDOCs. However,\r\n this text is not intended to authoritatively supersede text of an\r\n IDOC in which the Glossary entry is already used.\r\n2.6. Cross-References\r\n Some entries contain a parenthetical remark of the form \"(See: X.)\",\r\n where X is a list of other, related terms. Some entries contain a\r\n remark of the form \"(Compare: X)\", where X is a list of terms that\r\n either are antonyms of the entry or differ in some other manner worth\r\n noting.\r\n2.7. Trademarks\r\n All servicemarks and trademarks that appear in this Glossary are used\r\n in an editorial fashion and to the benefit of the mark owner, without\r\n any intention of infringement.\r\n2.8. The New Punctuation\r\n This Glossary uses the \"new\" or \"logical\" punctuation style favored\r\n by computer programmers, as described by Raymond [Raym]: Programmers\r\n use pairs of quotation marks the same way they use pairs of\r\n parentheses, i.e., as balanced delimiters. For example, if \"Alice\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 7 of 436\n\nsends\" is a phrase, and so are \"Bill receives\" and \"Eve listens\",\r\n then a programmer would write the following sentence:\r\n \"Alice sends\", \"Bill receives\", and \"Eve listens\".\r\n According to standard American usage, the punctuation in that\r\n sentence is incorrect; the continuation commas and the final period\r\n should go inside the string quotes, like this:\r\n \"Alice sends,\" \"Bill receives,\" and \"Eve listens.\"\r\nShirey Informational [Page 6]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n However, a programmer would not include a character in a literal\r\n string if the character did not belong there, because that could\r\n cause an error. For example, suppose a sentence in a draft of a\r\n tutorial on the vi editing language looked like this:\r\n Then delete one line from the file by typing \"dd\".\r\n A book editor following standard usage might change the sentence to\r\n look like this:\r\n Then delete one line from the file by typing \"dd.\"\r\n However, in the vi language, the dot character repeats the last\r\n command accepted. So, if a reader entered \"dd.\", two lines would be\r\n deleted instead of one.\r\n Similarly, use of standard American punctuation might cause\r\n misunderstanding in entries in this Glossary. Thus, the new\r\n punctuation is used here, and we recommend it for IDOCs.\r\n3. Types of Entries\r\n Each entry in this Glossary is marked as type I, N, O, or D:\r\n3.1. Type \"I\": Recommended Definitions of Internet Origin\r\n The marking \"I\" indicates two things:\r\n - Origin: \"I\" (as opposed to \"N\") means either that the Internet\r\n Standards Process or Internet community is authoritative for the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 8 of 436\n\ndefinition *or* that the term is sufficiently generic that this\r\n Glossary can freely state a definition without contradicting a\r\n non-Internet authority (e.g., \"attack\").\r\n - Recommendation: \"I\" (as opposed to \"O\") means that the term and\r\n definition are RECOMMENDED for use in IDOCs. However, some \"I\"\r\n entries may be accompanied by a \"Usage\" note that states a\r\n limitation (e.g., \"certification\"), and IDOCs SHOULD NOT use the\r\n defined term outside that limited context.\r\n Many \"I\" entries are proper nouns (e.g., \"Internet Protocol\") for\r\n which the definition is intended only to provide basic information;\r\n i.e., the authoritative definition of such terms is found elsewhere.\r\n For a proper noun described as an \"Internet protocol\", please refer\r\n to the current edition of \"Internet Official Protocol Standards\"\r\n (Standard 1) for the standardization status of the protocol.\r\nShirey Informational [Page 7]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n3.2. Type \"N\": Recommended Definitions of Non-Internet Origin\r\n The marking \"N\" indicates two things:\r\n - Origin: \"N\" (as opposed to \"I\") means that the entry has a non-\r\n Internet basis or origin.\r\n - Recommendation: \"N\" (as opposed to \"O\") means that the term and\r\n definition are RECOMMENDED for use in IDOCs, if they are needed at\r\n all in IDOCs. Many of these entries are accompanied by a label\r\n that states a context (e.g., \"package\") or a note that states a\r\n limitation (e.g., \"data integrity\"), and IDOCs SHOULD NOT use the\r\n defined term outside that context or limit. Some of the contexts\r\n are rarely if ever expected to occur in an IDOC (e.g., \"baggage\").\r\n In those cases, the listing exists to make Internet authors aware\r\n of the non-Internet usage so that they can avoid conflicts with\r\n non-Internet documents.\r\n3.3. Type \"O\": Other Terms and Definitions To Be Noted\r\n The marking \"O\" means that the definition is of non-Internet origin\r\n and SHOULD NOT be used in IDOCs *except* in cases where the term is\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 9 of 436\n\nspecifically identified as non-Internet.\r\n For example, an IDOC might mention \"BCA\" (see: brand certification\r\n authority) or \"baggage\" as an example of some concept; in that case,\r\n the document should specifically say \"SET(trademark) BCA\" or\r\n \"SET(trademark) baggage\" and include the definition of the term.\r\n3.4. Type \"D\": Deprecated Terms and Definitions\r\n If this Glossary recommends that a term or definition SHOULD NOT be\r\n used in IDOCs, then the entry is marked as type \"D\", and an\r\n explanatory note -- \"Deprecated Term\", \"Deprecated Abbreviation\",\r\n \"Deprecated Definition\", or \"Deprecated Usage\" -- is provided.\r\n3.5. Definition Substitutions\r\n Some terms have a definition published by a non-Internet authority --\r\n a government (e.g., \"object reuse\"), an industry (e.g., \"Secure Data\r\n Exchange\"), a national authority (e.g., \"Data Encryption Standard\"),\r\n or an international body (e.g., \"data confidentiality\") -- that is\r\n suitable for use in IDOCs. In those cases, this Glossary marks the\r\n definition \"N\", recommending its use in Internet documents.\r\n Other such terms have definitions that are inadequate or\r\n inappropriate for IDOCs. For example, a definition might be outdated\r\n or too narrow, or it might need clarification by substituting more\r\n careful wording (e.g., \"authentication exchange\") or explanations,\r\n using other terms that are defined in this Glossary. In those cases,\r\nShirey Informational [Page 8]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n this Glossary marks the entry \"O\", and provides an \"I\" or \"N\" entry\r\n that precedes, and is intended to supersede, the \"O\" entry.\r\n In some cases where this Glossary provides a definition to supersede\r\n an \"O\" definition, the substitute is intended to subsume the meaning\r\n of the \"O\" entry and not conflict with it. For the term \"security\r\n service\", for example, the \"O\" definition deals narrowly with only\r\n communication services provided by layers in the OSIRM and is\r\n inadequate for the full range of IDOC usage, while the new \"I\"\r\n definition provided by this Glossary can be used in more situations\r\n and for more kinds of service. However, the \"O\" definition is also\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 10 of 436\n\nlisted so that IDOC authors will be aware of the context in which the\r\n term is used more narrowly.\r\n When making substitutions, this Glossary attempts to avoid\r\n contradicting any non-Internet authority. Still, terminology differs\r\n between authorities such as the American Bar Association, OSI, SET,\r\n the U.S. DoD, and other authorities; and this Glossary probably is\r\n not exactly aligned with any of them.\r\n4. Definitions\r\n $ *-property\r\n (N) Synonym for \"confinement property\" in the context of the Bell-\r\n LaPadula model. Pronunciation: star property.\r\n $ 3DES\r\n (N) See: Triple Data Encryption Algorithm.\r\n $ A1 computer system\r\n (O) /TCSEC/ See: Tutorial under \"Trusted Computer System\r\n Evaluation Criteria\". (Compare: beyond A1.)\r\n $ AA\r\n (D) See: Deprecated Usage under \"attribute authority\".\r\n $ ABA Guidelines\r\n (N) \"American Bar Association (ABA) Digital Signature Guidelines\"\r\n [DSG], a framework of legal principles for using digital\r\n signatures and digital certificates in electronic commerce.\r\n $ Abstract Syntax Notation One (ASN.1)\r\n (N) A standard for describing data objects. [Larm, X680] (See:\r\n CMS.)\r\n Usage: IDOCs SHOULD use the term \"ASN.1\" narrowly to describe the\r\n notation or language called \"Abstract Syntax Notation One\". IDOCs\r\n MAY use the term more broadly to encompass the notation, its\r\nShirey Informational [Page 9]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n associated encoding rules (see: BER), and software tools that\r\n assist in its use, when the context makes this meaning clear.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 11 of 436\n\nTutorial: OSIRM defines computer network functionality in layers.\r\n Protocols and data objects at higher layers are abstractly defined\r\n to be implemented using protocols and data objects from lower\r\n layers. A higher layer may define transfers of abstract objects\r\n between computers, and a lower layer may define those transfers\r\n concretely as strings of bits. Syntax is needed to specify data\r\n formats of abstract objects, and encoding rules are needed to\r\n transform abstract objects into bit strings at lower layers. OSI\r\n standards use ASN.1 for those specifications and use various\r\n encoding rules for those transformations. (See: BER.)\r\n In ASN.1, formal names are written without spaces, and separate\r\n words in a name are indicated by capitalizing the first letter of\r\n each word except the first word. For example, the name of a CRL is\r\n \"certificateRevocationList\".\r\n $ ACC\r\n (I) See: access control center.\r\n $ acceptable risk\r\n (I) A risk that is understood and tolerated by a system's user,\r\n operator, owner, or accreditor, usually because the cost or\r\n difficulty of implementing an effective countermeasure for the\r\n associated vulnerability exceeds the expectation of loss. (See:\r\n adequate security, risk, \"second law\" under \"Courtney's laws\".)\r\n $ access\r\n 1a. (I) The ability and means to communicate with or otherwise\r\n interact with a system to use system resources either to handle\r\n information or to gain knowledge of the information the system\r\n contains. (Compare: handle.)\r\n Usage: The definition is intended to include all types of\r\n communication with a system, including one-way communication in\r\n either direction. In actual practice, however, passive users might\r\n be treated as not having \"access\" and, therefore, be exempt from\r\n most requirements of the system's security policy. (See: \"passive\r\n user\" under \"user\".)\r\n 1b. (O) \"Opportunity to make use of an information system (IS)\r\n resource.\" [C4009]\r\n 2. (O) /formal model/ \"A specific type of interaction between a\r\n subject and an object that results in the flow of information from\r\n one to the other.\" [NCS04]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 12 of 436\n\nShirey Informational [Page 10]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Access Certificate for Electronic Services (ACES)\r\n (O) A PKI operated by the U.S. Government's General Services\r\n Administration in cooperation with industry partners. (See: CAM.)\r\n $ access control\r\n 1. (I) Protection of system resources against unauthorized access.\r\n 2. (I) A process by which use of system resources is regulated\r\n according to a security policy and is permitted only by authorized\r\n entities (users, programs, processes, or other systems) according\r\n to that policy. (See: access, access control service, computer\r\n security, discretionary access control, mandatory access control,\r\n role-based access control.)\r\n 3. (I) /formal model/ Limitations on interactions between subjects\r\n and objects in an information system.\r\n 4. (O) \"The prevention of unauthorized use of a resource,\r\n including the prevention of use of a resource in an unauthorized\r\n manner.\" [I7498-2]\r\n 5. (O) /U.S. Government/ A system using physical, electronic, or\r\n human controls to identify or admit personnel with properly\r\n authorized access to a SCIF.\r\n $ access control center (ACC)\r\n (I) A computer that maintains a database (possibly in the form of\r\n an access control matrix) defining the security policy for an\r\n access control service, and that acts as a server for clients\r\n requesting access control decisions.\r\n Tutorial: An ACC is sometimes used in conjunction with a key\r\n center to implement access control in a key-distribution system\r\n for symmetric cryptography. (See: BLACKER, Kerberos.)\r\n $ access control list (ACL)\r\n (I) /information system/ A mechanism that implements access\r\n control for a system resource by enumerating the system entities\r\n that are permitted to access the resource and stating, either\r\n implicitly or explicitly, the access modes granted to each entity.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 13 of 436\n\n(Compare: access control matrix, access list, access profile,\r\n capability list.)\r\n $ access control matrix\r\n (I) A rectangular array of cells, with one row per subject and one\r\n column per object. The entry in a cell -- that is, the entry for a\r\n particular subject-object pair -- indicates the access mode that\r\n the subject is permitted to exercise on the object. Each column is\r\nShirey Informational [Page 11]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n equivalent to an \"access control list\" for the object; and each\r\n row is equivalent to an \"access profile\" for the subject.\r\n $ access control service\r\n (I) A security service that protects against a system entity using\r\n a system resource in a way not authorized by the system's security\r\n policy. (See: access control, discretionary access control,\r\n identity-based security policy, mandatory access control, rule-\r\n based security policy.)\r\n Tutorial: This service includes protecting against use of a\r\n resource in an unauthorized manner by an entity (i.e., a\r\n principal) that is authorized to use the resource in some other\r\n manner. (See: insider.) The two basic mechanisms for implementing\r\n this service are ACLs and tickets.\r\n $ access level\r\n 1. (D) Synonym for the hierarchical \"classification level\" in a\r\n security level. [C4009] (See: security level.)\r\n 2. (D) Synonym for \"clearance level\".\r\n Deprecated Definitions: IDOCs SHOULD NOT use this term with these\r\n definitions because they duplicate the meaning of more specific\r\n terms. Any IDOC that uses this term SHOULD provide a specific\r\n definition for it because access control may be based on many\r\n attributes other than classification level and clearance level.\r\n $ access list\r\n (I) /physical security/ Roster of persons who are authorized to\r\n enter a controlled area. (Compare: access control list.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 14 of 436\n\n$ access mode\r\n (I) A distinct type of data processing operation (e.g., read,\r\n write, append, or execute, or a combination of operations) that a\r\n subject can potentially perform on an object in an information\r\n system. [Huff] (See: read, write.)\r\n $ access policy\r\n (I) A kind of \"security policy\". (See: access, access control.)\r\n $ access profile\r\n (O) Synonym for \"capability list\".\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the definition is not widely known.\r\nShirey Informational [Page 12]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ access right\r\n (I) Synonym for \"authorization\"; emphasizes the possession of the\r\n authorization by a system entity.\r\n $ accountability\r\n (I) The property of a system or system resource that ensures that\r\n the actions of a system entity may be traced uniquely to that\r\n entity, which can then be held responsible for its actions. [Huff]\r\n (See: audit service.)\r\n Tutorial: Accountability (a.k.a. individual accountability)\r\n typically requires a system ability to positively associate the\r\n identity of a user with the time, method, and mode of the user's\r\n access to the system. This ability supports detection and\r\n subsequent investigation of security breaches. Individual persons\r\n who are system users are held accountable for their actions after\r\n being notified of the rules of behavior for using the system and\r\n the penalties associated with violating those rules.\r\n $ accounting See: COMSEC accounting.\r\n $ accounting legend code (ALC)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 15 of 436\n\n(O) /U.S. Government/ Numeric system used to indicate the minimum\r\n accounting controls required for items of COMSEC material within\r\n the CMCS. [C4009] (See: COMSEC accounting.)\r\n $ accreditation\r\n (N) An administrative action by which a designated authority\r\n declares that an information system is approved to operate in a\r\n particular security configuration with a prescribed set of\r\n safeguards. [FP102, SP37] (See: certification.)\r\n Tutorial: An accreditation is usually based on a technical\r\n certification of the system's security mechanisms. To accredit a\r\n system, the approving authority must determine that any residual\r\n risk is an acceptable risk. Although the terms \"certification\" and\r\n \"accreditation\" are used more in the U.S. DoD and other U.S.\r\n Government agencies than in commercial organizations, the concepts\r\n apply any place where managers are required to deal with and\r\n accept responsibility for security risks. For example, the\r\n American Bar Association is developing accreditation criteria for\r\n CAs.\r\n $ accreditation boundary\r\n (O) Synonym for \"security perimeter\". [C4009]\r\nShirey Informational [Page 13]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ accreditor\r\n (N) A management official who has been designated to have the\r\n formal authority to \"accredit\" an information system, i.e., to\r\n authorize the operation of, and the processing of sensitive data\r\n in, the system and to accept the residual risk associated with the\r\n system. (See: accreditation, residual risk.)\r\n $ ACES\r\n (O) See: Access Certificate for Electronic Services.\r\n $ ACL\r\n (I) See: access control list.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 16 of 436\n\n$ acquirer\r\n 1. (O) /SET/ \"The financial institution that establishes an\r\n account with a merchant and processes payment card authorizations\r\n and payments.\" [SET1]\r\n 2. (O) /SET/ \"The institution (or its agent) that acquires from\r\n the card acceptor the financial data relating to the transaction\r\n and initiates that data into an interchange system.\" [SET2]\r\n $ activation data\r\n (N) Secret data, other than keys, that is required to access a\r\n cryptographic module. (See: CIK. Compare: initialization value.)\r\n $ active attack\r\n (I) See: secondary definition under \"attack\".\r\n $ active content\r\n 1a. (I) Executable software that is bound to a document or other\r\n data file and that executes automatically when a user accesses the\r\n file, without explicit initiation by the user. (Compare: mobile\r\n code.)\r\n Tutorial: Active content can be mobile code when its associated\r\n file is transferred across a network.\r\n 1b. (O) \"Electronic documents that can carry out or trigger\r\n actions automatically on a computer platform without the\r\n intervention of a user. [This technology enables] mobile code\r\n associated with a document to execute as the document is\r\n rendered.\" [SP28]\r\n $ active user\r\n (I) See: secondary definition under \"system user\".\r\nShirey Informational [Page 14]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ active wiretapping\r\n (I) A wiretapping attack that attempts to alter data being\r\n communicated or otherwise affect data flow. (See: wiretapping.\r\n Compare: active attack, passive wiretapping.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 17 of 436\n\n$ add-on security\r\n (N) The retrofitting of protection mechanisms, implemented by\r\n hardware or software, in an information system after the system\r\n has become operational. [FP039] (Compare: baked-in security.)\r\n $ adequate security\r\n (O) /U.S. DoD/ \"Security commensurate with the risk and magnitude\r\n of harm resulting from the loss, misuse, or unauthorized access to\r\n or modification of information.\" (See: acceptable risk, residual\r\n risk.)\r\n $ administrative security\r\n 1. (I) Management procedures and constraints to prevent\r\n unauthorized access to a system. (See: \"third law\" under\r\n \"Courtney's laws\", manager, operational security, procedural\r\n security, security architecture. Compare: technical security.)\r\n Examples: Clear delineation and separation of duties;\r\n configuration control.\r\n Usage: Administrative security is usually understood to consist of\r\n methods and mechanisms that are implemented and executed primarily\r\n by people, rather than by automated systems.\r\n 2. (O) \"The management constraints, operational procedures,\r\n accountability procedures, and supplemental controls established\r\n to provide an acceptable level of protection for sensitive data.\"\r\n [FP039]\r\n $ administrator\r\n 1. (O) /Common Criteria/ A person that is responsible for\r\n configuring, maintaining, and administering the TOE in a correct\r\n manner for maximum security. (See: administrative security.)\r\n 2. (O) /ITSEC/ A person in contact with the TOE, who is\r\n responsible for maintaining its operational capability.\r\n $ Advanced Encryption Standard (AES)\r\n (N) A U.S. Government standard [FP197] (the successor to DES) that\r\n (a) specifies \"the AES algorithm\", which is a symmetric block\r\n cipher that is based on Rijndael and uses key sizes of 128, 192,\r\n or 256 bits to operate on a 128-bit block, and (b) states policy\r\n for using that algorithm to protect unclassified, sensitive data.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 18 of 436\n\nShirey Informational [Page 15]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Rijndael was designed to handle additional block sizes\r\n and key lengths that were not adopted in the AES. Rijndael was\r\n selected by NIST through a public competition that was held to\r\n find a successor to the DEA; the other finalists were MARS, RC6,\r\n Serpent, and Twofish.\r\n $ adversary\r\n 1. (I) An entity that attacks a system. (Compare: cracker,\r\n intruder, hacker.)\r\n 2. (I) An entity that is a threat to a system.\r\n $ AES\r\n (N) See: Advanced Encryption Standard.\r\n $ Affirm\r\n (O) A formal methodology, language, and integrated set of software\r\n tools developed at the University of Southern California's\r\n Information Sciences Institute for specifying, coding, and\r\n verifying software to produce correct and reliable programs.\r\n [Cheh]\r\n $ aggregation\r\n (I) A circumstance in which a collection of information items is\r\n required to be classified at a higher security level than any of\r\n the items is classified individually. (See: classification.)\r\n $ AH\r\n (I) See: Authentication Header\r\n $ air gap\r\n (I) An interface between two systems at which (a) they are not\r\n connected physically and (b) any logical connection is not\r\n automated (i.e., data is transferred through the interface only\r\n manually, under human control). (See: sneaker net. Compare:\r\n gateway.)\r\n Example: Computer A and computer B are on opposite sides of a\r\n room. To move data from A to B, a person carries a disk across the\r\n room. If A and B operate in different security domains, then\r\n moving data across the air gap may involve an upgrade or downgrade\r\n operation.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 19 of 436\n\n$ ALC\r\n (O) See: accounting legend code.\r\nShirey Informational [Page 16]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ algorithm\r\n (I) A finite set of step-by-step instructions for a problem-\r\n solving or computation procedure, especially one that can be\r\n implemented by a computer. (See: cryptographic algorithm.)\r\n $ alias\r\n (I) A name that an entity uses in place of its real name, usually\r\n for the purpose of either anonymity or masquerade.\r\n $ Alice and Bob\r\n (I) The parties that are most often called upon to illustrate the\r\n operation of bipartite security protocols. These and other\r\n dramatis personae are listed by Schneier [Schn].\r\n $ American National Standards Institute (ANSI)\r\n (N) A private, not-for-profit association that administers U.S.\r\n private-sector voluntary standards.\r\n Tutorial: ANSI has approximately 1,000 member organizations,\r\n including equipment users, manufacturers, and others. These\r\n include commercial firms, governmental agencies, and other\r\n institutions and international entities.\r\n ANSI is the sole U.S. representative to (a) ISO and (b) (via the\r\n U.S. National Committee) the International Electrotechnical\r\n Commission (IEC), which are the two major, non-treaty,\r\n international standards organizations.\r\n ANSI provides a forum for ANSI-accredited standards development\r\n groups. Among those groups, the following are especially relevant\r\n to Internet security:\r\n - International Committee for Information Technology\r\n Standardization (INCITS) (formerly X3): Primary U.S. focus of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 20 of 436\n\nstandardization in information and communications technologies,\r\n encompassing storage, processing, transfer, display,\r\n management, organization, and retrieval of information.\r\n Example: [A3092].\r\n - Accredited Standards Committee X9: Develops, establishes,\r\n maintains, and promotes standards for the financial services\r\n industry. Example: [A9009].\r\n - Alliance for Telecommunications Industry Solutions (ATIS):\r\n Develops standards, specifications, guidelines, requirements,\r\n technical reports, industry processes, and verification tests\r\n for interoperability and reliability of telecommunications\r\n networks, equipment, and software. Example: [A1523].\r\nShirey Informational [Page 17]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ American Standard Code for Information Interchange (ASCII)\r\n (N) A scheme that encodes 128 specified characters -- the numbers\r\n 0-9, the letters a-z and A-Z, some basic punctuation symbols, some\r\n control codes that originated with Teletype machines, and a blank\r\n space -- into the 7-bit binary integers. Forms the basis of the\r\n character set representations used in most computers and many\r\n Internet standards. [FP001] (See: code.)\r\n $ Anderson report\r\n (O) A 1972 study of computer security that was written by James P.\r\n Anderson for the U.S. Air Force [Ande].\r\n Tutorial: Anderson collaborated with a panel of experts to study\r\n Air Force requirements for multilevel security. The study\r\n recommended research and development that was urgently needed to\r\n provide secure information processing for command and control\r\n systems and support systems. The report introduced the reference\r\n monitor concept and provided development impetus for computer and\r\n network security technology. However, many of the security\r\n problems that the 1972 report called \"current\" still plague\r\n information systems today.\r\n $ anomaly detection\r\n (I) An intrusion detection method that searches for activity that\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 21 of 436\n\nis different from the normal behavior of system entities and\r\n system resources. (See: IDS. Compare: misuse detection.)\r\n $ anonymity\r\n (I) The condition of an identity being unknown or concealed. (See:\r\n alias, anonymizer, anonymous credential, anonymous login,\r\n identity, onion routing, persona certificate. Compare: privacy.)\r\n Tutorial: An application may require security services that\r\n maintain anonymity of users or other system entities, perhaps to\r\n preserve their privacy or hide them from attack. To hide an\r\n entity's real name, an alias may be used; for example, a financial\r\n institution may assign account numbers. Parties to transactions\r\n can thus remain relatively anonymous, but can also accept the\r\n transactions as legitimate. Real names of the parties cannot be\r\n easily determined by observers of the transactions, but an\r\n authorized third party may be able to map an alias to a real name,\r\n such as by presenting the institution with a court order. In other\r\n applications, anonymous entities may be completely untraceable.\r\n $ anonymizer\r\n (I) An internetwork service, usually provided via a proxy server,\r\n that provides anonymity and privacy for clients. That is, the\r\n service enables a client to access servers (a) without allowing\r\nShirey Informational [Page 18]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n anyone to gather information about which servers the client\r\n accesses and (b) without allowing the accessed servers to gather\r\n information about the client, such as its IP address.\r\n $ anonymous credential\r\n (D) /U.S. Government/ A credential that (a) can be used to\r\n authenticate a person as having a specific attribute or being a\r\n member of a specific group (e.g., military veterans or U.S.\r\n citizens) but (b) does not reveal the individual identity of the\r\n person that presents the credential. [M0404] (See: anonymity.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it mixes concepts\r\n in a potentially misleading way. For example, when the credential\r\n is an X.509 certificate, the term could be misunderstood to mean\r\n that the certificate was signed by a CA that has a persona\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 22 of 436\n\ncertificate. Instead, use \"attribute certificate\", \"organizational\r\n certificate\", or \"persona certificate\" depending on what is meant,\r\n and provide additional explanations as needed.\r\n $ anonymous login\r\n (I) An access control feature (actually, an access control\r\n vulnerability) in many Internet hosts that enables users to gain\r\n access to general-purpose or public services and resources of a\r\n host (such as allowing any user to transfer data using FTP)\r\n without having a pre-established, identity-specific account (i.e.,\r\n user name and password). (See: anonymity.)\r\n Tutorial: This feature exposes a system to more threats than when\r\n all the users are known, pre-registered entities that are\r\n individually accountable for their actions. A user logs in using a\r\n special, publicly known user name (e.g., \"anonymous\", \"guest\", or\r\n \"ftp\"). To use the public login name, the user is not required to\r\n know a secret password and may not be required to input anything\r\n at all except the name. In other cases, to complete the normal\r\n sequence of steps in a login protocol, the system may require the\r\n user to input a matching, publicly known password (such as\r\n \"anonymous\") or may ask the user for an e-mail address or some\r\n other arbitrary character string.\r\n $ ANSI\r\n (N) See: American National Standards Institute.\r\n $ anti-jam\r\n (N) \"Measures ensuring that transmitted information can be\r\n received despite deliberate jamming attempts.\" [C4009] (See:\r\n electronic security, frequency hopping, jam, spread spectrum.)\r\nShirey Informational [Page 19]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ apex trust anchor\r\n (N) The trust anchor that is superior to all other trust anchors\r\n in a particular system or context. (See: trust anchor, top CA.)\r\n $ API\r\n (I) See: application programming interface.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 23 of 436\n\n$ APOP\r\n (I) See: POP3 APOP.\r\n $ Application Layer\r\n See: Internet Protocol Suite, OSIRM.\r\n $ application program\r\n (I) A computer program that performs a specific function directly\r\n for a user (as opposed to a program that is part of a computer\r\n operating system and exists to perform functions in support of\r\n application programs).\r\n $ architecture\r\n (I) See: security architecture, system architecture.\r\n $ archive\r\n 1a. (I) /noun/ A collection of data that is stored for a\r\n relatively long period of time for historical and other purposes,\r\n such as to support audit service, availability service, or system\r\n integrity service. (Compare: backup, repository.)\r\n 1b. (I) /verb/ To store data in such a way as to create an\r\n archive. (Compare: back up.)\r\n Tutorial: A digital signature may need to be verified many years\r\n after the signing occurs. The CA -- the one that issued the\r\n certificate containing the public key needed to verify that\r\n signature -- may not stay in operation that long. So every CA\r\n needs to provide for long-term storage of the information needed\r\n to verify the signatures of those to whom it issues certificates.\r\n $ ARPANET\r\n (I) Advanced Research Projects Agency (ARPA) Network, a pioneer\r\n packet-switched network that (a) was designed, implemented,\r\n operated, and maintained by BBN from January 1969 until July 1975\r\n under contract to the U.S. Government; (b) led to the development\r\n of today's Internet; and (c) was decommissioned in June 1990.\r\n [B4799, Hafn]\r\n $ ASCII\r\n (N) See: American Standard Code for Information Interchange.\r\nShirey Informational [Page 20]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 24 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ ASN.1\r\n (N) See: Abstract Syntax Notation One.\r\n $ asset\r\n (I) A system resource that is (a) required to be protected by an\r\n information system's security policy, (b) intended to be protected\r\n by a countermeasure, or (c) required for a system's mission.\r\n $ association\r\n (I) A cooperative relationship between system entities, usually\r\n for the purpose of transferring information between them. (See:\r\n security association.)\r\n $ assurance See: security assurance.\r\n $ assurance level\r\n (N) A rank on a hierarchical scale that judges the confidence\r\n someone can have that a TOE adequately fulfills stated security\r\n requirements. (See: assurance, certificate policy, EAL, TCSEC.)\r\n Example: U.S. Government guidance [M0404] describes four assurance\r\n levels for identity authentication, where each level \"describes\r\n the [U.S. Federal Government] agency's degree of certainty that\r\n the user has presented [a credential] that refers to [the user's]\r\n identity.\" In that guidance, assurance is defined as (a) \"the\r\n degree of confidence in the vetting process used to establish the\r\n identity of the individual to whom the credential was issued\" and\r\n (b) \"the degree of confidence that the individual who uses the\r\n credential is the individual to whom the credential was issued.\"\r\n The four levels are described as follows:\r\n - Level 1: Little or no confidence in the asserted identity.\r\n - Level 2: Some confidence in the asserted identity.\r\n - Level 3: High confidence in the asserted identity.\r\n - Level 4: Very high confidence in the asserted identity.\r\n Standards for determining these levels are provided in a NIST\r\n publication [SP12]. However, as noted there, an assurance level is\r\n \"a degree of confidence, not a true measure of how secure the\r\n system actually is. This distinction is necessary because it is\r\n extremely difficult -- and in many cases, virtually impossible --\r\n to know exactly how secure a system is.\"\r\n $ asymmetric cryptography\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 25 of 436\n\n(I) A modern branch of cryptography (popularly known as \"public-\r\n key cryptography\") in which the algorithms use a pair of keys (a\r\n public key and a private key) and use a different component of the\r\n pair for each of two counterpart cryptographic operations (e.g.,\r\nShirey Informational [Page 21]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n encryption and decryption, or signature creation and signature\r\n verification). (See: key pair, symmetric cryptography.)\r\n Tutorial: Asymmetric algorithms have key management advantages\r\n over equivalently strong symmetric ones. First, one key of the\r\n pair need not be known by anyone but its owner; so it can more\r\n easily be kept secret. Second, although the other key is shared by\r\n all entities that use the algorithm, that key need not be kept\r\n secret from other, non-using entities; thus, the key-distribution\r\n part of key management can be done more easily.\r\n Asymmetric cryptography can be used to create algorithms for\r\n encryption, digital signature, and key agreement:\r\n - In an asymmetric encryption algorithm (e.g., \"RSA\"), when Alice\r\n wants to ensure confidentiality for data she sends to Bob, she\r\n encrypts the data with a public key provided by Bob. Only Bob\r\n has the matching private key that is needed to decrypt the\r\n data. (Compare: seal.)\r\n - In an asymmetric digital signature algorithm (e.g., \"DSA\"),\r\n when Alice wants to ensure data integrity or provide\r\n authentication for data she sends to Bob, she uses her private\r\n key to sign the data (i.e., create a digital signature based on\r\n the data). To verify the signature, Bob uses the matching\r\n public key that Alice has provided.\r\n - In an asymmetric key-agreement algorithm (e.g., \"Diffie-\r\n Hellman-Merkle\"), Alice and Bob each send their own public key\r\n to the other party. Then each uses their own private key and\r\n the other's public key to compute the new key value.\r\n $ asymmetric key\r\n (I) A cryptographic key that is used in an asymmetric\r\n cryptographic algorithm. (See: asymmetric cryptography, private\r\n key, public key.)\r\n $ ATIS\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 26 of 436\n\n(N) See: \"Alliance for Telecommunications Industry Solutions\"\r\n under \"ANSI\".\r\n $ attack\r\n 1. (I) An intentional act by which an entity attempts to evade\r\n security services and violate the security policy of a system.\r\n That is, an actual assault on system security that derives from an\r\n intelligent threat. (See: penetration, violation, vulnerability.)\r\n 2. (I) A method or technique used in an assault (e.g.,\r\n masquerade). (See: blind attack, distributed attack.)\r\nShirey Informational [Page 22]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Attacks can be characterized according to intent:\r\n - An \"active attack\" attempts to alter system resources or affect\r\n their operation.\r\n - A \"passive attack\" attempts to learn or make use of information\r\n from a system but does not affect system resources of that\r\n system. (See: wiretapping.)\r\n The object of a passive attack might be to obtain data that is\r\n needed for an off-line attack.\r\n - An \"off-line attack\" is one in which the attacker obtains data\r\n from the target system and then analyzes the data on a\r\n different system of the attacker's own choosing, possibly in\r\n preparation for a second stage of attack on the target.\r\n Attacks can be characterized according to point of initiation:\r\n - An \"inside attack\" is one that is initiated by an entity inside\r\n the security perimeter (an \"insider\"), i.e., an entity that is\r\n authorized to access system resources but uses them in a way\r\n not approved by the party that granted the authorization.\r\n - An \"outside attack\" is initiated from outside the security\r\n perimeter, by an unauthorized or illegitimate user of the\r\n system (an \"outsider\"). In the Internet, potential outside\r\n attackers range from amateur pranksters to organized criminals,\r\n international terrorists, and hostile governments.\r\n Attacks can be characterized according to method of delivery:\r\n - In a \"direct attack\", the attacker addresses attacking packets\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 27 of 436\n\nto the intended victim(s).\r\n - In an \"indirect attack\", the attacker addresses packets to a\r\n third party, and the packets either have the address(es) of the\r\n intended victim(s) as their source address(es) or indicate the\r\n intended victim(s) in some other way. The third party responds\r\n by sending one or more attacking packets to the intended\r\n victims. The attacker can use third parties as attack\r\n amplifiers by providing a broadcast address as the victim\r\n address (e.g., \"smurf attack\"). (See: reflector attack.\r\n Compare: reflection attack, replay attack.)\r\nShirey Informational [Page 23]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n The term \"attack\" relates to some other basic security terms as\r\n shown in the following diagram:\r\n + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+\r\n | An Attack: | |Counter- | | A System Resource: |\r\n | i.e., A Threat Action | | measure | | Target of the Attack |\r\n | +----------+ | | | | +-----------------+ |\r\n | | Attacker |\u003c==================||\u003c========= | |\r\n | | i.e., | Passive | | | | | Vulnerability | |\r\n | | A Threat |\u003c=================\u003e||\u003c========\u003e | |\r\n | | Agent | or Active | | | | +-------|||-------+ |\r\n | +----------+ Attack | | | | VVV |\r\n | | | | | Threat Consequences |\r\n + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+\r\n $ attack potential\r\n (I) The perceived likelihood of success should an attack be\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 28 of 436\n\nlaunched, expressed in terms of the attacker's ability (i.e.,\r\n expertise and resources) and motivation. (Compare: threat, risk.)\r\n $ attack sensing, warning, and response\r\n (I) A set of security services that cooperate with audit service\r\n to detect and react to indications of threat actions, including\r\n both inside and outside attacks. (See: indicator.)\r\n $ attack tree\r\n (I) A branching, hierarchical data structure that represents a set\r\n of potential approaches to achieving an event in which system\r\n security is penetrated or compromised in a specified way. [Moor]\r\n Tutorial: Attack trees are special cases of fault trees. The\r\n security incident that is the goal of the attack is represented as\r\n the root node of the tree, and the ways that an attacker could\r\n reach that goal are iteratively and incrementally represented as\r\n branches and subnodes of the tree. Each subnode defines a subgoal,\r\n and each subgoal may have its own set of further subgoals, etc.\r\n The final nodes on the paths outward from the root, i.e., the leaf\r\n nodes, represent different ways to initiate an attack. Each node\r\n other than a leaf is either an AND-node or an OR-node. To achieve\r\n the goal represented by an AND-node, the subgoals represented by\r\n all of that node's subnodes must be achieved; and for an OR-node,\r\n at least one of the subgoals must be achieved. Branches can be\r\n labeled with values representing difficulty, cost, or other attack\r\n attributes, so that alternative attacks can be compared.\r\nShirey Informational [Page 24]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ attribute\r\n (N) Information of a particular type concerning an identifiable\r\n system entity or object. An \"attribute type\" is the component of\r\n an attribute that indicates the class of information given by the\r\n attribute; and an \"attribute value\" is a particular instance of\r\n the class of information indicated by an attribute type. (See:\r\n attribute certificate.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 29 of 436\n\n$ attribute authority (AA)\r\n 1. (N) A CA that issues attribute certificates.\r\n 2. (O) \"An authority [that] assigns privileges by issuing\r\n attribute certificates.\" [X509]\r\n Deprecated Usage: The abbreviation \"AA\" SHOULD NOT be used in an\r\n IDOC unless it is first defined in the IDOC.\r\n $ attribute certificate\r\n 1. (I) A digital certificate that binds a set of descriptive data\r\n items, other than a public key, either directly to a subject name\r\n or to the identifier of another certificate that is a public-key\r\n certificate. (See: capability token.)\r\n 2. (O) \"A data structure, digitally signed by an [a]ttribute\r\n [a]uthority, that binds some attribute values with identification\r\n information about its holder.\" [X509]\r\n Tutorial: A public-key certificate binds a subject name to a\r\n public key value, along with information needed to perform certain\r\n cryptographic functions using that key. Other attributes of a\r\n subject, such as a security clearance, may be certified in a\r\n separate kind of digital certificate, called an attribute\r\n certificate. A subject may have multiple attribute certificates\r\n associated with its name or with each of its public-key\r\n certificates.\r\n An attribute certificate might be issued to a subject in the\r\n following situations:\r\n - Different lifetimes: When the lifetime of an attribute binding\r\n is shorter than that of the related public-key certificate, or\r\n when it is desirable not to need to revoke a subject's public\r\n key just to revoke an attribute.\r\n - Different authorities: When the authority responsible for the\r\n attributes is different than the one that issues the public-key\r\n certificate for the subject. (There is no requirement that an\r\n attribute certificate be issued by the same CA that issued the\r\n associated public-key certificate.)\r\nShirey Informational [Page 25]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 30 of 436\n\n$ audit\r\n See: security audit.\r\n $ audit log\r\n (I) Synonym for \"security audit trail\".\r\n $ audit service\r\n (I) A security service that records information needed to\r\n establish accountability for system events and for the actions of\r\n system entities that cause them. (See: security audit.)\r\n $ audit trail\r\n (I) See: security audit trail.\r\n $ AUTH\r\n (I) See: POP3 AUTH.\r\n $ authenticate\r\n (I) Verify (i.e., establish the truth of) an attribute value\r\n claimed by or for a system entity or system resource. (See:\r\n authentication, validate vs. verify, \"relationship between data\r\n integrity service and authentication services\" under \"data\r\n integrity service\".)\r\n Deprecated Usage: In general English usage, this term is used with\r\n the meaning \"to prove genuine\" (e.g., an art expert authenticates\r\n a Michelangelo painting); but IDOCs should restrict usage as\r\n follows:\r\n - IDOCs SHOULD NOT use this term to refer to proving or checking\r\n that data has not been changed, destroyed, or lost in an\r\n unauthorized or accidental manner. Instead, use \"verify\".\r\n - IDOCs SHOULD NOT use this term to refer to proving the truth or\r\n accuracy of a fact or value such as a digital signature.\r\n Instead, use \"verify\".\r\n - IDOCs SHOULD NOT use this term to refer to establishing the\r\n soundness or correctness of a construct, such as a digital\r\n certificate. Instead, use \"validate\".\r\n $ authentication\r\n (I) The process of verifying a claim that a system entity or\r\n system resource has a certain attribute value. (See: attribute,\r\n authenticate, authentication exchange, authentication information,\r\n credential, data origin authentication, peer entity\r\n authentication, \"relationship between data integrity service and\r\n authentication services\" under \"data integrity service\", simple\r\n authentication, strong authentication, verification, X.509.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 31 of 436\n\nShirey Informational [Page 26]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Security services frequently depend on authentication of\r\n the identity of users, but authentication may involve any type of\r\n attribute that is recognized by a system. A claim may be made by a\r\n subject about itself (e.g., at login, a user typically asserts its\r\n identity) or a claim may be made on behalf of a subject or object\r\n by some other system entity (e.g., a user may claim that a data\r\n object originates from a specific source, or that a data object is\r\n classified at a specific security level).\r\n An authentication process consists of two basic steps:\r\n - Identification step: Presenting the claimed attribute value\r\n (e.g., a user identifier) to the authentication subsystem.\r\n - Verification step: Presenting or generating authentication\r\n information (e.g., a value signed with a private key) that acts\r\n as evidence to prove the binding between the attribute and that\r\n for which it is claimed. (See: verification.)\r\n $ authentication code\r\n (D) Synonym for a checksum based on cryptography. (Compare: Data\r\n Authentication Code, Message Authentication Code.)\r\n Deprecated Term: IDOCs SHOULD NOT use this uncapitalized term as a\r\n synonym for any kind of checksum, regardless of whether or not the\r\n checksum is cryptographic. Instead, use \"checksum\", \"Data\r\n Authentication Code\", \"error detection code\", \"hash\", \"keyed\r\n hash\", \"Message Authentication Code\", \"protected checksum\", or\r\n some other recommended term, depending on what is meant.\r\n The term mixes concepts in a potentially misleading way. The word\r\n \"authentication\" is misleading because the checksum may be used to\r\n perform a data integrity function rather than a data origin\r\n authentication function.\r\n $ authentication exchange\r\n 1. (I) A mechanism to verify the identity of an entity by means of\r\n information exchange.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 32 of 436\n\n2. (O) \"A mechanism intended to ensure the identity of an entity\r\n by means of information exchange.\" [I7498-2]\r\n $ Authentication Header (AH)\r\n (I) An Internet protocol [R2402, R4302] designed to provide\r\n connectionless data integrity service and connectionless data\r\n origin authentication service for IP datagrams, and (optionally)\r\n to provide partial sequence integrity and protection against\r\n replay attacks. (See: IPsec. Compare: ESP.)\r\nShirey Informational [Page 27]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Replay protection may be selected by the receiver when a\r\n security association is established. AH authenticates the upper-\r\n layer PDU that is carried as an IP SDU, and also authenticates as\r\n much of the IP PCI (i.e., the IP header) as possible. However,\r\n some IP header fields may change in transit, and the value of\r\n these fields, when the packet arrives at the receiver, may not be\r\n predictable by the sender. Thus, the values of such fields cannot\r\n be protected end-to-end by AH; protection of the IP header by AH\r\n is only partial when such fields are present.\r\n AH may be used alone, or in combination with the ESP, or in a\r\n nested fashion with tunneling. Security services can be provided\r\n between a pair of communicating hosts, between a pair of\r\n communicating security gateways, or between a host and a gateway.\r\n ESP can provide nearly the same security services as AH, and ESP\r\n can also provide data confidentiality service. The main difference\r\n between authentication services provided by ESP and AH is the\r\n extent of the coverage; ESP does not protect IP header fields\r\n unless they are encapsulated by AH.\r\n $ authentication information\r\n (I) Information used to verify an identity claimed by or for an\r\n entity. (See: authentication, credential, user. Compare:\r\n identification information.)\r\n Tutorial: Authentication information may exist as, or be derived\r\n from, one of the following: (a) Something the entity knows (see:\r\n password); (b) something the entity possesses (see: token); (c)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 33 of 436\n\nsomething the entity is (see: biometric authentication).\r\n $ authentication service\r\n (I) A security service that verifies an identity claimed by or for\r\n an entity. (See: authentication.)\r\n Tutorial: In a network, there are two general forms of\r\n authentication service: data origin authentication service and\r\n peer entity authentication service.\r\n $ authenticity\r\n (I) The property of being genuine and able to be verified and be\r\n trusted. (See: authenticate, authentication, validate vs. verify.)\r\n $ authority\r\n (D) /PKI/ \"An entity [that is] responsible for the issuance of\r\n certificates.\" [X509]\r\nShirey Informational [Page 28]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n attribute authority, certification authority, registration\r\n authority, or similar terms; the shortened form may cause\r\n confusion. Instead, use the full term at the first instance of\r\n usage and then, if it is necessary to shorten text, use AA, CA,\r\n RA, and other abbreviations defined in this Glossary.\r\n $ authority certificate\r\n (D) \"A certificate issued to an authority (e.g. either to a\r\n certification authority or to an attribute authority).\" [X509]\r\n (See: authority.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is\r\n ambiguous. Instead, use the full term \"certification authority\r\n certificate\", \"attribute authority certificate\", \"registration\r\n authority certificate\", etc. at the first instance of usage and\r\n then, if it is necessary to shorten text, use AA, CA, RA, and\r\n other abbreviations defined in this Glossary.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 34 of 436\n\n$ Authority Information Access extension\r\n (I) The private extension defined by PKIX for X.509 certificates\r\n to indicate \"how to access CA information and services for the\r\n issuer of the certificate in which the extension appears.\r\n Information and services may include on-line validation services\r\n and CA policy data.\" [R3280] (See: private extension.)\r\n $ authorization\r\n 1a. (I) An approval that is granted to a system entity to access a\r\n system resource. (Compare: permission, privilege.)\r\n Usage: Some synonyms are \"permission\" and \"privilege\". Specific\r\n terms are preferred in certain contexts:\r\n - /PKI/ \"Authorization\" SHOULD be used, to align with\r\n \"certification authority\" in the standard [X509].\r\n - /role-based access control/ \"Permission\" SHOULD be used, to\r\n align with the standard [ANSI].\r\n - /computer operating systems/ \"Privilege\" SHOULD be used, to\r\n align with the literature. (See: privileged process, privileged\r\n user.)\r\n Tutorial: The semantics and granularity of authorizations depend\r\n on the application and implementation (see: \"first law\" under\r\n \"Courtney's laws\"). An authorization may specify a particular\r\n access mode -- such as read, write, or execute -- for one or more\r\n system resources.\r\n 1b. (I) A process for granting approval to a system entity to\r\n access a system resource.\r\nShirey Informational [Page 29]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) /SET/ \"The process by which a properly appointed person or\r\n persons grants permission to perform some action on behalf of an\r\n organization. This process assesses transaction risk, confirms\r\n that a given transaction does not raise the account holder's debt\r\n above the account's credit limit, and reserves the specified\r\n amount of credit. (When a merchant obtains authorization, payment\r\n for the authorized amount is guaranteed -- provided, of course,\r\n that the merchant followed the rules associated with the\r\n authorization process.)\" [SET2]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 35 of 436\n\n$ authorization credential\r\n (I) See: /access control/ under \"credential\".\r\n $ authorize\r\n (I) Grant an authorization to a system entity.\r\n $ authorized user\r\n (I) /access control/ A system entity that accesses a system\r\n resource for which the entity has received an authorization.\r\n (Compare: insider, outsider, unauthorized user.)\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the term is used in many ways and could\r\n easily be misunderstood.\r\n $ automated information system\r\n See: information system.\r\n $ availability\r\n 1. (I) The property of a system or a system resource being\r\n accessible, or usable or operational upon demand, by an authorized\r\n system entity, according to performance specifications for the\r\n system; i.e., a system is available if it provides services\r\n according to the system design whenever users request them. (See:\r\n critical, denial of service. Compare: precedence, reliability,\r\n survivability.)\r\n 2. (O) \"The property of being accessible and usable upon demand by\r\n an authorized entity.\" [I7498-2]\r\n 3. (D) \"Timely, reliable access to data and information services\r\n for authorized users.\" [C4009]\r\n Deprecated Definition: IDOCs SHOULD NOT use the term with\r\n definition 3; the definition mixes \"availability\" with\r\n \"reliability\", which is a different property. (See: reliability.)\r\nShirey Informational [Page 30]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Availability requirements can be specified by\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 36 of 436\n\nquantitative metrics, but sometimes are stated qualitatively, such\r\n as in the following:\r\n - \"Flexible tolerance for delay\" may mean that brief system\r\n outages do not endanger mission accomplishment, but extended\r\n outages may endanger the mission.\r\n - \"Minimum tolerance for delay\" may mean that mission\r\n accomplishment requires the system to provide requested\r\n services in a short time.\r\n $ availability service\r\n (I) A security service that protects a system to ensure its\r\n availability.\r\n Tutorial: This service addresses the security concerns raised by\r\n denial-of-service attacks. It depends on proper management and\r\n control of system resources, and thus depends on access control\r\n service and other security services.\r\n $ avoidance\r\n (I) See: secondary definition under \"security\".\r\n $ B1, B2, or B3 computer system\r\n (O) /TCSEC/ See: Tutorial under \"Trusted Computer System\r\n Evaluation Criteria\".\r\n $ back door\r\n 1. (I) /COMPUSEC/ A computer system feature -- which may be (a) an\r\n unintentional flaw, (b) a mechanism deliberately installed by the\r\n system's creator, or (c) a mechanism surreptitiously installed by\r\n an intruder -- that provides access to a system resource by other\r\n than the usual procedure and usually is hidden or otherwise not\r\n well-known. (See: maintenance hook. Compare: Trojan Horse.)\r\n Example: A way to access a computer other than through a normal\r\n login. Such an access path is not necessarily designed with\r\n malicious intent; operating systems sometimes are shipped by the\r\n manufacturer with hidden accounts intended for use by field\r\n service technicians or the vendor's maintenance programmers.\r\n 2. (I) /cryptography/ A feature of a cryptographic system that\r\n makes it easily possible to break or circumvent the protection\r\n that the system is designed to provide.\r\n Example: A feature that makes it possible to decrypt cipher text\r\n much more quickly than by brute-force cryptanalysis, without\r\n having prior knowledge of the decryption key.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 37 of 436\n\nShirey Informational [Page 31]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ back up\r\n (I) /verb/ Create a reserve copy of data or, more generally,\r\n provide alternate means to perform system functions despite loss\r\n of system resources. (See: contingency plan. Compare: archive.)\r\n $ backup\r\n (I) /noun or adjective/ Refers to alternate means of performing\r\n system functions despite loss of system resources. (See:\r\n contingency plan).\r\n Example: A reserve copy of data, preferably one that is stored\r\n separately from the original, for use if the original becomes lost\r\n or damaged. (Compare: archive.)\r\n $ bagbiter\r\n (D) /slang/ \"An entity, such as a program or a computer, that\r\n fails to work or that works in a remarkably clumsy manner. A\r\n person who has caused some trouble, inadvertently or otherwise,\r\n typically by failing to program the computer properly.\" [NCSSG]\r\n (See: flaw.)\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for these concepts. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ baggage\r\n (O) /SET/ An \"opaque encrypted tuple, which is included in a SET\r\n message but appended as external data to the PKCS encapsulated\r\n data. This avoids superencryption of the previously encrypted\r\n tuple, but guarantees linkage with the PKCS portion of the\r\n message.\" [SET2]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term to describe a\r\n data element, except in the form \"SET(trademark) baggage\" with the\r\n meaning given above.\r\n $ baked-in security\r\n (D) The inclusion of security mechanisms in an information system\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 38 of 436\n\nbeginning at an early point in the system's lifecycle, i.e.,\r\n during the design phase, or at least early in the implementation\r\n phase. (Compare: add-on security.)\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term (unless they also\r\n provide a definition like this one). (See: Deprecated Usage under\r\n \"Green Book\".)\r\nShirey Informational [Page 32]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ bandwidth\r\n (I) The total width of the frequency band that is available to or\r\n used by a communication channel; usually expressed in Hertz (Hz).\r\n (RFC 3753) (Compare: channel capacity.)\r\n $ bank identification number (BIN)\r\n 1. (O) The digits of a credit card number that identify the\r\n issuing bank. (See: primary account number.)\r\n 2. (O) /SET/ The first six digits of a primary account number.\r\n $ Basic Encoding Rules (BER)\r\n (I) A standard for representing ASN.1 data types as strings of\r\n octets. [X690] (See: Distinguished Encoding Rules.)\r\n Deprecated Usage: Sometimes incorrectly treated as part of ASN.1.\r\n However, ASN.1 properly refers only to a syntax description\r\n language, and not to the encoding rules for the language.\r\n $ Basic Security Option\r\n (I) See: secondary definition under \"IPSO\".\r\n $ bastion host\r\n (I) A strongly protected computer that is in a network protected\r\n by a firewall (or is part of a firewall) and is the only host (or\r\n one of only a few) in the network that can be directly accessed\r\n from networks on the other side of the firewall. (See: firewall.)\r\n Tutorial: Filtering routers in a firewall typically restrict\r\n traffic from the outside network to reaching just one host, the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 39 of 436\n\nbastion host, which usually is part of the firewall. Since only\r\n this one host can be directly attacked, only this one host needs\r\n to be very strongly protected, so security can be maintained more\r\n easily and less expensively. However, to allow legitimate internal\r\n and external users to access application resources through the\r\n firewall, higher-layer protocols and services need to be relayed\r\n and forwarded by the bastion host. Some services (e.g., DNS and\r\n SMTP) have forwarding built in; other services (e.g., TELNET and\r\n FTP) require a proxy server on the bastion host.\r\n $ BBN Technologies Corp. (BBN)\r\n (O) The research-and-development company (originally called Bolt\r\n Baranek and Newman, Inc.) that built the ARPANET.\r\n $ BCA\r\n (O) See: brand certification authority.\r\nShirey Informational [Page 33]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ BCR\r\n (O) See: BLACK/Crypto/RED.\r\n $ BCI\r\n (O) See: brand CRL identifier.\r\n $ Bell-LaPadula model\r\n (N) A formal, mathematical, state-transition model of\r\n confidentiality policy for multilevel-secure computer systems\r\n [Bell]. (Compare: Biba model, Brewer-Nash model.)\r\n Tutorial: The model, devised by David Bell and Leonard LaPadula at\r\n The MITRE Corporation in 1973, characterizes computer system\r\n elements as subjects and objects. To determine whether or not a\r\n subject is authorized for a particular access mode on an object,\r\n the clearance of the subject is compared to the classification of\r\n the object. The model defines the notion of a \"secure state\", in\r\n which the only permitted access modes of subjects to objects are\r\n in accordance with a specified security policy. It is proven that\r\n each state transition preserves security by moving from secure\r\n state to secure state, thereby proving that the system is secure.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 40 of 436\n\nIn this model, a multilevel-secure system satisfies several rules,\r\n including the \"confinement property\" (a.k.a. the \"*-property\"),\r\n the \"simple security property\", and the \"tranquility property\".\r\n $ benign\r\n 1. (N) /COMSEC/ \"Condition of cryptographic data [such] that [the\r\n data] cannot be compromised by human access [to the data].\"\r\n [C4009]\r\n 2. (O) /COMPUSEC/ See: secondary definition under \"trust\".\r\n $ benign fill\r\n (N) Process by which keying material is generated, distributed,\r\n and placed into an ECU without exposure to any human or other\r\n system entity, except the cryptographic module that consumes and\r\n uses the material. (See: benign.)\r\n $ BER\r\n (I) See: Basic Encoding Rules.\r\n $ beyond A1\r\n 1. (O) /formal/ A level of security assurance that is beyond the\r\n highest level (level A1) of criteria specified by the TCSEC. (See:\r\n Tutorial under \"Trusted Computer System Evaluation Criteria\".)\r\nShirey Informational [Page 34]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) /informal/ A level of trust so high that it is beyond\r\n state-of-the-art technology; i.e., it cannot be provided or\r\n verified by currently available assurance methods, and especially\r\n not by currently available formal methods.\r\n $ Biba integrity\r\n (N) Synonym for \"source integrity\".\r\n $ Biba model\r\n (N) A formal, mathematical, state-transition model of integrity\r\n policy for multilevel-secure computer systems [Biba]. (See: source\r\n integrity. Compare: Bell-LaPadula model.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 41 of 436\n\nTutorial: This model for integrity control is analogous to the\r\n Bell-LaPadula model for confidentiality control. Each subject and\r\n object is assigned an integrity level and, to determine whether or\r\n not a subject is authorized for a particular access mode on an\r\n object, the integrity level of the subject is compared to that of\r\n the object. The model prohibits the changing of information in an\r\n object by a subject with a lesser or incomparable level. The rules\r\n of the Biba model are duals of the corresponding rules in the\r\n Bell-LaPadula model.\r\n $ billet\r\n (N) \"A personnel position or assignment that may be filled by one\r\n person.\" [JCP1] (Compare: principal, role, user.)\r\n Tutorial: In an organization, a \"billet\" is a populational\r\n position, of which there is exactly one instance; but a \"role\" is\r\n functional position, of which there can be multiple instances.\r\n System entities are in one-to-one relationships with their\r\n billets, but may be in many-to-one and one-to-many relationships\r\n with their roles.\r\n $ BIN\r\n (O) See: bank identification number.\r\n $ bind\r\n (I) To inseparably associate by applying some security mechanism.\r\n Example: A CA creates a public-key certificate by using a digital\r\n signature to bind together (a) a subject name, (b) a public key,\r\n and usually (c) some additional data items (e.g., \"X.509 public-\r\n key certificate\").\r\n $ biometric authentication\r\n (I) A method of generating authentication information for a person\r\n by digitizing measurements of a physical or behavioral\r\nShirey Informational [Page 35]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n characteristic, such as a fingerprint, hand shape, retina pattern,\r\n voiceprint, handwriting style, or face.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 42 of 436\n\n$ birthday attack\r\n (I) A class of attacks against cryptographic functions, including\r\n both encryption functions and hash functions. The attacks take\r\n advantage of a statistical property: Given a cryptographic\r\n function having an N-bit output, the probability is greater than\r\n 1/2 that for 2**(N/2) randomly chosen inputs, the function will\r\n produce at least two outputs that are identical. (See: Tutorial\r\n under \"hash function\".)\r\n Derivation: From the somewhat surprising fact (often called the\r\n \"birthday paradox\") that although there are 365 days in a year,\r\n the probability is greater than 1/2 that two of more people share\r\n the same birthday in any randomly chosen group of 23 people.\r\n Birthday attacks enable an adversary to find two inputs for which\r\n a cryptographic function produces the same cipher text (or find\r\n two inputs for which a hash functions produces the same hash\r\n result) much faster than a brute-force attack can; and a clever\r\n adversary can use such a capability to create considerable\r\n mischief. However, no birthday attack can enable an adversary to\r\n decrypt a given cipher text (or find a hash input that results in\r\n a given hash result) any faster than a brute-force attack can.\r\n $ bit\r\n (I) A contraction of the term \"binary digit\"; the smallest unit of\r\n information storage, which has two possible states or values. The\r\n values usually are represented by the symbols \"0\" (zero) and \"1\"\r\n (one). (See: block, byte, nibble, word.)\r\n $ bit string\r\n (I) A sequence of bits, each of which is either \"0\" or \"1\".\r\n $ BLACK\r\n 1. (N) Designation for data that consists only of cipher text, and\r\n for information system equipment items or facilities that handle\r\n only cipher text. Example: \"BLACK key\". (See: BCR, color change,\r\n RED/BLACK separation. Compare: RED.)\r\n 2. (O) /U.S. Government/ \"Designation applied to information\r\n systems, and to associated areas, circuits, components, and\r\n equipment, in which national security information is encrypted or\r\n is not processed.\" [C4009]\r\n 3. (D) Any data that can be disclosed without harm.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 43 of 436\n\nShirey Informational [Page 36]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Definition: IDOCs SHOULD NOT use the term with\r\n definition 3 because the definition is ambiguous with regard to\r\n whether or not the data is protected.\r\n $ BLACK/Crypto/RED (BCR)\r\n (N) An experimental, end-to-end, network packet encryption system\r\n developed in a working prototype form by BBN and the Collins Radio\r\n division of Rockwell Corporation in the 1975-1980 time frame for\r\n the U.S. DoD. BCR was the first network security system to support\r\n TCP/IP traffic, and it incorporated the first DES chips that were\r\n validated by the U.S. National Bureau of Standards (now called\r\n NIST). BCR also was the first to use a KDC and an ACC to manage\r\n connections.\r\n $ BLACK key\r\n (N) A key that is protected with a key-encrypting key and that\r\n must be decrypted before use. (See: BLACK. Compare: RED key.)\r\n $ BLACKER\r\n (O) An end-to-end encryption system for computer data networks\r\n that was developed by the U.S. DoD in the 1980s to provide host-\r\n to-host data confidentiality service for datagrams at OSIRM Layer\r\n 3. [Weis] (Compare: CANEWARE, IPsec.)\r\n Tutorial: Each user host connects to its own bump-in-the-wire\r\n encryption device called a BLACKER Front End (BFE, TSEC/KI-111),\r\n through which the host connects to the subnetwork. The system also\r\n includes two types of centralized devices: one or more KDCs\r\n connect to the subnetwork and communicate with assigned sets of\r\n BFEs, and one or more ACCs connect to the subnetwork and\r\n communicate with assigned KDCs. BLACKER uses only symmetric\r\n encryption. A KDC distributes session keys to BFE pairs as\r\n authorized by an ACC. Each ACC maintains a database for a set of\r\n BFEs, and the database determines which pairs from that set (i.e.,\r\n which pairs of user hosts behind the BFEs) are authorized to\r\n communicate and at what security levels.\r\n The BLACKER system is MLS in three ways: (a) The BFEs form a\r\n security perimeter around a subnetwork, separating user hosts from\r\n the subnetwork, so that the subnetwork can operate at a different\r\n security level (possibly a lower, less expensive level) than the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 44 of 436\n\nhosts. (b) The BLACKER components are trusted to separate\r\n datagrams of different security levels, so that each datagram of a\r\n given security level can be received only by a host that is\r\n authorized for that security level; and thus BLACKER can separate\r\n host communities that operate at different security levels. (c)\r\n The host side of a BFE is itself MLS and can recognize a security\r\n label on each packet, so that an MLS user host can be authorized\r\nShirey Informational [Page 37]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n to successively transmit datagrams that are labeled with different\r\n security levels.\r\n $ blind attack\r\n (I) A type of network-based attack method that does not require\r\n the attacking entity to receive data traffic from the attacked\r\n entity; i.e., the attacker does not need to \"see\" data packets\r\n sent by the victim. Example: SYN flood.\r\n Tutorial: If an attack method is blind, the attacker's packets can\r\n carry (a) a false IP source address (making it difficult for the\r\n victim to find the attacker) and (b) a different address on every\r\n packet (making it difficult for the victim to block the attack).\r\n If the attacker needs to receive traffic from the victim, the\r\n attacker must either (c) reveal its own IP address to the victim\r\n (which enables the victim to find the attacker or block the attack\r\n by filtering) or (d) provide a false address and also subvert\r\n network routing mechanisms to divert the returning packets to the\r\n attacker (which makes the attack more complex, more difficult, or\r\n more expensive). [R3552]\r\n $ block\r\n (I) A bit string or bit vector of finite length. (See: bit, block\r\n cipher. Compare: byte, word.)\r\n Usage: An \"N-bit block\" contains N bits, which usually are\r\n numbered from left to right as 1, 2, 3, ..., N.\r\n $ block cipher\r\n (I) An encryption algorithm that breaks plain text into fixed-size\r\n segments and uses the same key to transform each plaintext segment\r\n into a fixed-size segment of cipher text. Examples: AES, Blowfish,\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 45 of 436\n\nDEA, IDEA, RC2, and SKIPJACK. (See: block, mode. Compare: stream\r\n cipher.)\r\n Tutorial: A block cipher can be adapted to have a different\r\n external interface, such as that of a stream cipher, by using a\r\n mode of cryptographic operation to package the basic algorithm.\r\n (See: CBC, CCM, CFB, CMAC, CTR, DEA, ECB, OFB.)\r\n $ Blowfish\r\n (N) A symmetric block cipher with variable-length key (32 to 448\r\n bits) designed in 1993 by Bruce Schneier as an unpatented,\r\n license-free, royalty-free replacement for DES or IDEA. [Schn]\r\n (See: Twofish.)\r\nShirey Informational [Page 38]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ brain-damaged\r\n (D) /slang/ \"Obviously wrong: extremely poorly designed. Calling\r\n something brain-damaged is very extreme. The word implies that the\r\n thing is completely unusable, and that its failure to work is due\r\n to poor design, not accident.\" [NCSSG] (See: flaw.)\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ brand\r\n 1. (I) A distinctive mark or name that identifies a product or\r\n business entity.\r\n 2. (O) /SET/ The name of a payment card. (See: BCA.)\r\n Tutorial: Financial institutions and other companies have founded\r\n payment card brands, protect and advertise the brands, establish\r\n and enforce rules for use and acceptance of their payment cards,\r\n and provide networks to interconnect the financial institutions.\r\n These brands combine the roles of issuer and acquirer in\r\n interactions with cardholders and merchants. [SET1]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 46 of 436\n\n$ brand certification authority (BCA)\r\n (O) /SET/ A CA owned by a payment card brand, such as MasterCard,\r\n Visa, or American Express. [SET2] (See: certification hierarchy,\r\n SET.)\r\n $ brand CRL identifier (BCI)\r\n (O) /SET/ A digitally signed list, issued by a BCA, of the names\r\n of CAs for which CRLs need to be processed when verifying\r\n signatures in SET messages. [SET2]\r\n $ break\r\n (I) /cryptography/ To successfully perform cryptanalysis and thus\r\n succeed in decrypting data or performing some other cryptographic\r\n function, without initially having knowledge of the key that the\r\n function requires. (See: penetrate, strength, work factor.)\r\n Usage: This term applies to encrypted data or, more generally, to\r\n a cryptographic algorithm or cryptographic system. Also, while the\r\n most common use is to refer to completely breaking an algorithm,\r\n the term is also used when a method is found that substantially\r\n reduces the work factor.\r\nShirey Informational [Page 39]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Brewer-Nash model\r\n (N) A security model [BN89] to enforce the Chinese wall policy.\r\n (Compare: Bell-LaPadula model, Clark-Wilson model.)\r\n Tutorial: All proprietary information in the set of commercial\r\n firms F(1), F(2), ..., F(N) is categorized into mutually exclusive\r\n conflict-of-interest classes I(1), I(2), ..., I(M) that apply\r\n across all firms. Each firm belongs to exactly one class. The\r\n Brewer-Nash model has the following mandatory rules:\r\n - Brewer-Nash Read Rule: Subject S can read information object O\r\n from firm F(i) only if either (a) O is from the same firm as\r\n some object previously read by S *or* (b) O belongs to a class\r\n I(i) from which S has not previously read any object. (See:\r\n object, subject.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 47 of 436\n\n- Brewer-Nash Write Rule: Subject S can write information object\r\n O to firm F(i) only if (a) S can read O by the Brewer-Nash Read\r\n Rule *and* (b) no object can be read by S from a different firm\r\n F(j), no matter whether F(j) belongs to the same class as F(i)\r\n or to a different class.\r\n $ bridge\r\n (I) A gateway for traffic flowing at OSIRM Layer 2 between two\r\n networks (usually two LANs). (Compare: bridge CA, router.)\r\n $ bridge CA\r\n (I) A PKI consisting of only a CA that cross-certifies with CAs of\r\n some other PKIs. (See: cross-certification. Compare: bridge.)\r\n Tutorial: A bridge CA functions as a hub that enables a\r\n certificate user in any of the PKIs that attach to the bridge, to\r\n validate certificates issued in the other attached PKIs.\r\n For example, a bridge CA (BCA) CA1\r\n could cross-certify with four ^\r\n PKIs that have the roots CA1, |\r\n CA2, CA3, and CA4. The cross- v\r\n certificates that the roots CA2 \u003c-\u003e BCA \u003c-\u003e CA3\r\n exchange with the BCA enable an ^\r\n end entity EE1 certified under |\r\n under CA1 in PK1 to construct v\r\n a certification path needed to CA4\r\n validate the certificate of\r\n end entity EE2 under CA2, CA1 -\u003e BCA -\u003e CA2 -\u003e EE2\r\n or vice versa. CA2 -\u003e BCA -\u003e CA1 -\u003e EE1\r\nShirey Informational [Page 40]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ British Standard 7799\r\n (N) Part 1 of the standard is a code of practice for how to secure\r\n an information system. Part 2 specifies the management framework,\r\n objectives, and control requirements for information security\r\n management systems. [BS7799] (See: ISO 17799.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 48 of 436\n\n$ browser\r\n (I) A client computer program that can retrieve and display\r\n information from servers on the World Wide Web. Examples: Netscape\r\n Navigator and Microsoft Internet Explorer.\r\n $ brute force\r\n (I) A cryptanalysis technique or other kind of attack method\r\n involving an exhaustive procedure that tries a large number of\r\n possible solutions to the problem. (See: impossible, strength,\r\n work factor.)\r\n Tutorial: In some cases, brute force involves trying all of the\r\n possibilities. For example, for cipher text where the analyst\r\n already knows the decryption algorithm, a brute-force technique\r\n for finding matching plain text is to decrypt the message with\r\n every possible key. In other cases, brute force involves trying a\r\n large number of possibilities but substantially fewer than all of\r\n them. For example, given a hash function that produces an N-bit\r\n hash result, the probability is greater than 1/2 that the analyst\r\n will find two inputs that have the same hash result after trying\r\n only 2**(N/2) randomly chosen inputs. (See: birthday attack.)\r\n $ BS7799\r\n (N) See: British Standard 7799.\r\n $ buffer overflow\r\n (I) Any attack technique that exploits a vulnerability resulting\r\n from computer software or hardware that does not check for\r\n exceeding the bounds of a storage area when data is written into a\r\n sequence of storage locations beginning in that area.\r\n Tutorial: By causing a normal system operation to write data\r\n beyond the bounds of a storage area, the attacker seeks to either\r\n disrupt system operation or cause the system to execute malicious\r\n software inserted by the attacker.\r\n $ buffer zone\r\n (I) A neutral internetwork segment used to connect other segments\r\n that each operate under a different security policy.\r\nShirey Informational [Page 41]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 49 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: To connect a private network to the Internet or some\r\n other relatively public network, one could construct a small,\r\n separate, isolated LAN and connect it to both the private network\r\n and the public network; one or both of the connections would\r\n implement a firewall to limit the traffic that could pass through\r\n the buffer zone.\r\n $ bulk encryption\r\n 1. (I) Encryption of multiple channels by aggregating them into a\r\n single transfer path and then encrypting that path. (See:\r\n channel.)\r\n 2. (O) \"Simultaneous encryption of all channels of a multichannel\r\n telecommunications link.\" [C4009] (Compare: bulk keying material.)\r\n Usage: The use of \"simultaneous\" in definition 2 could be\r\n interpreted to mean that multiple channels are encrypted\r\n separately but at the same time. However, the common meaning of\r\n the term is that multiple data flows are combined into a single\r\n stream and then that stream is encrypted as a whole.\r\n $ bulk key\r\n (D) In a few published descriptions of hybrid encryption for SSH,\r\n Windows 2000, and other applications, this term refers to a\r\n symmetric key that (a) is used to encrypt a relatively large\r\n amount of data and (b) is itself encrypted with a public key.\r\n (Compare: bulk keying material, session key.)\r\n Example: To send a large file to Bob, Alice (a) generates a\r\n symmetric key and uses it to encrypt the file (i.e., encrypt the\r\n bulk of the information that is to be sent) and then (b) encrypts\r\n that symmetric key (the \"bulk key\") with Bob's public key.\r\n Deprecated Term: IDOCs SHOULD NOT use this term or definition; the\r\n term is not well-established and could be confused with the\r\n established term \"bulk keying material\". Instead, use \"symmetric\r\n key\" and carefully explain how the key is applied.\r\n $ bulk keying material\r\n (N) Refers to handling keying material in large quantities, e.g.,\r\n as a dataset that contains many items of keying material. (See:\r\n type 0. Compare: bulk key, bulk encryption.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 50 of 436\n\n$ bump-in-the-stack\r\n (I) An implementation approach that places a network security\r\n mechanism inside the system that is to be protected. (Compare:\r\n bump-in-the-wire.)\r\nShirey Informational [Page 42]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Example: IPsec can be implemented inboard, in the protocol stack\r\n of an existing system or existing system design, by placing a new\r\n layer between the existing IP layer and the OSIRM Layer 3 drivers.\r\n Source code access for the existing stack is not required, but the\r\n system that contains the stack does need to be modified [R4301].\r\n $ bump-in-the-wire\r\n (I) An implementation approach that places a network security\r\n mechanism outside of the system that is to be protected. (Compare:\r\n bump-in-the-stack.)\r\n Example: IPsec can be implemented outboard, in a physically\r\n separate device, so that the system that receives the IPsec\r\n protection does not need to be modified at all [R4301]. Military-\r\n grade link encryption has mainly been implemented as bump-in-the-\r\n wire devices.\r\n $ business-case analysis\r\n (N) An extended form of cost-benefit analysis that considers\r\n factors beyond financial metrics, including security factors such\r\n as the requirement for security services, their technical and\r\n programmatic feasibility, their qualitative benefits, and\r\n associated risks. (See: risk analysis.)\r\n $ byte\r\n (I) A fundamental unit of computer storage; the smallest\r\n addressable unit in a computer's architecture. Usually holds one\r\n character of information and, today, usually means eight bits.\r\n (Compare: octet.)\r\n Usage: Understood to be larger than a \"bit\", but smaller than a\r\n \"word\". Although \"byte\" almost always means \"octet\" today, some\r\n computer architectures have had bytes in other sizes (e.g., six\r\n bits, nine bits). Therefore, an STD SHOULD state the number of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 51 of 436\n\nbits in a byte where the term is first used in the STD.\r\n $ C field\r\n (D) See: Compartments field.\r\n $ C1 or C2 computer system\r\n (O) /TCSEC/ See: Tutorial under \"Trusted Computer System\r\n Evaluation Criteria\".\r\n $ CA\r\n (I) See: certification authority.\r\nShirey Informational [Page 43]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ CA certificate\r\n (D) \"A [digital] certificate for one CA issued by another CA.\"\r\n [X509]\r\n Deprecated Definition: IDOCs SHOULD NOT use the term with this\r\n definition; the definition is ambiguous with regard to how the\r\n certificate is constructed and how it is intended to be used.\r\n IDOCs that use this term SHOULD provide a technical definition for\r\n it. (See: certificate profile.)\r\n Tutorial: There is no single, obvious choice for a technical\r\n definition of this term. Different PKIs can use different\r\n certificate profiles, and X.509 provides several choices of how to\r\n issue certificates to CAs. For example, one possible definition is\r\n the following: A v3 X.509 public-key certificate that has a\r\n \"basicConstraints\" extension containing a \"cA\" value of \"TRUE\".\r\n That would specifically indicate that \"the certified public key\r\n may be used to verify certificate signatures\", i.e., that the\r\n private key may be used by a CA.\r\n However, there also are other ways to indicate such usage. The\r\n certificate may have a \"key Usage\" extension that indicates the\r\n purposes for which the public key may be used, and one of the\r\n values that X.509 defines for that extension is \"keyCertSign\", to\r\n indicate that the certificate may be used for verifying a CA's\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 52 of 436\n\nsignature on certificates. If \"keyCertSign\" is present in a\r\n certificate that also has a \"basicConstraints\" extension, then\r\n \"cA\" is set to \"TRUE\" in that extension. Alternatively, a CA could\r\n be issued a certificate in which \"keyCertSign\" is asserted without\r\n \"basicConstraints\" being present; and an entity that acts as a CA\r\n could be issued a certificate with \"keyUsage\" set to other values,\r\n either with or without \"keyCertSign\".\r\n $ CA domain\r\n (N) /PKI/ A security policy domain that \"consists of a CA and its\r\n subjects [i.e., the entities named in the certificates issued by\r\n the CA]. Sometimes referred to as a PKI domain.\" [PAG] (See:\r\n domain.)\r\n $ Caesar cipher\r\n (I) A cipher that is defined for an alphabet of N characters,\r\n A(1), A(2), ..., A(N), and creates cipher text by replacing each\r\n plaintext character A(i) by A(i+K, mod N) for some 0\u003cK\u003cN+1. [Schn]\r\n Examples: (a) During the Gallic wars, Julius Caesar used a cipher\r\n with K=3. In a Caesar cipher with K=3 for the English alphabet, A\r\n is replaced by D, B by E, C by F, ..., W by Z, X by A, Y by B, Z\r\nShirey Informational [Page 44]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n by C. (b) UNIX systems sometimes include \"ROT13\" software that\r\n implements a Caesar cipher with K=13 (i.e., ROTate by 13).\r\n $ call back\r\n (I) An authentication technique for terminals that remotely access\r\n a computer via telephone lines; the host system disconnects the\r\n caller and then reconnects on a telephone number that was\r\n previously authorized for that terminal.\r\n $ CAM\r\n (O) See: Certificate Arbitrator Module.\r\n $ CANEWARE\r\n (O) An end-to-end encryption system for computer data networks\r\n that was developed by the U.S. DoD in the 1980s to provide host-\r\n to-host data confidentiality service for datagrams in OSIRM Layer\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 53 of 436\n\n3. [Roge] (Compare: BLACKER, IPsec.)\r\n Tutorial: Each user host connects to its own bump-in-the-wire\r\n encryption device called a CANEWARE Front End (CFE), through which\r\n the host connects to the subnetwork. CANEWARE uses symmetric\r\n encryption for CFE-to-CFE traffic, but also uses FIREFLY to\r\n establish those session keys. The public-key certificates issued\r\n by the FIREFLY system include credentials for mandatory access\r\n control. For discretionary access control, the system also\r\n includes one or more centralized CANEWARE Control Processors\r\n (CCPs) that connect to the subnetwork, maintain a database for\r\n discretionary access control authorizations, and communicate those\r\n authorizations to assigned sets of CFEs.\r\n The CANEWARE system is MLS in only two of the three ways that\r\n BLACKER is MLS: (a) Like BLACKER BFEs, CFEs form a security\r\n perimeter around a subnetwork, separating user hosts from the\r\n subnetwork, so that the subnetwork can operate at a different\r\n security level than the hosts. (b) Like BLACKER, the CANEWARE\r\n components are trusted to separate datagrams of different security\r\n levels, so that each datagram of a given security level can be\r\n received only by a host that is authorized for that security\r\n level; and thus CANEWARE can separate host communities that\r\n operate at different security levels. (c) Unlike a BFE, the host\r\n side of a CFE is not MLS, and treats all packets received from a\r\n user host as being at the same mandatory security level.\r\n $ capability list\r\n (I) /information system/ A mechanism that implements access\r\n control for a system entity by enumerating the system resources\r\n that the entity is permitted to access and, either implicitly or\r\n explicitly, the access modes granted for each resource. (Compare:\r\nShirey Informational [Page 45]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n access control list, access control matrix, access profile,\r\n capability token.)\r\n $ capability token\r\n (I) A token (usually an unforgeable data object) that gives the\r\n bearer or holder the right to access a system resource. Possession\r\n of the token is accepted by a system as proof that the holder has\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 54 of 436\n\nbeen authorized to access the resource indicated by the token.\r\n (See: attribute certificate, capability list, credential, digital\r\n certificate, ticket, token.)\r\n $ Capability Maturity Model (CMM)\r\n (N) Method for judging the maturity of software processes in an\r\n organization and for identifying crucial practices needed to\r\n increase process maturity. [Chris] (Compare: Common Criteria.)\r\n Tutorial: The CMM does not specify security evaluation criteria\r\n (see: assurance level), but its use may improve security\r\n assurance. The CMM describes principles and practices that can\r\n improve software processes in terms of evolving from ad hoc\r\n processes to disciplined processes. The CMM has five levels:\r\n - Initial: Software processes are ad hoc or chaotic, and few are\r\n well-defined. Success depends on individual effort and heroics.\r\n - Repeatable: Basic project management processes are established\r\n to track cost, schedule, and functionality. Necessary process\r\n discipline is in place to repeat earlier successes on projects\r\n with similar applications.\r\n - Defined: Software process for both management and engineering\r\n activities is documented, standardized, and integrated into a\r\n standard software process for the organization. Each project\r\n uses an approved, tailored version of the organization's\r\n standard process for developing and maintaining software.\r\n - Managed: Detailed measures of software process and product\r\n quality are collected. Both software process and products are\r\n quantitatively understood and controlled.\r\n - Optimizing: Continuous process improvement is enabled by\r\n quantitative feedback from the process and from piloting\r\n innovative ideas and technologies.\r\n $ CAPI\r\n (I) See: cryptographic application programming interface.\r\n $ CAPSTONE\r\n (N) An integrated microcircuit (in MYK-8x series manufactured by\r\n Mykotronx, Inc.) that implements SKIPJACK, KEA, DSA, SHA, and\r\n basic mathematical functions needed to support asymmetric\r\n cryptography; has a non-deterministic random number generator; and\r\n supports key escrow. (See: FORTEZZA. Compare: CLIPPER.)\r\nShirey Informational [Page 46]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 55 of 436\n\n$ card\r\n See: cryptographic card, FORTEZZA, payment card, PC card, smart\r\n card, token.\r\n $ card backup\r\n See: token backup.\r\n $ card copy\r\n See: token copy.\r\n $ card restore\r\n See: token restore.\r\n $ cardholder\r\n 1. (I) An entity to whom or to which a card has been issued.\r\n Usage: Usually refers to a living human being, but might refer (a)\r\n to a position (see: billet, role) in an organization or (b) to an\r\n automated process. (Compare: user.)\r\n 2. (O) /SET/ \"The holder of a valid payment card account and user\r\n of software supporting electronic commerce.\" [SET2] A cardholder\r\n is issued a payment card by an issuer. SET ensures that in the\r\n cardholder's interactions with merchants, the payment card account\r\n information remains confidential. [SET1]\r\n $ cardholder certificate\r\n (O) /SET/ A digital certificate that is issued to a cardholder\r\n upon approval of the cardholder's issuing financial institution\r\n and that is transmitted to merchants with purchase requests and\r\n encrypted payment instructions, carrying assurance that the\r\n account number has been validated by the issuing financial\r\n institution and cannot be altered by a third party. [SET1]\r\n $ cardholder certification authority (CCA)\r\n (O) /SET/ A CA responsible for issuing digital certificates to\r\n cardholders and operated on behalf of a payment card brand, an\r\n issuer, or another party according to brand rules. A CCA maintains\r\n relationships with card issuers to allow for the verification of\r\n cardholder accounts. A CCA does not issue a CRL but does\r\n distribute CRLs issued by root CAs, brand CAs, geopolitical CAs,\r\n and payment gateway CAs. [SET2]\r\n $ CAST\r\n (N) A design procedure for symmetric encryption algorithms, and a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 56 of 436\n\nresulting family of algorithms, invented by Carlisle Adams (C.A.)\r\n and Stafford Tavares (S.T.). [R2144, R2612]\r\nShirey Informational [Page 47]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ category\r\n (I) A grouping of sensitive information items to which a non-\r\n hierarchical restrictive security label is applied to increase\r\n protection of the data. (See: formal access approval. Compare:\r\n compartment, classification.)\r\n $ CAW\r\n (N) See: certification authority workstation.\r\n $ CBC\r\n (N) See: cipher block chaining.\r\n $ CCA\r\n (O) See: cardholder certification authority.\r\n $ CCEP\r\n (O) See: Commercial COMSEC Endorsement Program.\r\n $ CCI\r\n (O) See: Controlled Cryptographic Item.\r\n $ CCITT\r\n (N) Acronym for French translation of International Telephone and\r\n Telegraph Consultative Committee. Now renamed ITU-T.\r\n $ CCM\r\n (N) See: Counter with Cipher Block Chaining-Message Authentication\r\n Code.\r\n $ CERIAS\r\n (O) Purdue University's Center for Education and Research in\r\n Information Assurance and Security, which includes faculty from\r\n multiple schools and departments and takes a multidisciplinary\r\n approach to security problems ranging from technical to ethical,\r\n legal, educational, communicational, linguistic, and economic.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 57 of 436\n\n$ CERT\r\n (I) See: computer emergency response team.\r\n $ certificate\r\n 1. (I) /general English/ A document that attests to the truth of\r\n something or the ownership of something.\r\n 2. (I) /general security/ See: capability token, digital\r\n certificate.\r\n 3. (I) /PKI/ See: attribute certificate, public-key certificate.\r\nShirey Informational [Page 48]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Certificate Arbitrator Module (CAM)\r\n (O) An open-source software module that is designed to be\r\n integrated with an application for routing, replying to, and\r\n otherwise managing and meditating certificate validation requests\r\n between that application and the CAs in the ACES PKI.\r\n $ certificate authority\r\n (D) Synonym for \"certification authority\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it suggests\r\n careless use of the term \"certification authority\", which is\r\n preferred in PKI standards (e.g., [X509, R3280]).\r\n $ certificate chain\r\n (D) Synonym for \"certification path\". (See: trust chain.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it duplicates the\r\n meaning of a standardized term. Instead, use \"certification path\".\r\n $ certificate chain validation\r\n (D) Synonym for \"certificate validation\" or \"path validation\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it duplicates the\r\n meaning of standardized terms and mixes concepts in a potentially\r\n misleading way. Instead, use \"certificate validation\" or \"path\r\n validation\", depending on what is meant. (See: validate vs.\r\n verify.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 58 of 436\n\n$ certificate creation\r\n (I) The act or process by which a CA sets the values of a digital\r\n certificate's data fields and signs it. (See: issue.)\r\n $ certificate expiration\r\n (I) The event that occurs when a certificate ceases to be valid\r\n because its assigned lifetime has been exceeded. (See: certificate\r\n revocation, expire.)\r\n Tutorial: The assigned lifetime of an X.509 certificate is stated\r\n in the certificate itself. (See: validity period.)\r\n $ certificate extension\r\n (I) See: extension.\r\n $ certificate holder\r\n (D) Synonym for the \"subject\" of a digital certificate. (Compare:\r\n certificate owner, certificate user.)\r\nShirey Informational [Page 49]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for the subject of a digital certificate; the term is potentially\r\n ambiguous. For example, the term could be misunderstood as\r\n referring to a system entity or component, such as a repository,\r\n that simply has possession of a copy of the certificate.\r\n $ certificate management\r\n (I) The functions that a CA may perform during the lifecycle of a\r\n digital certificate, including the following:\r\n - Acquire and verify data items to bind into the certificate.\r\n - Encode and sign the certificate.\r\n - Store the certificate in a directory or repository.\r\n - Renew, rekey, and update the certificate.\r\n - Revoke the certificate and issue a CRL.\r\n (See: archive management, certificate management, key management,\r\n security architecture, token management.)\r\n $ certificate management authority (CMA)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 59 of 436\n\n(D) /U.S. DoD/ Used to mean either a CA or an RA. [DoD7, SP32]\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is\r\n potentially ambiguous, such as in a context involving ICRLs.\r\n Instead, use CA, RA, or both, depending on what is meant.\r\n $ certificate owner\r\n (D) Synonym for the \"subject\" of a digital certificate. (Compare:\r\n certificate holder, certificate user.)\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for the subject of a digital certificate; the term is potentially\r\n ambiguous. For example, the term could refer to a system entity,\r\n such as a corporation, that has purchased a certificate to operate\r\n equipment, such as a Web server.\r\n $ certificate path\r\n (D) Synonym for \"certification path\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it suggests\r\n careless use of \"certification path\", which is preferred in PKI\r\n standards (e.g., [X509, R3280]).\r\n $ certificate policy\r\n (I) \"A named set of rules that indicates the applicability of a\r\n certificate to a particular community and/or class of application\r\n with common security requirements.\" [X509] (Compare: CPS, security\r\n policy.)\r\nShirey Informational [Page 50]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Example: U.S. DoD's certificate policy [DoD7] defined four classes\r\n (i.e., assurance levels) for X.509 public-key certificates and\r\n defines the applicability of those classes. (See: class 2.)\r\n Tutorial: A certificate policy can help a certificate user to\r\n decide whether a certificate should be trusted in a particular\r\n application. \"For example, a particular certificate policy might\r\n indicate applicability of a type of certificate for the\r\n authentication of electronic data interchange transactions for the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 60 of 436\n\ntrading of goods within a given price range.\" [R3647]\r\n A v3 X.509 public-key certificate may have a \"certificatePolicies\"\r\n extension that lists certificate policies, recognized by the\r\n issuing CA, that apply to the certificate and govern its use. Each\r\n policy is denoted by an object identifier and may optionally have\r\n certificate policy qualifiers. (See: certificate profile.)\r\n Each SET certificate specifies at least one certificate policy,\r\n that of the SET root CA. SET uses certificate policy qualifiers to\r\n point to the actual policy statement and to add qualifying\r\n policies to the root policy. (See: SET qualifier.)\r\n $ certificate policy qualifier\r\n (I) Information that pertains to a certificate policy and is\r\n included in a \"certificatePolicies\" extension in a v3 X.509\r\n public-key certificate.\r\n $ certificate profile\r\n (I) A specification (e.g., [DoD7, R3280]) of the format and\r\n semantics of public-key certificates or attribute certificates,\r\n constructed for use in a specific application context by selecting\r\n from among options offered by a broader standard. (Compare:\r\n protection profile.)\r\n $ certificate reactivation\r\n (I) The act or process by which a digital certificate, that a CA\r\n has designated for revocation but not yet listed on a CRL, is\r\n returned to the valid state.\r\n $ certificate rekey\r\n 1. (I) The act or process by which an existing public-key\r\n certificate has its key value changed by issuing a new certificate\r\n with a different (usually new) public key. (See: certificate\r\n renewal, certificate update, rekey.)\r\n Tutorial: For an X.509 public-key certificate, the essence of\r\n rekey is that the subject stays the same and a new public key is\r\n bound to that subject. Other changes are made, and the old\r\nShirey Informational [Page 51]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 61 of 436\n\ncertificate is revoked, only as required by the PKI and CPS in\r\n support of the rekey. If changes go beyond that, the process is a\r\n \"certificate update\".\r\n 2. (O) /MISSI/ The act or process by which a MISSI CA creates a\r\n new X.509 public-key certificate that is identical to the old one,\r\n except the new one has (a) a new, different KEA key or (b) a new,\r\n different DSS key or (c) new, different KEA and DSS keys. The new\r\n certificate also has a different serial number and may have a\r\n different validity period. A new key creation date and maximum key\r\n lifetime period are assigned to each newly generated key. If a new\r\n KEA key is generated, that key is assigned a new KMID. The old\r\n certificate remains valid until it expires, but may not be further\r\n renewed, rekeyed, or updated.\r\n $ certificate renewal\r\n (I) The act or process by which the validity of the binding\r\n asserted by an existing public-key certificate is extended in time\r\n by issuing a new certificate. (See: certificate rekey, certificate\r\n update.)\r\n Tutorial: For an X.509 public-key certificate, this term means\r\n that the validity period is extended (and, of course, a new serial\r\n number is assigned) but the binding of the public key to the\r\n subject and to other data items stays the same. The other data\r\n items are changed, and the old certificate is revoked, only as\r\n required by the PKI and CPS to support the renewal. If changes go\r\n beyond that, the process is a \"certificate rekey\" or \"certificate\r\n update\".\r\n $ certificate request\r\n (D) Synonym for \"certification request\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it suggests\r\n careless use of the term \"certification request\", which is\r\n preferred in PKI standards (e.g., see PKCS #10).\r\n $ certificate revocation\r\n (I) The event that occurs when a CA declares that a previously\r\n valid digital certificate issued by that CA has become invalid;\r\n usually stated with an effective date.\r\n Tutorial: In X.509, a revocation is announced to potential\r\n certificate users by issuing a CRL that mentions the certificate.\r\n Revocation and listing on a CRL is only necessary prior to the\r\n certificate's scheduled expiration.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 62 of 436\n\nShirey Informational [Page 52]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ certificate revocation list (CRL)\r\n 1. (I) A data structure that enumerates digital certificates that\r\n have been invalidated by their issuer prior to when they were\r\n scheduled to expire. (See: certificate expiration, delta CRL,\r\n X.509 certificate revocation list.)\r\n 2. (O) \"A signed list indicating a set of certificates that are no\r\n longer considered valid by the certificate issuer. In addition to\r\n the generic term CRL, some specific CRL types are defined for CRLs\r\n that cover particular scopes.\" [X509]\r\n $ certificate revocation tree\r\n (N) A mechanism for distributing notices of certificate\r\n revocations; uses a tree of hash results that is signed by the\r\n tree's issuer. Offers an alternative to issuing a CRL, but is not\r\n supported in X.509. (See: certificate status responder.)\r\n $ certificate serial number\r\n 1. (I) An integer value that (a) is associated with, and may be\r\n carried in, a digital certificate; (b) is assigned to the\r\n certificate by the certificate's issuer; and (c) is unique among\r\n all the certificates produced by that issuer.\r\n 2. (O) \"An integer value, unique within the issuing CA, [that] is\r\n unambiguously associated with a certificate issued by that CA.\"\r\n [X509]\r\n $ certificate status authority\r\n (D) /U.S. DoD/ \"A trusted entity that provides on-line\r\n verification to a Relying Party of a subject certificate's\r\n trustworthiness [should instead say 'validity'], and may also\r\n provide additional attribute information for the subject\r\n certificate.\" [DoD7]\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is not\r\n widely accepted; instead, use \"certificate status responder\" or\r\n \"OCSP server\", or otherwise explain what is meant.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 63 of 436\n\n$ certificate status responder\r\n (N) /FPKI/ A trusted online server that acts for a CA to provide\r\n authenticated certificate status information to certificate users\r\n [FPKI]. Offers an alternative to issuing a CR. (See: certificate\r\n revocation tree, OCSP.)\r\n $ certificate update\r\n (I) The act or process by which non-key data items bound in an\r\n existing public-key certificate, especially authorizations granted\r\nShirey Informational [Page 53]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n to the subject, are changed by issuing a new certificate. (See:\r\n certificate rekey, certificate renewal.)\r\n Usage: For an X.509 public-key certificate, the essence of this\r\n process is that fundamental changes are made in the data that is\r\n bound to the public key, such that it is necessary to revoke the\r\n old certificate. (Otherwise, the process is only a \"certificate\r\n rekey\" or \"certificate renewal\".)\r\n $ certificate user\r\n 1. (I) A system entity that depends on the validity of information\r\n (such as another entity's public key value) provided by a digital\r\n certificate. (See: relying party. Compare: /digital certificate/\r\n subject.)\r\n Usage: The depending entity may be a human being or an\r\n organization, or a device or process controlled by a human or\r\n organization. (See: user.)\r\n 2. (O) \"An entity that needs to know, with certainty, the public\r\n key of another entity.\" [X509]\r\n 3. (D) Synonym for \"subject\" of a digital certificate.\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 3; the term could be confused with one of the other two\r\n definitions given above.\r\n $ certificate validation\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 64 of 436\n\n1. (I) An act or process by which a certificate user establishes\r\n that the assertions made by a digital certificate can be trusted.\r\n (See: valid certificate, validate vs. verify.)\r\n 2. (O) \"The process of ensuring that a certificate was valid at a\r\n given time, including possibly the construction and processing of\r\n a certification path [R4158], and ensuring that all certificates\r\n in that path were valid (i.e. were not expired or revoked) at that\r\n given time.\" [X509]\r\n Tutorial: To validate a certificate, a certificate user checks\r\n that the certificate is properly formed and signed and is\r\n currently in force:\r\n - Checks the syntax and semantics: Parses the certificate's\r\n syntax and interprets its semantics, applying rules specified\r\n for and by its data fields, such as for critical extensions in\r\n an X.509 certificate.\r\nShirey Informational [Page 54]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - Checks the signature: Uses the issuer's public key to verify\r\n the digital signature of the CA who issued the certificate in\r\n question. If the verifier obtains the issuer's public key from\r\n the issuer's own public-key certificate, that certificate\r\n should be validated, too. That validation may lead to yet\r\n another certificate to be validated, and so on. Thus, in\r\n general, certificate validation involves discovering and\r\n validating a certification path.\r\n - Checks currency and revocation: Verifies that the certificate\r\n is currently in force by checking that the current date and\r\n time are within the validity period (if that is specified in\r\n the certificate) and that the certificate is not listed on a\r\n CRL or otherwise announced as invalid. (The CRLs also must be\r\n checked by a similar validation process.)\r\n $ certification\r\n 1. (I) /information system/ Comprehensive evaluation (usually made\r\n in support of an accreditation action) of an information system's\r\n technical security features and other safeguards to establish the\r\n extent to which the system's design and implementation meet a set\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 65 of 436\n\nof specified security requirements. [C4009, FP102, SP37] (See:\r\n accreditation. Compare: evaluation.)\r\n 2. (I) /digital certificate/ The act or process of vouching for\r\n the truth and accuracy of the binding between data items in a\r\n certificate. (See: certify.)\r\n 3. (I) /PKI/ The act or process of vouching for the ownership of a\r\n public key by issuing a public-key certificate that binds the key\r\n to the name of the entity that possesses the matching private key.\r\n Besides binding a key with a name, a public-key certificate may\r\n bind those items with other restrictive or explanatory data items.\r\n (See: X.509 public-key certificate.)\r\n 4. (O) /SET/ \"The process of ascertaining that a set of\r\n requirements or criteria has been fulfilled and attesting to that\r\n fact to others, usually with some written instrument. A system\r\n that has been inspected and evaluated as fully compliant with the\r\n SET protocol by duly authorized parties and process would be said\r\n to have been certified compliant.\" [SET2]\r\n $ certification authority (CA)\r\n 1. (I) An entity that issues digital certificates (especially\r\n X.509 certificates) and vouches for the binding between the data\r\n items in a certificate.\r\nShirey Informational [Page 55]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) \"An authority trusted by one or more users to create and\r\n assign certificates. Optionally the certification authority may\r\n create the user's keys.\" [X509]\r\n Tutorial: Certificate users depend on the validity of information\r\n provided by a certificate. Thus, a CA should be someone that\r\n certificate users trust and that usually holds an official\r\n position created and granted power by a government, a corporation,\r\n or some other organization. A CA is responsible for managing the\r\n life cycle of certificates (see: certificate management) and,\r\n depending on the type of certificate and the CPS that applies, may\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 66 of 436\n\nbe responsible for the lifecycle of key pairs associated with the\r\n certificates (see: key management).\r\n $ certification authority workstation (CAW)\r\n (N) A computer system that enables a CA to issue digital\r\n certificates and supports other certificate management functions\r\n as required.\r\n $ certification hierarchy\r\n 1. (I) A tree-structured (loop-free) topology of relationships\r\n between CAs and the entities to whom the CAs issue public-key\r\n certificates. (See: hierarchical PKI, hierarchy management.)\r\n Tutorial: In this structure, one CA is the top CA, the highest\r\n level of the hierarchy. (See: root, top CA.) The top CA may issue\r\n public-key certificates to one or more additional CAs that form\r\n the second-highest level. Each of these CAs may issue certificates\r\n to more CAs at the third-highest level, and so on. The CAs at the\r\n second-lowest level issue certificates only to non-CA entities\r\n that form the lowest level (see: end entity). Thus, all\r\n certification paths begin at the top CA and descend through zero\r\n or more levels of other CAs. All certificate users base path\r\n validations on the top CA's public key.\r\n 2. (I) /PEM/ A certification hierarchy for PEM has three levels of\r\n CAs [R1422]:\r\n - The highest level is the \"Internet Policy Registration\r\n Authority\".\r\n - A CA at the second-highest level is a \"policy certification\r\n authority\".\r\n - A CA at the third-highest level is a \"certification authority\".\r\n 3. (O) /MISSI/ A certification hierarchy for MISSI has three or\r\n four levels of CAs:\r\n - A CA at the highest level, the top CA, is a \"policy approving\r\n authority\".\r\nShirey Informational [Page 56]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - A CA at the second-highest level is a \"policy creation\r\n authority\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 67 of 436\n\n- A CA at the third-highest level is a local authority called a\r\n \"certification authority\".\r\n - A CA at the fourth-highest (optional) level is a \"subordinate\r\n certification authority\".\r\n 4. (O) /SET/ A certification hierarchy for SET has three or four\r\n levels of CAs:\r\n - The highest level is a \"SET root CA\".\r\n - A CA at the second-highest level is a \"brand certification\r\n authority\".\r\n - A CA at the third-highest (optional) level is a \"geopolitical\r\n certification authority\".\r\n - A CA at the fourth-highest level is a \"cardholder CA\", a\r\n \"merchant CA\", or a \"payment gateway CA\".\r\n $ certification path\r\n 1. (I) A linked sequence of one or more public-key certificates,\r\n or one or more public-key certificates and one attribute\r\n certificate, that enables a certificate user to verify the\r\n signature on the last certificate in the path, and thus enables\r\n the user to obtain (from that last certificate) a certified public\r\n key, or certified attributes, of the system entity that is the\r\n subject of that last certificate. (See: trust anchor, certificate\r\n validation, valid certificate.)\r\n 2. (O) \"An ordered sequence of certificates of objects in the\r\n [X.500 Directory Information Tree] which, together with the public\r\n key of the initial object in the path, can be processed to obtain\r\n that of the final object in the path.\" [R3647, X509]\r\n Tutorial: The list is \"linked\" in the sense that the digital\r\n signature of each certificate (except possibly the first) is\r\n verified by the public key contained in the preceding certificate;\r\n i.e., the private key used to sign a certificate and the public\r\n key contained in the preceding certificate form a key pair that\r\n has previously been bound to the authority that signed.\r\n The path is the \"list of certificates needed to [enable] a\r\n particular user to obtain the public key [or attributes] of\r\n another [user].\" [X509] Here, the word \"particular\" points out\r\n that a certification path that can be validated by one certificate\r\n user might not be able to be validated by another. That is because\r\n either the first certificate needs to be a trusted certificate or\r\n the signature on the first certificate needs to be verifiable by a\r\n trusted key (e.g., a root key), but such trust is established only\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 68 of 436\n\nShirey Informational [Page 57]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n relative to a \"particular\" (i.e., specific) user, not absolutely\r\n for all users.\r\n $ certification policy\r\n (D) Synonym for either \"certificate policy\" or \"certification\r\n practice statement\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n either of those terms; that would be duplicative and would mix\r\n concepts in a potentially misleading way. Instead, use either\r\n \"certificate policy\" or \"certification practice statement\",\r\n depending on what is meant.\r\n $ certification practice statement (CPS)\r\n (I) \"A statement of the practices which a certification authority\r\n employs in issuing certificates.\" [DSG, R3647] (See: certificate\r\n policy.)\r\n Tutorial: A CPS is a published security policy that can help a\r\n certificate user to decide whether a certificate issued by a\r\n particular CA can be trusted enough to use in a particular\r\n application. A CPS may be (a) a declaration by a CA of the details\r\n of the system and practices it uses in its certificate management\r\n operations, (b) part of a contract between the CA and an entity to\r\n whom a certificate is issued, (c) a statute or regulation\r\n applicable to the CA, or (d) a combination of these types\r\n involving multiple documents. [DSG]\r\n A CPS is usually more detailed and procedurally oriented than a\r\n certificate policy. A CPS applies to a particular CA or CA\r\n community, while a certificate policy applies across CAs or\r\n communities. A CA with its single CPS may support multiple\r\n certificate policies, which may be used for different application\r\n purposes or by different user communities. On the other hand,\r\n multiple CAs, each with a different CPS, may support the same\r\n certificate policy. [R3647]\r\n $ certification request\r\n (I) An algorithm-independent transaction format (e.g., PKCS #10,\r\n RFC 4211) that contains a DN, and a public key or, optionally, a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 69 of 436\n\nset of attributes, collectively signed by the entity requesting\r\n certification, and sent to a CA, which transforms the request to\r\n an X.509 public-key certificate or another type of certificate.\r\n $ certify\r\n 1. (I) Issue a digital certificate and thus vouch for the truth,\r\n accuracy, and binding between data items in the certificate (e.g.,\r\n \"X.509 public-key certificate\"), such as the identity of the\r\nShirey Informational [Page 58]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n certificate's subject and the ownership of a public key. (See:\r\n certification.)\r\n Usage: To \"certify a public key\" means to issue a public-key\r\n certificate that vouches for the binding between the certificate's\r\n subject and the key.\r\n 2. (I) The act by which a CA uses measures to verify the truth,\r\n accuracy, and binding between data items in a digital certificate.\r\n Tutorial: A description of the measures used for verification\r\n should be included in the CA's CPS.\r\n $ CFB\r\n (N) See: cipher feedback.\r\n $ chain\r\n (D) See: trust chain.\r\n $ Challenge Handshake Authentication Protocol (CHAP)\r\n (I) A peer entity authentication method (employed by PPP and other\r\n protocols, e.g., RFC 3720) that uses a randomly generated\r\n challenge and requires a matching response that depends on a\r\n cryptographic hash of some combination of the challenge and a\r\n secret key. [R1994] (See: challenge-response, PAP.)\r\n $ challenge-response\r\n (I) An authentication process that verifies an identity by\r\n requiring correct authentication information to be provided in\r\n response to a challenge. In a computer system, the authentication\r\n information is usually a value that is required to be computed in\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 70 of 436\n\nresponse to an unpredictable challenge value, but it might be just\r\n a password.\r\n $ Challenge-Response Authentication Mechanism (CRAM)\r\n (I) /IMAP4/ A mechanism [R2195], intended for use with IMAP4\r\n AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104]\r\n to authenticate itself to an IMAP4 server. (See: POP3 APOP.)\r\n Tutorial: The server includes a unique time stamp in its ready\r\n response to the client. The client replies with the client's name\r\n and the hash result of applying MD5 to a string formed from\r\n concatenating the time stamp with a shared secret that is known\r\n only to the client and the server.\r\n $ channel\r\n 1. (I) An information transfer path within a system. (See: covert\r\n channel.)\r\nShirey Informational [Page 59]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) \"A subdivision of the physical medium allowing possibly\r\n shared independent uses of the medium.\" (RFC 3753)\r\n $ channel capacity\r\n (I) The total capacity of a link to carry information; usually\r\n expressed in bits per second. (RFC 3753) (Compare: bandwidth.)\r\n Tutorial: Within a given bandwidth, the theoretical maximum\r\n channel capacity is given by Shannon's Law. The actual channel\r\n capacity is determined by the bandwidth, the coding system used,\r\n and the signal-to-noise ratio.\r\n $ CHAP\r\n (I) See: Challenge Handshake Authentication Protocol.\r\n $ checksum\r\n (I) A value that (a) is computed by a function that is dependent\r\n on the contents of a data object and (b) is stored or transmitted\r\n together with the object, for detecting changes in the data. (See:\r\n cyclic redundancy check, data integrity service, error detection\r\n code, hash, keyed hash, parity bit, protected checksum.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 71 of 436\n\nTutorial: To gain confidence that a data object has not been\r\n changed, an entity that later uses the data can independently\r\n recompute the checksum value and compare the result with the value\r\n that was stored or transmitted with the object.\r\n Computer systems and networks use checksums (and other mechanisms)\r\n to detect accidental changes in data. However, active wiretapping\r\n that changes data could also change an accompanying checksum to\r\n match the changed data. Thus, some checksum functions by\r\n themselves are not good countermeasures for active attacks. To\r\n protect against active attacks, the checksum function needs to be\r\n well-chosen (see: cryptographic hash), and the checksum result\r\n needs to be cryptographically protected (see: digital signature,\r\n keyed hash).\r\n $ Chinese wall policy\r\n (I) A security policy to prevent conflict of interest caused by an\r\n entity (e.g., a consultant) interacting with competing firms.\r\n (See: Brewer-Nash model.)\r\n Tutorial: All information is categorized into mutually exclusive\r\n conflict-of-interest classes I(1), I(2), ..., I(M), and each firm\r\n F(1), F(2), ..., F(N) belongs to exactly one class. The policy\r\n states that if a consultant has access to class I(i) information\r\n from a firm in that class, then the consultant may not access\r\n information from another firm in that same class, but may access\r\nShirey Informational [Page 60]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n information from another firm that is in a different class. Thus,\r\n the policy creates a barrier to communication between firms that\r\n are in the same conflict-of-interest class. Brewer and Nash\r\n modeled enforcement of this policy [BN89], including dealing with\r\n policy violations that could occur because two or more consultants\r\n work for the same firm.\r\n $ chosen-ciphertext attack\r\n (I) A cryptanalysis technique in which the analyst tries to\r\n determine the key from knowledge of plain text that corresponds to\r\n cipher text selected (i.e., dictated) by the analyst.\r\n $ chosen-plaintext attack\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 72 of 436\n\n(I) A cryptanalysis technique in which the analyst tries to\r\n determine the key from knowledge of cipher text that corresponds\r\n to plain text selected (i.e., dictated) by the analyst.\r\n $ CIAC\r\n (O) See: Computer Incident Advisory Capability.\r\n $ CIK\r\n (N) See: cryptographic ignition key.\r\n $ cipher\r\n (I) A cryptographic algorithm for encryption and decryption.\r\n $ cipher block chaining (CBC)\r\n (N) A block cipher mode that enhances ECB mode by chaining\r\n together blocks of cipher text it produces. [FP081] (See: block\r\n cipher, [R1829], [R2405], [R2451], [SP38A].)\r\n Tutorial: This mode operates by combining (exclusive OR-ing) the\r\n algorithm's ciphertext output block with the next plaintext block\r\n to form the next input block for the algorithm.\r\n $ cipher feedback (CFB)\r\n (N) A block cipher mode that enhances ECB mode by chaining\r\n together the blocks of cipher text it produces and operating on\r\n plaintext segments of variable length less than or equal to the\r\n block length. [FP081] (See: block cipher, [SP38A].)\r\n Tutorial: This mode operates by using the previously generated\r\n ciphertext segment as the algorithm's input (i.e., by \"feeding\r\n back\" the cipher text) to generate an output block, and then\r\n combining (exclusive OR-ing) that output block with the next\r\n plaintext segment (block length or less) to form the next\r\n ciphertext segment.\r\nShirey Informational [Page 61]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ cipher text\r\n 1. (I) /noun/ Data that has been transformed by encryption so that\r\n its semantic information content (i.e., its meaning) is no longer\r\n intelligible or directly available. (See: ciphertext. Compare:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 73 of 436\n\nclear text, plain text.)\r\n 2. (O) \"Data produced through the use of encipherment. The\r\n semantic content of the resulting data is not available.\"\r\n [I7498-2]\r\n $ ciphertext\r\n 1. (O) /noun/ Synonym for \"cipher text\" [I7498-2].\r\n 2. (I) /adjective/ Referring to cipher text. Usage: Commonly used\r\n instead of \"cipher-text\". (Compare: cleartext, plaintext.)\r\n $ ciphertext auto-key (CTAK)\r\n (D) \"Cryptographic logic that uses previous cipher text to\r\n generate a key stream.\" [C4009, A1523] (See: KAK.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is neither\r\n well-known nor precisely defined. Instead, use terms associated\r\n with modes that are defined in standards, such as CBC, CFB, and\r\n OFB.\r\n $ ciphertext-only attack\r\n (I) A cryptanalysis technique in which the analyst tries to\r\n determine the key solely from knowledge of intercepted cipher text\r\n (although the analyst may also know other clues, such as the\r\n cryptographic algorithm, the language in which the plain text was\r\n written, the subject matter of the plain text, and some probable\r\n plaintext words.)\r\n $ ciphony\r\n (O) The process of encrypting audio information.\r\n $ CIPSO\r\n (I) See: Common IP Security Option.\r\n $ CKL\r\n (I) See: compromised key list.\r\n $ Clark-Wilson model\r\n (N) A security model [Clark] to maintain data integrity in the\r\n commercial world. (Compare: Bell-LaPadula model.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 74 of 436\n\nShirey Informational [Page 62]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ class 2, 3, 4, 5\r\n (O) /U.S. DoD/ Assurance levels for PKIs, and for X.509 public-key\r\n certificates issued by a PKI. [DoD7] (See: \"first law\" under\r\n \"Courtney's laws\".)\r\n - \"Class 2\": Intended for applications handling unclassified,\r\n low-value data in minimally or moderately protected\r\n environments.\r\n - \"Class 3\": Intended for applications handling unclassified,\r\n medium-value data in moderately protected environments, or\r\n handling unclassified or high-value data in highly protected\r\n environments, and for discretionary access control of\r\n classified data in highly protected environments.\r\n - \"Class 4\": Intended for applications handling unclassified,\r\n high-value data in minimally protected environments.\r\n - \"Class 5\": Intended for applications handling classified data\r\n in minimally protected environments, and for authentication of\r\n material that would affect the security of classified systems.\r\n The environments are defined as follows:\r\n - \"Highly protected environment\": Networks that are protected\r\n either with encryption devices approved by NSA for protection\r\n of classified data or via physical isolation, and that are\r\n certified for processing system-high classified data, where\r\n exposure of unencrypted data is limited to U.S. citizens\r\n holding appropriate security clearances.\r\n - \"Moderately protected environment\":\r\n -- Physically isolated unclassified, unencrypted networks in\r\n which access is restricted based on legitimate need.\r\n -- Networks protected by NSA-approved, type 1 encryption,\r\n accessible by U.S.-authorized foreign nationals.\r\n - \"Minimally protected environments\": Unencrypted networks\r\n connected to either the Internet or NIPRNET, either directly or\r\n via a firewall.\r\n $ Class A1, B3, B2, B1, C2, or C1 computer system\r\n (O) /TCSEC/ See: Tutorial under \"Trusted Computer System\r\n Evaluation Criteria\".\r\n $ classification\r\n 1. (I) A grouping of classified information to which a\r\n hierarchical, restrictive security label is applied to increase\r\n protection of the data from unauthorized disclosure. (See:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 75 of 436\n\naggregation, classified, data confidentiality service. Compare:\r\n category, compartment.)\r\n 2. (I) An authorized process by which information is determined to\r\n be classified and assigned to a security level. (Compare:\r\n declassification.)\r\nShirey Informational [Page 63]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: Usually understood to involve data confidentiality, but\r\n IDOCs SHOULD make this clear when data also is sensitive in other\r\n ways and SHOULD use other terms for those other sensitivity\r\n concepts. (See: sensitive information, data integrity.)\r\n $ classification label\r\n (I) A security label that tells the degree of harm that will\r\n result from unauthorized disclosure of the labeled data, and may\r\n also tell what countermeasures are required to be applied to\r\n protect the data from unauthorized disclosure. Example: IPSO.\r\n (See: classified, data confidentiality service. Compare: integrity\r\n label.)\r\n Usage: Usually understood to involve data confidentiality, but\r\n IDOCs SHOULD make this clear when data also is sensitive in other\r\n ways and SHOULD use other terms for those other sensitivity\r\n concepts. (See: sensitive information, data integrity.)\r\n $ classification level\r\n (I) A hierarchical level of protection (against unauthorized\r\n disclosure) that is required to be applied to certain classified\r\n data. (See: classified. Compare: security level.)\r\n Usage: Usually understood to involve data confidentiality, but\r\n IDOCs SHOULD make this clear when data also is sensitive in other\r\n ways and SHOULD use other terms for those other sensitivity\r\n concepts. (See: sensitive information, data integrity.)\r\n $ classified\r\n 1. (I) Refers to information (stored or conveyed, in any form)\r\n that is formally required by a security policy to receive data\r\n confidentiality service and to be marked with a security label\r\n (which, in some cases, might be implicit) to indicate its\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 76 of 436\n\nprotected status. (See: classify, collateral information, SAP,\r\n security level. Compare: unclassified.)\r\n Usage: Usually understood to involve data confidentiality, but\r\n IDOCs SHOULD make this clear when data also is sensitive in other\r\n ways and SHOULD use other terms for those other sensitivity\r\n concepts. (See: sensitive information, data integrity.)\r\n Mainly used by national governments, especially by the military,\r\n but the underlying concept also applies outside of governments.\r\n 2. (O) /U.S. Government/ \"Information that has been determined\r\n pursuant to Executive Order 12958 or any predecessor Order, or by\r\n the Atomic Energy Act of 1954, as amended, to require protection\r\nShirey Informational [Page 64]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n against unauthorized disclosure and is marked to indicate its\r\n classified status.\" [C4009]\r\n $ classify\r\n (I) To officially designate an information item or type of\r\n information as being classified and assigned to a specific\r\n security level. (See: classified, declassify, security level.)\r\n $ clean system\r\n (I) A computer system in which the operating system and\r\n application system software and files have been freshly installed\r\n from trusted software distribution media. (Compare: secure state.)\r\n $ clear\r\n (D) /verb/ Synonym for \"erase\". [C4009]\r\n Deprecated Definition: IDOCs SHOULD NOT use the term with this\r\n definition; that could be confused with \"clear text\" in which\r\n information is directly recoverable.\r\n $ clear text\r\n 1. (I) /noun/ Data in which the semantic information content\r\n (i.e., the meaning) is intelligible or is directly available,\r\n i.e., not encrypted. (See: cleartext, in the clear. Compare:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 77 of 436\n\ncipher text, plain text.)\r\n 2. (O) /noun/ \"Intelligible data, the semantic content of which is\r\n available.\" [I7498-2]\r\n 3. (D) /noun/ Synonym for \"plain text\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"plain text\", because the plain text that is input to an\r\n encryption operation may itself be cipher text that was output\r\n from a previous encryption operation. (See: superencryption.)\r\n $ clearance\r\n See: security clearance.\r\n $ clearance level\r\n (I) The security level of information to which a security\r\n clearance authorizes a person to have access.\r\n $ cleartext\r\n 1. (O) /noun/ Synonym for \"clear text\" [I7498-2].\r\n 2. (I) /adjective/ Referring to clear text. Usage: Commonly used\r\n instead of \"clear-text\". (Compare: ciphertext, plaintext.)\r\nShirey Informational [Page 65]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 3. (D) /adjective/ Synonym for \"plaintext\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"plaintext\", because the plaintext data that is input to an\r\n encryption operation may itself be ciphertext data that was output\r\n from a previous encryption operation. (See: superencryption.)\r\n $ CLEF\r\n (N) See: commercially licensed evaluation facility.\r\n $ client\r\n (I) A system entity that requests and uses a service provided by\r\n another system entity, called a \"server\". (See: server.)\r\n Tutorial: Usually, it is understood that the client and server are\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 78 of 436\n\nautomated components of the system, and the client makes the\r\n request on behalf of a human user. In some cases, the server may\r\n itself be a client of some other server.\r\n $ client-server system\r\n (I) A distributed system in which one or more entities, called\r\n clients, request a specific service from one or more other\r\n entities, called servers, that provide the service to the clients.\r\n Example: The Word Wide Web, in which component servers provide\r\n information that is requested by component clients called\r\n \"browsers\".\r\n $ CLIPPER\r\n (N) An integrated microcircuit (in MYK-7x series manufactured by\r\n Mykotronx, Inc.) that implements SKIPJACK, has a non-deterministic\r\n random number generator, and supports key escrow. (See: Escrowed\r\n Encryption Standard. Compare: CLIPPER.)\r\n Tutorial: The chip was mainly intended for protecting\r\n telecommunications over the public switched network. The key\r\n escrow scheme for the chip involves a SKIPJACK key that is common\r\n to all chips and that protects the unique serial number of the\r\n chip, and a second SKIPJACK key unique to the chip that protects\r\n all data encrypted by the chip. The second key is escrowed as\r\n split key components held by NIST and the U.S. Treasury\r\n Department.\r\n $ closed security environment\r\n (O) /U.S. DoD/ A system environment that meets both of the\r\n following conditions: (a) Application developers (including\r\n maintainers) have sufficient clearances and authorizations to\r\n provide an acceptable presumption that they have not introduced\r\nShirey Informational [Page 66]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n malicious logic. (b) Configuration control provides sufficient\r\n assurance that system applications and the equipment they run on\r\n are protected against the introduction of malicious logic prior to\r\n and during the operation of applications. [NCS04] (See: \"first\r\n law\" under \"Courtney's laws\". Compare: open security environment.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 79 of 436\n\n$ CMA\r\n (D) See: certificate management authority.\r\n $ CMAC\r\n (N) A message authentication code [SP38B] that is based on a\r\n symmetric block cipher. (See: block cipher.)\r\n Derivation: Cipher-based MAC. (Compare: HMAC.)\r\n Tutorial: Because CMAC is based on approved, symmetric-key block\r\n ciphers, such as AES, CMAC can be considered a mode of operation\r\n for those block ciphers. (See: mode of operation.)\r\n $ CMCS\r\n (O) See: COMSEC Material Control System.\r\n $ CMM\r\n (N) See: Capability Maturity Model.\r\n $ CMS\r\n (I) See: Cryptographic Message Syntax.\r\n $ code\r\n 1. (I) A system of symbols used to represent information, which\r\n might originally have some other representation. Examples: ASCII,\r\n BER, country code, Morse code. (See: encode, object code, source\r\n code.)\r\n Deprecated Abbreviation: To avoid confusion with definition 1,\r\n IDOCs SHOULD NOT use \"code\" as an abbreviation of \"country code\",\r\n \"cyclic redundancy code\", \"Data Authentication Code\", \"error\r\n detection code\", or \"Message Authentication Code\". To avoid\r\n misunderstanding, use the fully qualified term in these other\r\n cases, at least at the point of first usage.\r\n 2. (I) /cryptography/ An encryption algorithm based on\r\n substitution; i.e., a system for providing data confidentiality by\r\n using arbitrary groups (called \"code groups\") of letters, numbers,\r\n or symbols to represent units of plain text of varying length.\r\n (See: codebook, cryptography.)\r\nShirey Informational [Page 67]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 80 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Usage: To avoid confusion with definition 1, IDOCs\r\n SHOULD NOT use \"code\" as a synonym for any of the following terms:\r\n (a) \"cipher\", \"hash\", or other words that mean \"a cryptographic\r\n algorithm\"; (b) \"cipher text\"; or (c) \"encrypt\", \"hash\", or other\r\n words that refer to applying a cryptographic algorithm.\r\n 3. (I) An algorithm based on substitution, but used to shorten\r\n messages rather than to conceal their content.\r\n 4. (I) /computer programming/ To write computer software. (See:\r\n object code, source code.)\r\n Deprecated Abbreviation: To avoid confusion with definition 1,\r\n IDOCs SHOULD NOT use \"code\" as an abbreviation of \"object code\" or\r\n \"source code\". To avoid misunderstanding, use the fully qualified\r\n term in these other cases, at least at the point of first usage.\r\n $ code book\r\n 1. (I) Document containing a systematically arranged list of\r\n plaintext units and their ciphertext equivalents. [C4009]\r\n 2. (I) An encryption algorithm that uses a word substitution\r\n technique. [C4009] (See: code, ECB.)\r\n $ code signing\r\n (I) A security mechanism that uses a digital signature to provide\r\n data integrity and data origin authentication for software that is\r\n being distributed for use. (See: mobile code, trusted\r\n distribution.)\r\n Tutorial: In some cases, the signature on a software module may\r\n imply some assertion that the signer makes about the software. For\r\n example, a signature may imply that the software has been\r\n designed, developed, or tested according to some criterion.\r\n $ code word\r\n (O) /U.S. Government/ A single word that is used as a security\r\n label (usually applied to classified information) but which itself\r\n has a classified meaning. (See: classified, /U.S. Government/\r\n security label.)\r\n $ COI\r\n (I) See: community of interest.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 81 of 436\n\n$ cold start\r\n (N) /cryptographic module/ A procedure for initially keying\r\n cryptographic equipment. [C4009]\r\nShirey Informational [Page 68]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ collateral information\r\n (O) /U.S. Government/ Information that is classified but is not\r\n required to be protected by an SAP. (See: /U.S. Government/\r\n classified.)\r\n $ color change\r\n (I) In a system being operated in periods-processing mode, the act\r\n of purging all information from one processing period and then\r\n changing over to the next processing period. (See: BLACK, RED.)\r\n $ Commercial COMSEC Evaluation Program (CCEP)\r\n (O) \"Relationship between NSA and industry in which NSA provides\r\n the COMSEC expertise (i.e., standards, algorithms, evaluations,\r\n and guidance) and industry provides design, development, and\r\n production capabilities to produce a type 1 or type 2 product.\"\r\n [C4009]\r\n $ commercially licensed evaluation facility (CLEF)\r\n (N) An organization that has official approval to evaluate the\r\n security of products and systems under the Common Criteria, ITSEC,\r\n or some other standard. (Compare: KLIF.)\r\n $ Committee on National Security Systems (CNSS)\r\n (O) /U.S. Government/ A Government, interagency, standing\r\n committee of the President's Critical Infrastructure Protection\r\n Board. The CNSS is chaired by the Secretary of Defense and\r\n provides a forum for the discussion of policy issues, sets\r\n national policy, and promulgates direction, operational\r\n procedures, and guidance for the security of national security\r\n systems. The Secretary of Defense and the Director of Central\r\n Intelligence are responsible for developing and overseeing the\r\n implementation of Government-wide policies, principles, standards,\r\n and guidelines for the security of systems that handle national\r\n security information.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 82 of 436\n\n$ Common Criteria for Information Technology Security\r\n (N) A standard for evaluating information technology (IT) products\r\n and systems. It states requirements for security functions and for\r\n assurance measures. [CCIB] (See: CLEF, EAL, packages, protection\r\n profile, security target, TOE. Compare: CMM.)\r\n Tutorial: Canada, France, Germany, the Netherlands, the United\r\n Kingdom, and the United States (NIST and NSA) began developing\r\n this standard in 1993, based on the European ITSEC, the Canadian\r\n Trusted Computer Product Evaluation Criteria (CTCPEC), and the\r\n U.S. \"Federal Criteria for Information Technology Security\" and\r\n its precursor, the TCSEC. Work was done in cooperation with\r\n ISO/IEC Joint Technical Committee 1 (Information Technology),\r\nShirey Informational [Page 69]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Subcommittee 27 (Security Techniques), Working Group 3 (Security\r\n Criteria). Version 2.0 of the Criteria has been issued as ISO's\r\n International Standard 15408. The U.S. Government intends this\r\n standard to supersede both the TCSEC and FIPS PUB 140. (See:\r\n NIAP.)\r\n The standard addresses data confidentiality, data integrity, and\r\n availability and may apply to other aspects of security. It\r\n focuses on threats to information arising from human activities,\r\n malicious or otherwise, but may apply to non-human threats. It\r\n applies to security measures implemented in hardware, firmware, or\r\n software. It does not apply to (a) administrative security not\r\n related directly to technical security, (b) technical physical\r\n aspects of security such as electromagnetic emanation control, (c)\r\n evaluation methodology or administrative and legal framework under\r\n which the criteria may be applied, (d) procedures for use of\r\n evaluation results, or (e) assessment of inherent qualities of\r\n cryptographic algorithms.\r\n Part 1, Introduction and General Model, defines general concepts\r\n and principles of IT security evaluation; presents a general model\r\n of evaluation; and defines constructs for expressing IT security\r\n objectives, for selecting and defining IT security requirements,\r\n and for writing high-level specifications for products and\r\n systems.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 83 of 436\n\nPart 2, Security Functional Requirements, contains a catalog of\r\n well-defined and well-understood functional requirement statements\r\n that are intended to be used as a standard way of expressing the\r\n security requirements for IT products and systems.\r\n Part 3, Security Assurance Requirements, contains a catalog of\r\n assurance components for use as a standard way of expressing such\r\n requirements for IT products and systems, and defines evaluation\r\n criteria for protection profiles and security targets.\r\n $ Common IP Security Option (CIPSO)\r\n (I) See: secondary definition under \"IPSO\".\r\n $ common name\r\n (N) A character string that (a) may be a part of the X.500 DN of a\r\n Directory object (\"commonName\" attribute), (b) is a (possibly\r\n ambiguous) name by which the object is commonly known in some\r\n limited scope (such as an organization), and (c) conforms to the\r\n naming conventions of the country or culture with which it is\r\n associated. [X520] (See: \"subject\" and \"issuer\" under \"X.509\r\n public-key certificate\".)\r\nShirey Informational [Page 70]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Examples: \"Dr. Albert Einstein\", \"The United Nations\", and \"12-th\r\n Floor Laser Printer\".\r\n $ communications cover\r\n (N) \"Concealing or altering of characteristic communications\r\n patterns to hide information that could be of value to an\r\n adversary.\" [C4009] (See: operations security, traffic-flow\r\n confidentiality, TRANSEC.)\r\n $ communication security (COMSEC)\r\n (I) Measures that implement and assure security services in a\r\n communication system, particularly those that provide data\r\n confidentiality and data integrity and that authenticate\r\n communicating entities.\r\n Usage: COMSEC is usually understood to include (a) cryptography\r\n and its related algorithms and key management methods and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 84 of 436\n\nprocesses, devices that implement those algorithms and processes,\r\n and the lifecycle management of the devices and keying material.\r\n Also, COMSEC is sometimes more broadly understood as further\r\n including (b) traffic-flow confidentiality, (c) TRANSEC, and (d)\r\n steganography [Kahn]. (See: cryptology, signal security.)\r\n $ community of interest (COI)\r\n 1. (I) A set of entities that operate under a common security\r\n policy. (Compare: domain.)\r\n 2. (I) A set of entities that exchange information collaboratively\r\n for some purpose.\r\n $ community risk\r\n (N) Probability that a particular vulnerability will be exploited\r\n within an interacting population and adversely affect some members\r\n of that population. [C4009] (See: Morris worm, risk.)\r\n $ community string\r\n (I) A community name in the form of an octet string that serves as\r\n a cleartext password in SNMP version 1 (RFC 1157) and version 2\r\n (RFC 1901). (See: password, Simple Network Management Protocol.)\r\n Tutorial: The SNMPv1 and SNMPv2 protocols have been declared\r\n \"historic\" and have been replaced by the more secure SNMPv3\r\n standard (RFCs 3410-3418), which does not use cleartext passwords.\r\nShirey Informational [Page 71]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ compartment\r\n 1. (I) A grouping of sensitive information items that require\r\n special access controls beyond those normally provided for the\r\n basic classification level of the information. (See: compartmented\r\n security mode. Compare: category, classification.)\r\n Usage: The term is usually understood to include the special\r\n handling procedures to be used for the information.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 85 of 436\n\n2. (I) Synonym for \"category\".\r\n Deprecated Usage: This Glossary defines \"category\" with a slightly\r\n narrower meaning than \"compartment\". That is, a security label is\r\n assigned to a category because the data owner needs to handle the\r\n data as a compartment. However, a compartment could receive\r\n special protection in a system without being assigned a category\r\n label.\r\n $ compartmented security mode\r\n (N) A mode of system operation wherein all users having access to\r\n the system have the necessary security clearance for the single,\r\n hierarchical classification level of all data handled by the\r\n system, but some users do not have the clearance for a non-\r\n hierarchical category of some data handled by the system. (See:\r\n category, /system operation/ under \"mode\", protection level,\r\n security clearance.)\r\n Usage: Usually abbreviated as \"compartmented mode\". This term was\r\n defined in U.S. Government policy on system accreditation. In this\r\n mode, a system may handle (a) a single hierarchical classification\r\n level and (b) multiple non-hierarchical categories within that\r\n level.\r\n $ Compartments field\r\n (I) A 16-bit field (the \"C field\") that specifies compartment\r\n values in the security option (option type 130) of version 4 IP's\r\n datagram header format. The valid field values are assigned by the\r\n U.S. Government, as specified in RFC 791.\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use the abbreviation \"C\r\n field\"; the abbreviation is potentially ambiguous. Instead, use\r\n \"Compartments field\".\r\n $ component\r\n See: system component.\r\nShirey Informational [Page 72]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 86 of 436\n\n$ compression\r\n (I) A process that encodes information in a way that minimizes the\r\n number of resulting code symbols and thus reduces storage space or\r\n transmission time.\r\n Tutorial: A data compression algorithm may be \"lossless\", i.e.,\r\n retain all information that was encoded in the data, so that\r\n decompression can recover all the information; or an algorithm may\r\n be \"lossy\". Text usually needs to be compressed losslessly, but\r\n images are often compressed with lossy schemes.\r\n Not all schemes that encode information losslessly for machine\r\n processing are efficient in terms of minimizing the number of\r\n output bits. For example, ASCII encoding is lossless, but ASCII\r\n data can often be losslessly reencoded in fewer bits with other\r\n schemes. These more efficient schemes take advantage of some sort\r\n of inherent imbalance, redundancy, or repetition in the data, such\r\n as by replacing a character string in which all characters are the\r\n same by a shorter string consisting of only the single character\r\n and a character count.\r\n Lossless compression schemes cannot effectively reduce the number\r\n of bits in cipher text produced by a strong encryption algorithm,\r\n because the cipher text is essentially a pseudorandom bit string\r\n that does not contain patterns susceptible to reencoding.\r\n Therefore, protocols that offer both encryption and compression\r\n services (e.g., SSL) need to perform the compression operation\r\n before the encryption operation.\r\n $ compromise\r\n See: data compromise, security compromise.\r\n $ compromise recovery\r\n (I) The process of regaining a secure state for a system after\r\n detecting that the system has experienced a security compromise.\r\n $ compromised key list (CKL)\r\n (N) /MISSI/ A list that identifies keys for which unauthorized\r\n disclosure or alteration may have occurred. (See: compromise.)\r\n Tutorial: A CKL is issued by a CA, like a CRL is issued. But a CKL\r\n lists only KMIDs, not subjects that hold the keys, and not\r\n certificates in which the keys are bound.\r\n $ COMPUSEC\r\n (I) See: computer security.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 87 of 436\n\nShirey Informational [Page 73]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ computer emergency response team (CERT)\r\n (I) An organization that studies computer and network INFOSEC in\r\n order to provide incident response services to victims of attacks,\r\n publish alerts concerning vulnerabilities and threats, and offer\r\n other information to help improve computer and network security.\r\n (See: CSIRT, security incident.)\r\n Examples: CERT Coordination Center at Carnegie Mellon University\r\n (sometimes called \"the\" CERT); CIAC.\r\n $ Computer Incident Advisory Capability (CIAC)\r\n (O) The centralized CSIRT of the U.S. Department of Energy; a\r\n member of FIRST.\r\n $ computer network\r\n (I) A collection of host computers together with the subnetwork or\r\n internetwork through which they can exchange data.\r\n Usage: This definition is intended to cover systems of all sizes\r\n and types, ranging from the complex Internet to a simple system\r\n composed of a personal computer dialing in as a remote terminal of\r\n another computer.\r\n $ computer platform\r\n (I) A combination of computer hardware and an operating system\r\n (which may consist of software, firmware, or both) for that\r\n hardware. (Compare: computer system.)\r\n $ computer security (COMPUSEC)\r\n 1. (I) Measures to implement and assure security services in a\r\n computer system, particularly those that assure access control\r\n service.\r\n Usage: Usually refers to internal controls (functions, features,\r\n and technical characteristics) that are implemented in software\r\n (especially in operating systems); sometimes refers to internal\r\n controls implemented in hardware; rarely used to refer to external\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 88 of 436\n\ncontrols.\r\n 2. (O) \"The protection afforded to an automated information system\r\n in order to attain the applicable objectives of preserving the\r\n integrity, availability and confidentiality of information system\r\n resources (includes hardware, software, firmware,\r\n information/data, and telecommunications).\" [SP12]\r\nShirey Informational [Page 74]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ computer security incident response team (CSIRT)\r\n (I) An organization \"that coordinates and supports the response to\r\n security incidents that involve sites within a defined\r\n constituency.\" [R2350] (See: CERT, FIRST, security incident.)\r\n Tutorial: To be considered a CSIRT, an organization must do as\r\n follows: (a) Provide a (secure) channel for receiving reports\r\n about suspected security incidents. (b) Provide assistance to\r\n members of its constituency in handling the incidents. (c)\r\n Disseminate incident-related information to its constituency and\r\n other involved parties.\r\n $ computer security object\r\n (I) The definition or representation of a resource, tool, or\r\n mechanism used to maintain a condition of security in computerized\r\n environments. Includes many items referred to in standards that\r\n are either selected or defined by separate user communities.\r\n [CSOR] (See: object identifier, Computer Security Objects\r\n Register.)\r\n $ Computer Security Objects Register (CSOR)\r\n (N) A service operated by NIST is establishing a catalog for\r\n computer security objects to provide stable object definitions\r\n identified by unique names. The use of this register will enable\r\n the unambiguous specification of security parameters and\r\n algorithms to be used in secure data exchanges. (See: object\r\n identifier.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 89 of 436\n\nTutorial: The CSOR follows registration guidelines established by\r\n the international standards community and ANSI. Those guidelines\r\n establish minimum responsibilities for registration authorities\r\n and assign the top branches of an international registration\r\n hierarchy. Under that international registration hierarchy, the\r\n CSOR is responsible for the allocation of unique identifiers under\r\n the branch: {joint-iso-ccitt(2) country(16) us(840)\r\n organization(1) gov(101) csor(3)}.\r\n $ computer system\r\n (I) Synonym for \"information system\", or a component thereof.\r\n (Compare: computer platform.)\r\n $ Computers At Risk\r\n (O) The 1991 report [NRC91] of the System Security Study\r\n Committee, sponsored by the U.S. National Academy of Sciences and\r\n supported by the Defense Advanced Research Projects Agency of the\r\n U.S. DoD. It made many recommendations for industry and\r\n governments to improve computer security and trustworthiness. Some\r\n of the most important recommendations (e.g., establishing an\r\nShirey Informational [Page 75]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Information Security Foundation chartered by the U.S. Government)\r\n have not been implemented at all, and others (e.g., codifying\r\n Generally Accepted System Security Principles similar to\r\n accounting principles) have been implemented but not widely\r\n adopted [SP14, SP27].\r\n $ COMSEC\r\n (I) See: communication security.\r\n $ COMSEC account\r\n (O) /U.S. Government/ \"Administrative entity, identified by an\r\n account number, used to maintain accountability, custody, and\r\n control of COMSEC material.\" [C4009] (See: COMSEC custodian.)\r\n $ COMSEC accounting\r\n (O) /U.S. Government/ The process of creating, collecting, and\r\n maintaining data records that describe the status and custody of\r\n designated items of COMSEC material. (See: accounting legend\r\n code.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 90 of 436\n\nTutorial: Almost any secure information system needs to record a\r\n security audit trail, but a system that manages COMSEC material\r\n needs to record additional data about the status and custody of\r\n COMSEC items.\r\n - COMSEC tracking: The process of automatically collecting,\r\n recording, and managing information that describes the status\r\n of designated items of COMSEC material at all times during each\r\n product's lifecycle.\r\n - COMSEC controlling: The process of supplementing tracking data\r\n with custody data, which consists of explicit acknowledgements\r\n of system entities that they (a) have received specific COMSEC\r\n items and (b) are responsible for preventing exposure of those\r\n items.\r\n For example, a key management system that serves a large customer\r\n base needs to record tracking data for the same reasons that a\r\n national parcel delivery system does, i.e., to answer the question\r\n \"Where is that thing now?\". If keys are encrypted immediately upon\r\n generation and handled only in BLACK form between the point of\r\n generation and the point of use, then tracking may be all that is\r\n needed. However, in cases where keys are handled at least partly\r\n in RED form and are potentially subject to exposure, then tracking\r\n needs to be supplemented by controlling.\r\n Data that is used purely for tracking need be retained only\r\n temporarily, until an item's status changes. Data that is used for\r\n controlling is retained indefinitely to ensure accountability and\r\n support compromise recovery.\r\nShirey Informational [Page 76]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ COMSEC boundary\r\n (N) \"Definable perimeter encompassing all hardware, firmware, and\r\n software components performing critical COMSEC functions, such as\r\n key generation and key handling and storage.\" [C4009] (Compare:\r\n cryptographic boundary.)\r\n $ COMSEC custodian\r\n (O) /U.S. Government/ \"Individual designated by proper authority\r\n to be responsible for the receipt, transfer, accounting,\r\n safeguarding, and destruction of COMSEC material assigned to a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 91 of 436\n\nCOMSEC account.\" [C4009]\r\n $ COMSEC material\r\n (N) /U.S. Government/ Items designed to secure or authenticate\r\n communications or information in general; these items include (but\r\n are not limited to) keys; equipment, devices, documents, firmware,\r\n and software that embodies or describes cryptographic logic; and\r\n other items that perform COMSEC functions. [C4009] (Compare:\r\n keying material.)\r\n $ COMSEC Material Control System (CMCS)\r\n (O) /U.S. Government/ \"Logistics and accounting system through\r\n which COMSEC material marked 'CRYPTO' is distributed, controlled,\r\n and safeguarded.\" [C4009] (See: COMSEC account, COMSEC custodian.)\r\n $ confidentiality\r\n See: data confidentiality.\r\n $ concealment system\r\n (O) \"A method of achieving confidentiality in which sensitive\r\n information is hidden by embedding it in irrelevant data.\" [NCS04]\r\n (Compare: steganography.)\r\n $ configuration control\r\n (I) The process of regulating changes to hardware, firmware,\r\n software, and documentation throughout the development and\r\n operational life of a system. (See: administrative security,\r\n harden, trusted distribution.)\r\n Tutorial: Configuration control helps protect against unauthorized\r\n or malicious alteration of a system and thus provides assurance of\r\n system integrity. (See: malicious logic.)\r\n $ confinement property\r\n (N) /formal model/ Property of a system whereby a subject has\r\n write access to an object only if the classification of the object\r\n dominates the clearance of the subject. (See: *-property, Bell-\r\n LaPadula model.)\r\nShirey Informational [Page 77]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ constraint\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 92 of 436\n\n(I) /access control/ A limitation on the function of an identity,\r\n role, or privilege. (See: rule-based access control.)\r\n Tutorial: In effect, a constraint is a form of security policy and\r\n may be either static or dynamic:\r\n - \"Static constraint\": A constraint that must be satisfied at the\r\n time the policy is defined, and then continues to be satisfied\r\n until the constraint is removed.\r\n - \"Dynamic constraint\": A constraint that may be defined to apply\r\n at various times that the identity, role, or other object of\r\n the constraint is active in the system.\r\n $ content filter\r\n (I) /World Wide Web/ Application software used to prevent access\r\n to certain Web servers, such as by parents who do not want their\r\n children to access pornography. (See: filter, guard.)\r\n Tutorial: The filter is usually browser-based, but could be part\r\n of an intermediate cache server. The two basic content filtering\r\n techniques are (a) to block a specified list of URLs and (b) to\r\n block material that contains specified words and phrases.\r\n $ contingency plan\r\n (I) A plan for emergency response, backup operations, and post-\r\n disaster recovery in a system as part of a security program to\r\n ensure availability of critical system resources and facilitate\r\n continuity of operations in a crisis. [NCS04] (See: availability.)\r\n $ control zone\r\n (O) \"The space, expressed in feet of radius, surrounding equipment\r\n processing sensitive information, that is under sufficient\r\n physical and technical control to preclude an unauthorized entry\r\n or compromise.\" [NCSSG] (Compare: inspectable space, TEMPEST\r\n zone.)\r\n $ controlled access protection\r\n (O) /TCSEC/ The level of evaluation criteria for a C2 computer\r\n system.\r\n Tutorial: The major features of the C2 level are individual\r\n accountability, audit, access control, and object reuse.\r\n $ controlled cryptographic item (CCI)\r\n (O) /U.S. Government/ \"Secure telecommunications or information\r\n handling equipment, or associated cryptographic component, that is\r\n unclassified but governed by a special set of control\r\n requirements.\" [C4009] (Compare: EUCI.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 93 of 436\n\nShirey Informational [Page 78]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: This category of equipment was established in 1985 to\r\n promote broad use of secure equipment for protecting both\r\n classified and unclassified information in the national interest.\r\n CCI equipment uses a classified cryptographic logic, but the\r\n hardware or firmware embodiment of that logic is unclassified.\r\n Drawings, software implementations, and other descriptions of that\r\n logic remain classified. [N4001]\r\n $ controlled interface\r\n (I) A mechanism that facilitates the adjudication of the different\r\n security policies of interconnected systems. (See: domain, guard.)\r\n $ controlled security mode\r\n (D) /U.S. DoD/ A mode of system operation wherein (a) two or more\r\n security levels of information are allowed to be handled\r\n concurrently within the same system when some users having access\r\n to the system have neither a security clearance nor need-to-know\r\n for some of the data handled by the system, but (b) separation of\r\n the users and the classified material on the basis, respectively,\r\n of clearance and classification level are not dependent only on\r\n operating system control (like they are in multilevel security\r\n mode). (See: /system operation/ under \"mode\", protection level.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term. It was defined in\r\n a U.S. Government policy regarding system accreditation and was\r\n subsumed by \"partitioned security mode\" in a later policy. Both\r\n terms were dropped in still later policies.\r\n Tutorial: Controlled mode was intended to encourage ingenuity in\r\n meeting data confidentiality requirements in ways less restrictive\r\n than \"dedicated security mode\" and \"system-high security mode\",\r\n but at a level of risk lower than that generally associated with\r\n true \"multilevel security mode\". This was intended to be\r\n accomplished by implementation of explicit augmenting measures to\r\n reduce or remove a substantial measure of system software\r\n vulnerability together with specific limitation of the security\r\n clearance levels of users having concurrent access to the system.\r\n $ controlling authority\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 94 of 436\n\n(O) /U.S. Government/ \"Official responsible for directing the\r\n operation of a cryptonet and for managing the operational use and\r\n control of keying material assigned to the cryptonet.\" [C4009,\r\n N4006]\r\n $ cookie\r\n 1. (I) /HTTP/ Data exchanged between an HTTP server and a browser\r\n (a client of the server) to store state information on the client\r\n side and retrieve it later for server use.\r\nShirey Informational [Page 79]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: An HTTP server, when sending data to a client, may send\r\n along a cookie, which the client retains after the HTTP connection\r\n closes. A server can use this mechanism to maintain persistent\r\n client-side state information for HTTP-based applications,\r\n retrieving the state information in later connections. A cookie\r\n may include a description of the range of URLs for which the state\r\n is valid. Future requests made by the client in that range will\r\n also send the current value of the cookie to the server. Cookies\r\n can be used to generate profiles of web usage habits, and thus may\r\n infringe on personal privacy.\r\n 2. (I) /IPsec/ Data objects exchanged by ISAKMP to prevent certain\r\n denial-of-service attacks during the establishment of a security\r\n association.\r\n 3. (D) /access control/ Synonym for \"capability token\" or\r\n \"ticket\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 3; that would duplicate the meaning of better-\r\n established terms and mix concepts in a potentially misleading\r\n way.\r\n $ Coordinated Universal Time (UTC)\r\n (N) UTC is derived from International Atomic Time (TAI) by adding\r\n a number of leap seconds. The International Bureau of Weights and\r\n Measures computes TAI once each month by averaging data from many\r\n laboratories. (See: GeneralizedTime, UTCTime.)\r\n $ correction\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 95 of 436\n\n(I) /security/ A system change made to eliminate or reduce the\r\n risk of reoccurrence of a security violation or threat\r\n consequence. (See: secondary definition under \"security\".)\r\n $ correctness\r\n (I) \"The property of a system that is guaranteed as the result of\r\n formal verification activities.\" [Huff] (See: correctness proof,\r\n verification.)\r\n $ correctness integrity\r\n (I) The property that the information represented by data is\r\n accurate and consistent. (Compare: data integrity, source\r\n integrity.)\r\n Tutorial: IDOCs SHOULD NOT use this term without providing a\r\n definition; the term is neither well-known nor precisely defined.\r\n Data integrity refers to the constancy of data values, and source\r\n integrity refers to confidence in data values. However,\r\nShirey Informational [Page 80]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n correctness integrity refers to confidence in the underlying\r\n information that data values represent, and this property is\r\n closely related to issues of accountability and error handling.\r\n $ correctness proof\r\n (I) A mathematical proof of consistency between a specification\r\n for system security and the implementation of that specification.\r\n (See: correctness, formal specification.)\r\n $ corruption\r\n (I) A type of threat action that undesirably alters system\r\n operation by adversely modifying system functions or data. (See:\r\n disruption.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Tampering\": /corruption/ Deliberately altering a system's\r\n logic, data, or control information to interrupt or prevent\r\n correct operation of system functions. (See: misuse, main entry\r\n for \"tampering\".)\r\n - \"Malicious logic\": /corruption/ Any hardware, firmware, or\r\n software (e.g., a computer virus) intentionally introduced into\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 96 of 436\n\na system to modify system functions or data. (See:\r\n incapacitation, main entry for \"malicious logic\", masquerade,\r\n misuse.)\r\n - \"Human error\": /corruption/ Human action or inaction that\r\n unintentionally results in the alteration of system functions\r\n or data.\r\n - \"Hardware or software error\": /corruption/ Error that results\r\n in the alteration of system functions or data.\r\n - \"Natural disaster\": /corruption/ Any \"act of God\" (e.g., power\r\n surge caused by lightning) that alters system functions or\r\n data. [FP031 Section 2]\r\n $ counter\r\n 1. (N) /noun/ See: counter mode.\r\n 2. (I) /verb/ See: countermeasure.\r\n $ counter-countermeasure\r\n (I) An action, device, procedure, or technique used by an attacker\r\n to offset a defensive countermeasure.\r\n Tutorial: For every countermeasure devised to protect computers\r\n and networks, some cracker probably will be able to devise a\r\n counter-countermeasure. Thus, systems must use \"defense in depth\".\r\nShirey Informational [Page 81]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ counter mode (CTR)\r\n (N) A block cipher mode that enhances ECB mode by ensuring that\r\n each encrypted block is different from every other block encrypted\r\n under the same key. [SP38A] (See: block cipher.)\r\n Tutorial: This mode operates by first encrypting a generated\r\n sequence of blocks, called \"counters\", that are separate from the\r\n input sequence of plaintext blocks which the mode is intended to\r\n protect. The resulting sequence of encrypted counters is\r\n exclusive-ORed with the sequence of plaintext blocks to produce\r\n the final ciphertext output blocks. The sequence of counters must\r\n have the property that each counter is different from every other\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 97 of 436\n\ncounter for all of the plain text that is encrypted under the same\r\n key.\r\n $ Counter with Cipher Block Chaining-Message Authentication Code\r\n (CCM)\r\n (N) A block cipher mode [SP38C] that provides both data\r\n confidentiality and data origin authentication, by combining the\r\n techniques of CTR and a CBC-based message authentication code.\r\n (See: block cipher.)\r\n $ countermeasure\r\n (I) An action, device, procedure, or technique that meets or\r\n opposes (i.e., counters) a threat, a vulnerability, or an attack\r\n by eliminating or preventing it, by minimizing the harm it can\r\n cause, or by discovering and reporting it so that corrective\r\n action can be taken.\r\n Tutorial: In an Internet protocol, a countermeasure may take the\r\n form of a protocol feature, a component function, or a usage\r\n constraint.\r\n $ country code\r\n (I) An identifier that is defined for a nation by ISO. [I3166]\r\n Tutorial: For each nation, ISO Standard 3166 defines a unique two-\r\n character alphabetic code, a unique three-character alphabetic\r\n code, and a three-digit code. Among many uses of these codes, the\r\n two-character codes are used as top-level domain names.\r\n $ Courtney's laws\r\n (N) Principles for managing system security that were stated by\r\n Robert H. Courtney, Jr.\r\nShirey Informational [Page 82]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Bill Murray codified Courtney's laws as follows: [Murr]\r\n - Courtney's first law: You cannot say anything interesting\r\n (i.e., significant) about the security of a system except in\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 98 of 436\n\nthe context of a particular application and environment.\r\n - Courtney's second law: Never spend more money eliminating a\r\n security exposure than tolerating it will cost you. (See:\r\n acceptable risk, risk analysis.)\r\n -- First corollary: Perfect security has infinite cost.\r\n -- Second corollary: There is no such thing as zero risk.\r\n - Courtney's third law: There are no technical solutions to\r\n management problems, but there are management solutions to\r\n technical problems.\r\n $ covert action\r\n (I) An operation that is planned and executed in a way that\r\n conceals the identity of the operator.\r\n $ covert channel\r\n 1. (I) An unintended or unauthorized intra-system channel that\r\n enables two cooperating entities to transfer information in a way\r\n that violates the system's security policy but does not exceed the\r\n entities' access authorizations. (See: covert storage channel,\r\n covert timing channel, out-of-band, tunnel.)\r\n 2. (O) \"A communications channel that allows two cooperating\r\n processes to transfer information in a manner that violates the\r\n system's security policy.\" [NCS04]\r\n Tutorial: The cooperating entities can be either two insiders or\r\n an insider and an outsider. Of course, an outsider has no access\r\n authorization at all. A covert channel is a system feature that\r\n the system architects neither designed nor intended for\r\n information transfer.\r\n $ covert storage channel\r\n (I) A system feature that enables one system entity to signal\r\n information to another entity by directly or indirectly writing a\r\n storage location that is later directly or indirectly read by the\r\n second entity. (See: covert channel.)\r\n $ covert timing channel\r\n (I) A system feature that enables one system entity to signal\r\n information to another by modulating its own use of a system\r\n resource in such a way as to affect system response time observed\r\n by the second entity. (See: covert channel.)\r\n $ CPS\r\n (I) See: certification practice statement.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 99 of 436\n\nShirey Informational [Page 83]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ cracker\r\n (I) Someone who tries to break the security of, and gain\r\n unauthorized access to, someone else's system, often with\r\n malicious intent. (See: adversary, intruder, packet monkey, script\r\n kiddy. Compare: hacker.)\r\n Usage: Was sometimes spelled \"kracker\". [NCSSG]\r\n $ CRAM\r\n (I) See: Challenge-Response Authentication Mechanism.\r\n $ CRC\r\n (I) See: cyclic redundancy check.\r\n $ credential\r\n 1. (I) /authentication/ \"identifier credential\": A data object\r\n that is a portable representation of the association between an\r\n identifier and a unit of authentication information, and that can\r\n be presented for use in verifying an identity claimed by an entity\r\n that attempts to access a system. Example: X.509 public-key\r\n certificate. (See: anonymous credential.)\r\n 2. (I) /access control/ \"authorization credential\": A data object\r\n that is a portable representation of the association between an\r\n identifier and one or more access authorizations, and that can be\r\n presented for use in verifying those authorizations for an entity\r\n that attempts such access. Example: X.509 attribute certificate.\r\n (See: capability token, ticket.)\r\n 3. (D) /OSIRM/ \"Data that is transferred to establish the claimed\r\n identity of an entity.\" [I7498-2]\r\n Deprecated Definition: IDOCs SHOULD NOT use the term with\r\n definition 3. As explained in the tutorial below, an\r\n authentication process can involve the transfer of multiple data\r\n objects, and not all of those are credentials.\r\n 4. (D) /U.S. Government/ \"An object that is verified when\r\n presented to the verifier in an authentication transaction.\"\r\n [M0404]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 100 of 436\n\nDeprecated Definition: IDOCs SHOULD NOT use the term with\r\n definition 4; it mixes concepts in a potentially misleading way.\r\n For example, in an authentication process, it is the identity that\r\n is \"verified\", not the credential; the credential is \"validated\".\r\n (See: validate vs. verify.)\r\nShirey Informational [Page 84]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: In general English, \"credentials\" are evidence or\r\n testimonials that (a) support a claim of identity or authorization\r\n and (b) usually are intended to be used more than once (i.e., a\r\n credential's life is long compared to the time needed for one\r\n use). Some examples are a policeman's badge, an automobile\r\n driver's license, and a national passport. An authentication or\r\n access control process that uses a badge, license, or passport is\r\n outwardly simple: the holder just shows the thing.\r\n The problem with adopting this term in Internet security is that\r\n an automated process for authentication or access control usually\r\n requires multiple steps using multiple data objects, and it might\r\n not be immediately obvious which of those objects should get the\r\n name \"credential\".\r\n For example, if the verification step in a user authentication\r\n process employs public-key technology, then the process involves\r\n at least three data items: (a) the user's private key, (b) a\r\n signed value -- signed with that private key and passed to the\r\n system, perhaps in response to a challenge from the system -- and\r\n (c) the user's public-key certificate, which is validated by the\r\n system and provides the public key needed to verify the signature.\r\n - Private key: The private key is *not* a credential, because it\r\n is never transferred or presented. Instead, the private key is\r\n \"authentication information\", which is associated with the\r\n user's identifier for a specified period of time and can be\r\n used in multiple authentications during that time.\r\n - Signed value: The signed value is *not* a credential; the\r\n signed value is only ephemeral, not long lasting. The OSIRM\r\n definition could be interpreted to call the signed value a\r\n credential, but that would conflict with general English.\r\n - Certificate: The user's certificate *is* a credential. It can\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 101 of 436\n\nbe \"transferred\" or \"presented\" to any person or process that\r\n needs it at any time. A public-key certificate may be used as\r\n an \"identity credential\", and an attribute certificate may be\r\n used as an \"authorization credential\".\r\n $ critical\r\n 1. (I) /system resource/ A condition of a system resource such\r\n that denial of access to, or lack of availability of, that\r\n resource would jeopardize a system user's ability to perform a\r\n primary function or would result in other serious consequences,\r\n such as human injury or loss of life. (See: availability,\r\n precedence. Compare: sensitive.)\r\n 2. (N) /extension/ An indication that an application is not\r\n permitted to ignore an extension. [X509]\r\nShirey Informational [Page 85]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Each extension of an X.509 certificate or CRL is flagged\r\n as either \"critical\" or \"non-critical\". In a certificate, if a\r\n computer program does not recognize an extension's type (i.e.,\r\n does not implement its semantics), then if the extension is\r\n critical, the program is required to treat the certificate as\r\n invalid; but if the extension is non-critical, the program is\r\n permitted to ignore the extension.\r\n In a CRL, if a program does not recognize a critical extension\r\n that is associated with a specific certificate, the program is\r\n required to assume that the listed certificate has been revoked\r\n and is no longer valid, and then take whatever action is required\r\n by local policy.\r\n When a program does not recognize a critical extension that is\r\n associated with the CRL as a whole, the program is required to\r\n assume that all listed certificates have been revoked and are no\r\n longer valid. However, since failing to process the extension may\r\n mean that the list has not been completed, the program cannot\r\n assume that other certificates are valid, and the program needs to\r\n take whatever action is therefore required by local policy.\r\n $ critical information infrastructure\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 102 of 436\n\n(I) Those systems that are so vital to a nation that their\r\n incapacity or destruction would have a debilitating effect on\r\n national security, the economy, or public health and safety.\r\n $ CRL\r\n (I) See: certificate revocation list.\r\n $ CRL distribution point\r\n (I) See: distribution point.\r\n $ CRL extension\r\n (I) See: extension.\r\n $ cross-certificate\r\n (I) A public-key certificate issued by a CA in one PKI to a CA in\r\n another PKI. (See: cross-certification.)\r\n $ cross-certification\r\n (I) The act or process by which a CA in one PKI issues a public-\r\n key certificate to a CA in another PKI. [X509] (See: bridge CA.)\r\n Tutorial: X.509 says that a CA (say, CA1) may issue a \"cross-\r\n certificate\" in which the subject is another CA (say, CA2). X.509\r\n calls CA2 the \"subject CA\" and calls CA1 an \"intermediate CA\", but\r\nShirey Informational [Page 86]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n this Glossary deprecates those terms. (See: intermediate CA,\r\n subject CA).\r\n Cross-certification of CA2 by CA1 appears similar to certification\r\n of a subordinate CA by a superior CA, but cross-certification\r\n involves a different concept. The \"subordinate CA\" concept applies\r\n when both CAs are in the same PKI, i.e., when either (a) CA1 and\r\n CA2 are under the same root or (b) CA1 is itself a root. The\r\n \"cross-certification\" concept applies in other cases:\r\n First, cross-certification applies when two CAs are in different\r\n PKIs, i.e., when CA1 and CA2 are under different roots, or perhaps\r\n are both roots themselves. Issuing the cross-certificate enables\r\n end entities certified under CA1 in PK1 to construct the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 103 of 436\n\ncertification paths needed to validate the certificates of end\r\n entities certified under CA2 in PKI2. Sometimes, a pair of cross-\r\n certificates is issued -- by CA1 to CA2, and by CA2 to CA1 -- so\r\n that an end entity in either PKI can validate certificates issued\r\n in the other PKI.\r\n Second, X.509 says that two CAs in some complex, multi-CA PKI can\r\n cross-certify one another to shorten the certification paths\r\n constructed by end entities. Whether or not a CA may perform this\r\n or any other form of cross-certification, and how such\r\n certificates may be used by end entities, should be addressed by\r\n the local certificate policy and CPS.\r\n $ cross-domain solution\r\n 1. (D) Synonym for \"guard\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"guard\"; this term unnecessarily (and verbosely) duplicates the\r\n meaning of the long-established \"guard\".\r\n 2. (O) /U.S. Government/ A process or subsystem that provides a\r\n capability (which could be either manual or automated) to access\r\n two or more differing security domains in a system, or to transfer\r\n information between such domains. (See: domain, guard.)\r\n $ cryptanalysis\r\n 1. (I) The mathematical science that deals with analysis of a\r\n cryptographic system to gain knowledge needed to break or\r\n circumvent the protection that the system is designed to provide.\r\n (See: cryptology, secondary definition under \"intrusion\".)\r\n 2. (O) \"The analysis of a cryptographic system and/or its inputs\r\n and outputs to derive confidential variables and/or sensitive data\r\n including cleartext.\" [I7498-2]\r\nShirey Informational [Page 87]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Definition 2 states the traditional goal of\r\n cryptanalysis, i.e., convert cipher text to plain text (which\r\n usually is clear text) without knowing the key; but that\r\n definition applies only to encryption systems. Today, the term is\r\n used with reference to all kinds of cryptographic algorithms and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 104 of 436\n\nkey management, and definition 1 reflects that. In all cases,\r\n however, a cryptanalyst tries to uncover or reproduce someone\r\n else's sensitive data, such as clear text, a key, or an algorithm.\r\n The basic cryptanalytic attacks on encryption systems are\r\n ciphertext-only, known-plaintext, chosen-plaintext, and chosen-\r\n ciphertext; and these generalize to the other kinds of\r\n cryptography.\r\n $ crypto, CRYPTO\r\n 1. (N) A prefix (\"crypto-\") that means \"cryptographic\".\r\n Usage: IDOCs MAY use this prefix when it is part of a term listed\r\n in this Glossary. Otherwise, IDOCs SHOULD NOT use this prefix;\r\n instead, use the unabbreviated adjective, \"cryptographic\".\r\n 2. (D) In lower case, \"crypto\" is an abbreviation for the\r\n adjective \"cryptographic\", or for the nouns \"cryptography\" or\r\n \"cryptographic component\".\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use this abbreviation\r\n because it could easily be misunderstood in some technical sense.\r\n 3. (O) /U.S. Government/ In upper case, \"CRYPTO\" is a marking or\r\n designator that identifies \"COMSEC keying material used to secure\r\n or authenticate telecommunications carrying classified or\r\n sensitive U.S. Government or U.S. Government-derived information.\"\r\n [C4009] (See: security label, security marking.)\r\n $ cryptographic\r\n (I) An adjective that refers to cryptography.\r\n $ cryptographic algorithm\r\n (I) An algorithm that uses the science of cryptography, including\r\n (a) encryption algorithms, (b) cryptographic hash algorithms, (c)\r\n digital signature algorithms, and (d) key-agreement algorithms.\r\n $ cryptographic application programming interface (CAPI)\r\n (I) The source code formats and procedures through which an\r\n application program accesses cryptographic services, which are\r\n defined abstractly compared to their actual implementation.\r\n Example, see: PKCS #11, [R2628].\r\nShirey Informational [Page 88]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 105 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ cryptographic association\r\n (I) A security association that involves the use of cryptography\r\n to provide security services for data exchanged by the associated\r\n entities. (See: ISAKMP.)\r\n $ cryptographic boundary\r\n (I) See: secondary definition under \"cryptographic module\".\r\n $ cryptographic card\r\n (I) A cryptographic token in the form of a smart card or a PC\r\n card.\r\n $ cryptographic component\r\n (I) A generic term for any system component that involves\r\n cryptography. (See: cryptographic module.)\r\n $ cryptographic hash\r\n (I) See: secondary definition under \"hash function\".\r\n $ cryptographic ignition key (CIK)\r\n 1. (N) A physical (usually electronic) token used to store,\r\n transport, and protect cryptographic keys and activation data.\r\n (Compare: dongle, fill device.)\r\n Tutorial: A key-encrypting key could be divided (see: split key)\r\n between a CIK and a cryptographic module, so that it would be\r\n necessary to combine the two to regenerate the key, use it to\r\n decrypt other keys and data contained in the module, and thus\r\n activate the module.\r\n 2. (O) \"Device or electronic key used to unlock the secure mode of\r\n cryptographic equipment.\" [C4009] Usage: Abbreviated as \"crypto-\r\n ignition key\".\r\n $ cryptographic key\r\n (I) See: key. Usage: Usually shortened to just \"key\".\r\n $ Cryptographic Message Syntax (CMS)\r\n (I) An encapsulation syntax (RFC 3852) for digital signatures,\r\n hashes, and encryption of arbitrary messages.\r\n Tutorial: CMS derives from PKCS #7. CMS values are specified with\r\n ASN.1 and use BER encoding. The syntax permits multiple\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 106 of 436\n\nencapsulation with nesting, permits arbitrary attributes to be\r\n signed along with message content, and supports a variety of\r\n architectures for digital certificate-based key management.\r\nShirey Informational [Page 89]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ cryptographic module\r\n (I) A set of hardware, software, firmware, or some combination\r\n thereof that implements cryptographic logic or processes,\r\n including cryptographic algorithms, and is contained within the\r\n module's \"cryptographic boundary\", which is an explicitly defined\r\n contiguous perimeter that establishes the physical bounds of the\r\n module. [FP140]\r\n $ cryptographic system\r\n 1. (I) A set of cryptographic algorithms together with the key\r\n management processes that support use of the algorithms in some\r\n application context.\r\n Usage: IDOCs SHOULD use definition 1 because it covers a wider\r\n range of algorithms than definition 2.\r\n 2. (O) \"A collection of transformations from plain text into\r\n cipher text and vice versa [which would exclude digital signature,\r\n cryptographic hash, and key-agreement algorithms], the particular\r\n transformation(s) to be used being selected by keys. The\r\n transformations are normally defined by a mathematical algorithm.\"\r\n [X509]\r\n $ cryptographic token\r\n 1. (I) A portable, user-controlled, physical device (e.g., smart\r\n card or PCMCIA card) used to store cryptographic information and\r\n possibly also perform cryptographic functions. (See: cryptographic\r\n card, token.)\r\n Tutorial: A smart token might implement some set of cryptographic\r\n algorithms and might incorporate related key management functions,\r\n such as a random number generator. A smart cryptographic token may\r\n contain a cryptographic module or may not be explicitly designed\r\n that way.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 107 of 436\n\n$ cryptography\r\n 1. (I) The mathematical science that deals with transforming data\r\n to render its meaning unintelligible (i.e., to hide its semantic\r\n content), prevent its undetected alteration, or prevent its\r\n unauthorized use. If the transformation is reversible,\r\n cryptography also deals with restoring encrypted data to\r\n intelligible form. (See: cryptology, steganography.)\r\n 2. (O) \"The discipline which embodies principles, means, and\r\n methods for the transformation of data in order to hide its\r\n information content, prevent its undetected modification and/or\r\n prevent its unauthorized use.... Cryptography determines the\r\n methods used in encipherment and decipherment.\" [I7498-2]\r\nShirey Informational [Page 90]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Comprehensive coverage of applied cryptographic\r\n protocols and algorithms is provided by Schneier [Schn].\r\n Businesses and governments use cryptography to make data\r\n incomprehensible to outsiders; to make data incomprehensible to\r\n both outsiders and insiders, the data is sent to lawyers for a\r\n rewrite.\r\n $ Cryptoki\r\n (N) A CAPI defined in PKCS #11. Pronunciation: \"CRYPTO-key\".\r\n Derivation: Abbreviation of \"cryptographic token interface\".\r\n $ cryptology\r\n (I) The science of secret communication, which includes both\r\n cryptography and cryptanalysis.\r\n Tutorial: Sometimes the term is used more broadly to denote\r\n activity that includes both rendering signals secure (see: signal\r\n security) and extracting information from signals (see: signal\r\n intelligence) [Kahn].\r\n $ cryptonet\r\n (I) A network (i.e., a communicating set) of system entities that\r\n share a secret cryptographic key for a symmetric algorithm. (See:\r\n controlling authority.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 108 of 436\n\n(O) \"Stations holding a common key.\" [C4009]\r\n $ cryptoperiod\r\n (I) The time span during which a particular key value is\r\n authorized to be used in a cryptographic system. (See: key\r\n management.)\r\n Usage: This term is long-established in COMPUSEC usage. In the\r\n context of certificates and public keys, \"key lifetime\" and\r\n \"validity period\" are often used instead.\r\n Tutorial: A cryptoperiod is usually stated in terms of calendar or\r\n clock time, but sometimes is stated in terms of the maximum amount\r\n of data permitted to be processed by a cryptographic algorithm\r\n using the key. Specifying a cryptoperiod involves a tradeoff\r\n between the cost of rekeying and the risk of successful\r\n cryptoanalysis.\r\n $ cryptosystem\r\n (I) Contraction of \"cryptographic system\".\r\n $ cryptovariable\r\n (D) Synonym for \"key\".\r\nShirey Informational [Page 91]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Usage: In contemporary COMSEC usage, the term \"key\" has\r\n replaced the term \"cryptovariable\".\r\n $ CSIRT\r\n (I) See: computer security incident response team.\r\n $ CSOR\r\n (N) See: Computer Security Objects Register.\r\n $ CTAK\r\n (D) See: ciphertext auto-key.\r\n $ CTR\r\n (N) See: counter mode.\r\n $ cut-and-paste attack\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 109 of 436\n\n(I) An active attack on the data integrity of cipher text,\r\n effected by replacing sections of cipher text with other cipher\r\n text, such that the result appears to decrypt correctly but\r\n actually decrypts to plain text that is forged to the satisfaction\r\n of the attacker.\r\n $ cyclic redundancy check (CRC)\r\n (I) A type of checksum algorithm that is not a cryptographic hash\r\n but is used to implement data integrity service where accidental\r\n changes to data are expected. Sometimes called \"cyclic redundancy\r\n code\".\r\n $ DAC\r\n (N) See: Data Authentication Code, discretionary access control.\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because this abbreviation is ambiguous.\r\n $ daemon\r\n (I) A computer program that is not invoked explicitly but waits\r\n until a specified condition occurs, and then runs with no\r\n associated user (principal), usually for an administrative\r\n purpose. (See: zombie.)\r\n $ dangling threat\r\n (O) A threat to a system for which there is no corresponding\r\n vulnerability and, therefore, no implied risk.\r\n $ dangling vulnerability\r\n (O) A vulnerability of a system for which there is no\r\n corresponding threat and, therefore, no implied risk.\r\nShirey Informational [Page 92]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ DASS\r\n (I) See: Distributed Authentication Security Service.\r\n $ data\r\n (I) Information in a specific representation, usually as a\r\n sequence of symbols that have meaning.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 110 of 436\n\nUsage: Refers to both (a) representations that can be recognized,\r\n processed, or produced by a computer or other type of machine, and\r\n (b) representations that can be handled by a human.\r\n $ Data Authentication Algorithm, data authentication algorithm\r\n 1. (N) /capitalized/ The ANSI standard for a keyed hash function\r\n that is equivalent to DES cipher block chaining with IV = 0.\r\n [A9009]\r\n 2. (D) /not capitalized/ Synonym for some kind of \"checksum\".\r\n Deprecated Term: IDOCs SHOULD NOT use the uncapitalized form \"data\r\n authentication algorithm\" as a synonym for any kind of checksum,\r\n regardless of whether or not the checksum is based on a hash.\r\n Instead, use \"checksum\", \"Data Authentication Code\", \"error\r\n detection code\", \"hash\", \"keyed hash\", \"Message Authentication\r\n Code\", \"protected checksum\", or some other specific term,\r\n depending on what is meant.\r\n The uncapitalized term can be confused with the Data\r\n Authentication Code and also mixes concepts in a potentially\r\n misleading way. The word \"authentication\" is misleading because\r\n the checksum may be used to perform a data integrity function\r\n rather than a data origin authentication function.\r\n $ Data Authentication Code, data authentication code\r\n 1. (N) /capitalized/ A specific U.S. Government standard [FP113]\r\n for a checksum that is computed by the Data Authentication\r\n Algorithm. Usage: a.k.a. Message Authentication Code [A9009].)\r\n (See: DAC.)\r\n 2. (D) /not capitalized/ Synonym for some kind of \"checksum\".\r\n Deprecated Term: IDOCs SHOULD NOT use the uncapitalized form \"data\r\n authentication code\" as a synonym for any kind of checksum,\r\n regardless of whether or not the checksum is based on the Data\r\n Authentication Algorithm. The uncapitalized term can be confused\r\n with the Data Authentication Code and also mixes concepts in a\r\n potentially misleading way (see: authentication code).\r\nShirey Informational [Page 93]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 111 of 436\n\n$ data compromise\r\n 1. (I) A security incident in which information is exposed to\r\n potential unauthorized access, such that unauthorized disclosure,\r\n alteration, or use of the information might have occurred.\r\n (Compare: security compromise, security incident.)\r\n 2. (O) /U.S. DoD/ A \"compromise\" is a \"communication or physical\r\n transfer of information to an unauthorized recipient.\" [DoD5]\r\n 3. (O) /U.S. Government/ \"Type of [security] incident where\r\n information is disclosed to unauthorized individuals or a\r\n violation of the security policy of a system in which unauthorized\r\n intentional or unintentional disclosure, modification,\r\n destruction, or loss of an object may have occurred.\" [C4009]\r\n $ data confidentiality\r\n 1. (I) The property that data is not disclosed to system entities\r\n unless they have been authorized to know the data. (See: Bell-\r\n LaPadula model, classification, data confidentiality service,\r\n secret. Compare: privacy.)\r\n 2. (D) \"The property that information is not made available or\r\n disclosed to unauthorized individuals, entities, or processes\r\n [i.e., to any unauthorized system entity].\" [I7498-2].\r\n Deprecated Definition: The phrase \"made available\" might be\r\n interpreted to mean that the data could be altered, and that would\r\n confuse this term with the concept of \"data integrity\".\r\n $ data confidentiality service\r\n (I) A security service that protects data against unauthorized\r\n disclosure. (See: access control, data confidentiality, datagram\r\n confidentiality service, flow control, inference control.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n \"privacy\", which is a different concept.\r\n $ Data Encryption Algorithm (DEA)\r\n (N) A symmetric block cipher, defined in the U.S. Government's\r\n DES. DEA uses a 64-bit key, of which 56 bits are independently\r\n chosen and 8 are parity bits, and maps a 64-bit block into another\r\n 64-bit block. [FP046] (See: AES, symmetric cryptography.)\r\n Usage: This algorithm is usually referred to as \"DES\". The\r\n algorithm has also been adopted in standards outside the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 112 of 436\n\nGovernment (e.g., [A3092]).\r\nShirey Informational [Page 94]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ data encryption key (DEK)\r\n (I) A cryptographic key that is used to encipher application data.\r\n (Compare: key-encrypting key.)\r\n $ Data Encryption Standard (DES)\r\n (N) A U.S. Government standard [FP046] that specifies the DEA and\r\n states policy for using the algorithm to protect unclassified,\r\n sensitive data. (See: AES.)\r\n $ data integrity\r\n 1. (I) The property that data has not been changed, destroyed, or\r\n lost in an unauthorized or accidental manner. (See: data integrity\r\n service. Compare: correctness integrity, source integrity.)\r\n 2. (O) \"The property that information has not been modified or\r\n destroyed in an unauthorized manner.\" [I7498-2]\r\n Usage: Deals with (a) constancy of and confidence in data values,\r\n and not with either (b) information that the values represent\r\n (see: correctness integrity) or (c) the trustworthiness of the\r\n source of the values (see: source integrity).\r\n $ data integrity service\r\n (I) A security service that protects against unauthorized changes\r\n to data, including both intentional change or destruction and\r\n accidental change or loss, by ensuring that changes to data are\r\n detectable. (See: data integrity, checksum, datagram integrity\r\n service.)\r\n Tutorial: A data integrity service can only detect a change and\r\n report it to an appropriate system entity; changes cannot be\r\n prevented unless the system is perfect (error-free) and no\r\n malicious user has access. However, a system that offers data\r\n integrity service might also attempt to correct and recover from\r\n changes.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 113 of 436\n\nThe ability of this service to detect changes is limited by the\r\n technology of the mechanisms used to implement the service. For\r\n example, if the mechanism were a one-bit parity check across each\r\n entire SDU, then changes to an odd number of bits in an SDU would\r\n be detected, but changes to an even number of bits would not.\r\n Relationship between data integrity service and authentication\r\n services: Although data integrity service is defined separately\r\n from data origin authentication service and peer entity\r\n authentication service, it is closely related to them.\r\n Authentication services depend, by definition, on companion data\r\n integrity services. Data origin authentication service provides\r\nShirey Informational [Page 95]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n verification that the identity of the original source of a\r\n received data unit is as claimed; there can be no such\r\n verification if the data unit has been altered. Peer entity\r\n authentication service provides verification that the identity of\r\n a peer entity in a current association is as claimed; there can be\r\n no such verification if the claimed identity has been altered.\r\n $ data origin authentication\r\n (I) \"The corroboration that the source of data received is as\r\n claimed.\" [I7498-2] (See: authentication.)\r\n $ data origin authentication service\r\n (I) A security service that verifies the identity of a system\r\n entity that is claimed to be the original source of received data.\r\n (See: authentication, authentication service.)\r\n Tutorial: This service is provided to any system entity that\r\n receives or holds the data. Unlike peer entity authentication\r\n service, this service is independent of any association between\r\n the originator and the recipient, and the data in question may\r\n have originated at any time in the past.\r\n A digital signature mechanism can be used to provide this service,\r\n because someone who does not know the private key cannot forge the\r\n correct signature. However, by using the signer's public key,\r\n anyone can verify the origin of correctly signed data.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 114 of 436\n\nThis service is usually bundled with connectionless data integrity\r\n service. (See: \"relationship between data integrity service and\r\n authentication services\" under \"data integrity service\".\r\n $ data owner\r\n (N) The organization that has the final statutory and operational\r\n authority for specified information.\r\n $ data privacy\r\n (D) Synonym for \"data confidentiality\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it mixes concepts\r\n in a potentially misleading way. Instead, use either \"data\r\n confidentiality\" or \"privacy\" or both, depending on what is meant.\r\n $ data recovery\r\n 1. (I) /cryptanalysis/ A process for learning, from some cipher\r\n text, the plain text that was previously encrypted to produce the\r\n cipher text. (See: recovery.)\r\nShirey Informational [Page 96]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /system integrity/ The process of restoring information\r\n following damage or destruction.\r\n $ data security\r\n (I) The protection of data from disclosure, alteration,\r\n destruction, or loss that either is accidental or is intentional\r\n but unauthorized.\r\n Tutorial: Both data confidentiality service and data integrity\r\n service are needed to achieve data security.\r\n $ datagram\r\n (I) \"A self-contained, independent entity of data [i.e., a packet]\r\n carrying sufficient information to be routed from the source\r\n [computer] to the destination computer without reliance on earlier\r\n exchanges between this source and destination computer and the\r\n transporting network.\" [R1983] Example: A PDU of IP.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 115 of 436\n\n$ datagram confidentiality service\r\n (I) A data confidentiality service that preserves the\r\n confidentiality of data in a single, independent, packet; i.e.,\r\n the service applies to datagrams one-at-a-time. Example: ESP.\r\n (See: data confidentiality.)\r\n Usage: When a protocol is said to provide data confidentiality\r\n service, this is usually understood to mean that only the SDU is\r\n protected in each packet. IDOCs that use the term to mean that the\r\n entire PDU is protected should include a highlighted definition.\r\n Tutorial: This basic form of network confidentiality service\r\n suffices for protecting the data in a stream of packets in both\r\n connectionless and connection-oriented protocols. Except perhaps\r\n for traffic flow confidentiality, nothing further is needed to\r\n protect the confidentiality of data carried by a packet stream.\r\n The OSIRM distinguishes between connection confidentiality and\r\n connectionless confidentiality. The IPS need not make that\r\n distinction, because those services are just instances of the same\r\n service (i.e., datagram confidentiality) being offered in two\r\n different protocol contexts. (For data integrity service, however,\r\n additional effort is needed to protect a stream, and the IPS does\r\n need to distinguish between \"datagram integrity service\" and\r\n \"stream integrity service\".)\r\n $ datagram integrity service\r\n (I) A data integrity service that preserves the integrity of data\r\n in a single, independent, packet; i.e., the service applies to\r\n datagrams one-at-a-time. (See: data integrity. Compare: stream\r\n integrity service.)\r\nShirey Informational [Page 97]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: The ability to provide appropriate data integrity is\r\n important in many Internet security situations, and so there are\r\n different kinds of data integrity services suited to different\r\n applications. This service is the simplest kind; it is suitable\r\n for connectionless data transfers.\r\n Datagram integrity service usually is designed only to attempt to\r\n detect changes to the SDU in each packet, but it might also\r\n attempt to detect changes to some or all of the PCI in each packet\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 116 of 436\n\n(see: selective field integrity). In contrast to this simple,\r\n one-at-a-time service, some security situations demand a more\r\n complex service that also attempts to detect deleted, inserted, or\r\n reordered datagrams within a stream of datagrams (see: stream\r\n integrity service).\r\n $ DEA\r\n (N) See: Data Encryption Algorithm.\r\n $ deception\r\n (I) A circumstance or event that may result in an authorized\r\n entity receiving false data and believing it to be true. (See:\r\n authentication.)\r\n Tutorial: This is a type of threat consequence, and it can be\r\n caused by the following types of threat actions: masquerade,\r\n falsification, and repudiation.\r\n $ decipher\r\n (D) Synonym for \"decrypt\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"decrypt\". However, see usage note under \"encryption\".\r\n $ decipherment\r\n (D) Synonym for \"decryption\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"decryption\". However, see the Usage note under \"encryption\".\r\n $ declassification\r\n (I) An authorized process by which information is declassified.\r\n (Compare: classification.)\r\n $ declassify\r\n (I) To officially remove the security level designation of a\r\n classified information item or information type, such that the\r\n information is no longer classified (i.e., becomes unclassified).\r\n (See: classified, classify, security level. Compare: downgrade.)\r\nShirey Informational [Page 98]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 117 of 436\n\n$ decode\r\n 1. (I) Convert encoded data back to its original form of\r\n representation. (Compare: decrypt.)\r\n 2. (D) Synonym for \"decrypt\".\r\n Deprecated Definition: Encoding is not usually meant to conceal\r\n meaning. Therefore, IDOCs SHOULD NOT use this term as a synonym\r\n for \"decrypt\", because that would mix concepts in a potentially\r\n misleading way.\r\n $ decrypt\r\n (I) Cryptographically restore cipher text to the plaintext form it\r\n had before encryption.\r\n $ decryption\r\n (I) See: secondary definition under \"encryption\".\r\n $ dedicated security mode\r\n (I) A mode of system operation wherein all users having access to\r\n the system possess, for all data handled by the system, both (a)\r\n all necessary authorizations (i.e., security clearance and formal\r\n access approval) and (b) a need-to-know. (See: /system operation/\r\n under \"mode\", formal access approval, need to know, protection\r\n level, security clearance.)\r\n Usage: Usually abbreviated as \"dedicated mode\". This mode was\r\n defined in U.S. Government policy on system accreditation, but the\r\n term is also used outside the Government. In this mode, the system\r\n may handle either (a) a single classification level or category of\r\n information or (b) a range of levels and categories.\r\n $ default account\r\n (I) A system login account (usually accessed with a user\r\n identifier and password) that has been predefined in a\r\n manufactured system to permit initial access when the system is\r\n first put into service. (See: harden.)\r\n Tutorial: A default account becomes a serious vulnerability if not\r\n properly administered. Sometimes, the default identifier and\r\n password are well-known because they are the same in each copy of\r\n the system. In any case, when a system is put into service, any\r\n default password should immediately be changed or the default\r\n account should be disabled.\r\n $ defense in depth\r\n (N) \"The siting of mutually supporting defense positions designed\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 118 of 436\n\nto absorb and progressively weaken attack, prevent initial\r\nShirey Informational [Page 99]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n observations of the whole position by the enemy, and [enable] the\r\n commander to maneuver the reserve.\" [JP1]\r\n Tutorial: In information systems, defense in depth means\r\n constructing a system's security architecture with layered and\r\n complementary security mechanisms and countermeasures, so that if\r\n one security mechanism is defeated, one or more other mechanisms\r\n (which are \"behind\" or \"beneath\" the first mechanism) still\r\n provide protection.\r\n This architectural concept is appealing because it aligns with\r\n traditional warfare doctrine, which applies defense in depth to\r\n physical, geospatial structures; but applying the concept to\r\n logical, cyberspace structures of computer networks is more\r\n difficult. The concept assumes that networks have a spatial or\r\n topological representation. It also assumes that there can be\r\n implemented -- from the \"outer perimeter\" of a network, through\r\n its various \"layers\" of components, to its \"center\" (i.e., to the\r\n subscriber application systems supported by the network) -- a\r\n varied series of countermeasures that together provide adequate\r\n protection. However, it is more difficult to map the topology of\r\n networks and make certain that no path exists by which an attacker\r\n could bypass all defensive layers.\r\n $ Defense Information Infrastructure (DII)\r\n (O) /U.S. DoD/ The U.S. DoD's shared, interconnected system of\r\n computers, communications, data, applications, security, people,\r\n training, and support structures, serving information needs\r\n worldwide. (See: DISN.) Usage: Has evolved to be called the GIG.\r\n Tutorial: The DII connects mission support, command and control,\r\n and intelligence computers and users through voice, data, imagery,\r\n video, and multimedia services, and provides information\r\n processing and value-added services to subscribers over the DISN.\r\n Users' own data and application software are not considered part\r\n of the DII.\r\n $ Defense Information Systems Network (DISN)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 119 of 436\n\n(O) /U.S. DoD/ The U.S. DoD's consolidated, worldwide, enterprise\r\n level telecommunications infrastructure that provides end-to-end\r\n information transfer for supporting military operations; a part of\r\n the DII. (Compare: GIG.)\r\n $ degauss\r\n 1a. (N) Apply a magnetic field to permanently remove data from a\r\n magnetic storage medium, such as a tape or disk [NCS25]. (Compare:\r\n erase, purge, sanitize.)\r\nShirey Informational [Page 100]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 1b. (N) Reduce magnetic flux density to zero by applying a\r\n reversing magnetic field. (See: magnetic remanence.)\r\n $ degausser\r\n (N) An electrical device that can degauss magnetic storage media.\r\n $ DEK\r\n (I) See: data encryption key.\r\n $ delay\r\n (I) /packet/ See: secondary definition under \"stream integrity\r\n service\".\r\n $ deletion\r\n (I) /packet/ See: secondary definition under \"stream integrity\r\n service\".\r\n $ deliberate exposure\r\n (I) /threat action/ See: secondary definition under \"exposure\".\r\n $ delta CRL\r\n (I) A partial CRL that only contains entries for certificates that\r\n have been revoked since the issuance of a prior, base CRL [X509].\r\n This method can be used to partition CRLs that become too large\r\n and unwieldy. (Compare: CRL distribution point.)\r\n $ demilitarized zone (DMZ)\r\n (D) Synonym for \"buffer zone\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 120 of 436\n\nDeprecated Term: IDOCs SHOULD NOT use this term because it mixes\r\n concepts in a potentially misleading way. (See: Deprecated Usage\r\n under \"Green Book\".)\r\n $ denial of service\r\n (I) The prevention of authorized access to a system resource or\r\n the delaying of system operations and functions. (See:\r\n availability, critical, flooding.)\r\n Tutorial: A denial-of-service attack can prevent the normal\r\n conduct of business on the Internet. There are four types of\r\n solutions to this security problem:\r\n - Awareness: Maintaining cognizance of security threats and\r\n vulnerabilities. (See: CERT.)\r\n - Detection: Finding attacks on end systems and subnetworks.\r\n (See: intrusion detection.)\r\n - Prevention: Following defensive practices on network-connected\r\n systems. (See: [R2827].)\r\nShirey Informational [Page 101]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - Response: Reacting effectively when attacks occur. (See: CSIRT,\r\n contingency plan.)\r\n $ DES\r\n (N) See: Data Encryption Standard.\r\n $ designated approving authority (DAA)\r\n (O) /U.S. Government/ Synonym for \"accreditor\".\r\n $ detection\r\n (I) See: secondary definition under \"security\".\r\n $ deterrence\r\n (I) See: secondary definition under \"security\".\r\n $ dictionary attack\r\n (I) An attack that uses a brute-force technique of successively\r\n trying all the words in some large, exhaustive list.\r\n Examples: Attack an authentication service by trying all possible\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 121 of 436\n\npasswords. Attack an encryption service by encrypting some known\r\n plaintext phrase with all possible keys so that the key for any\r\n given encrypted message containing that phrase may be obtained by\r\n lookup.\r\n $ Diffie-Hellman\r\n $ Diffie-Hellman-Merkle\r\n (N) A key-agreement algorithm published in 1976 by Whitfield\r\n Diffie and Martin Hellman [DH76, R2631].\r\n Usage: The algorithm is most often called \"Diffie-Hellman\".\r\n However, in the November 1978 issue of \"IEEE Communications\r\n Magazine\", Hellman wrote that the algorithm \"is a public key\r\n distribution system, a concept developed by [Ralph C.] Merkle, and\r\n hence should be called 'Diffie-Hellman-Merkle' ... to recognize\r\n Merkle's equal contribution to the invention of public key\r\n cryptography.\"\r\n Tutorial: Diffie-Hellman-Merkle does key establishment, not\r\n encryption. However, the key that it produces may be used for\r\n encryption, for further key management operations, or for any\r\n other cryptography.\r\n The algorithm is described in [R2631] and [Schn]. In brief, Alice\r\n and Bob together pick large integers that satisfy certain\r\n mathematical conditions, and then use the integers to each\r\n separately compute a public-private key pair. They send each other\r\n their public key. Each person uses their own private key and the\r\nShirey Informational [Page 102]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n other person's public key to compute a key, k, that, because of\r\n the mathematics of the algorithm, is the same for each of them.\r\n Passive wiretapping cannot learn the shared k, because k is not\r\n transmitted, and neither are the private keys needed to compute k.\r\n The difficulty of breaking Diffie-Hellman-Merkle is considered to\r\n be equal to the difficulty of computing discrete logarithms modulo\r\n a large prime. However, without additional mechanisms to\r\n authenticate each party to the other, a protocol based on the\r\n algorithm may be vulnerable to a man-in-the-middle attack.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 122 of 436\n\n$ digest\r\n See: message digest.\r\n $ digital certificate\r\n (I) A certificate document in the form of a digital data object (a\r\n data object used by a computer) to which is appended a computed\r\n digital signature value that depends on the data object. (See:\r\n attribute certificate, public-key certificate.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term to refer to a\r\n signed CRL or CKL. Although the recommended definition can be\r\n interpreted to include other signed items, the security community\r\n does not use the term with those meanings.\r\n $ digital certification\r\n (D) Synonym for \"certification\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this definition unless\r\n the context is not sufficient to distinguish between digital\r\n certification and another kind of certification, in which case it\r\n would be better to use \"public-key certification\" or another\r\n phrase that indicates what is being certified.\r\n $ digital document\r\n (I) An electronic data object that represents information\r\n originally written in a non-electronic, non-magnetic medium\r\n (usually ink on paper) or is an analogue of a document of that\r\n type.\r\n $ digital envelope\r\n (I) A combination of (a) encrypted content data (of any kind)\r\n intended for a recipient and (b) the content encryption key in an\r\n encrypted form that has been prepared for the use of the\r\n recipient.\r\nShirey Informational [Page 103]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: In IDOCs, the term SHOULD be defined at the point of first\r\n use because, although the term is defined in PKCS #7 and used in\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 123 of 436\n\nS/MIME, it is not widely known.\r\n Tutorial: Digital enveloping is not simply a synonym for\r\n implementing data confidentiality with encryption; digital\r\n enveloping is a hybrid encryption scheme to \"seal\" a message or\r\n other data, by encrypting the data and sending both it and a\r\n protected form of the key to the intended recipient, so that no\r\n one other than the intended recipient can \"open\" the message. In\r\n PKCS #7, it means first encrypting the data using a symmetric\r\n encryption algorithm and a secret key, and then encrypting the\r\n secret key using an asymmetric encryption algorithm and the public\r\n key of the intended recipient. In S/MIME, additional methods are\r\n defined for encrypting the content encryption key.\r\n $ Digital ID(service mark)\r\n (D) Synonym for \"digital certificate\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term. It is a service\r\n mark of a commercial firm, and it unnecessarily duplicates the\r\n meaning of a better-established term. (See: credential.)\r\n $ digital key\r\n (D) Synonym for an input parameter of a cryptographic algorithm or\r\n other process. (See: key.)\r\n Deprecated Usage: The adjective \"digital\" need not be used with\r\n \"key\" or \"cryptographic key\", unless the context is insufficient\r\n to distinguish the digital key from another kind of key, such as a\r\n metal key for a door lock.\r\n $ digital notary\r\n (I) An electronic functionary analogous to a notary public.\r\n Provides a trusted timestamp for a digital document, so that\r\n someone can later prove that the document existed at that point in\r\n time; verifies the signature(s) on a signed document before\r\n applying the stamp. (See: notarization.)\r\n $ digital signature\r\n 1. (I) A value computed with a cryptographic algorithm and\r\n associated with a data object in such a way that any recipient of\r\n the data can use the signature to verify the data's origin and\r\n integrity. (See: data origin authentication service, data\r\n integrity service, signer. Compare: digitized signature,\r\n electronic signature.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 124 of 436\n\nShirey Informational [Page 104]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) \"Data appended to, or a cryptographic transformation of, a\r\n data unit that allows a recipient of the data unit to prove the\r\n source and integrity of the data unit and protect against forgery,\r\n e.g. by the recipient.\" [I7498-2]\r\n Tutorial: A digital signature should have these properties:\r\n - Be capable of being verified. (See: validate vs. verify.)\r\n - Be bound to the signed data object in such a way that if the\r\n data is changed, then when an attempt is made to verify the\r\n signature, it will be seen as not authentic. (In some schemes,\r\n the signature is appended to the signed object as stated by\r\n definition 2, but in other it, schemes is not.)\r\n - Uniquely identify a system entity as being the signer.\r\n - Be under the signer's sole control, so that it cannot be\r\n created by any other entity.\r\n To achieve these properties, the data object is first input to a\r\n hash function, and then the hash result is cryptographically\r\n transformed using a private key of the signer. The final resulting\r\n value is called the digital signature of the data object. The\r\n signature value is a protected checksum, because the properties of\r\n a cryptographic hash ensure that if the data object is changed,\r\n the digital signature will no longer match it. The digital\r\n signature is unforgeable because one cannot be certain of\r\n correctly creating or changing the signature without knowing the\r\n private key of the supposed signer.\r\n Some digital signature schemes use an asymmetric encryption\r\n algorithm (e.g., \"RSA\") to transform the hash result. Thus, when\r\n Alice needs to sign a message to send to Bob, she can use her\r\n private key to encrypt the hash result. Bob receives both the\r\n message and the digital signature. Bob can use Alice's public key\r\n to decrypt the signature, and then compare the plaintext result to\r\n the hash result that he computes by hashing the message himself.\r\n If the values are equal, Bob accepts the message because he is\r\n certain that it is from Alice and has arrived unchanged. If the\r\n values are not equal, Bob rejects the message because either the\r\n message or the signature was altered in transit.\r\n Other digital signature schemes (e.g., \"DSS\") transform the hash\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 125 of 436\n\nresult with an algorithm (e.g., \"DSA\", \"El Gamal\") that cannot be\r\n directly used to encrypt data. Such a scheme creates a signature\r\n value from the hash and provides a way to verify the signature\r\n value, but does not provide a way to recover the hash result from\r\n the signature value. In some countries, such a scheme may improve\r\n exportability and avoid other legal constraints on usage. Alice\r\n sends the signature value to Bob along with both the message and\r\n its hash result. The algorithm enables Bob to use Alice's public\r\nShirey Informational [Page 105]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n signature key and the signature value to verify the hash result he\r\n receives. Then, as before, he compares that hash result she sent\r\n to the one that he computes by hashing the message himself.\r\n $ Digital Signature Algorithm (DSA)\r\n (N) An asymmetric cryptographic algorithm for a digital signature\r\n in the form of a pair of large numbers. The signature is computed\r\n using rules and parameters such that the identity of the signer\r\n and the integrity of the signed data can be verified. (See: DSS.)\r\n $ Digital Signature Standard (DSS)\r\n (N) The U.S. Government standard [FP186] that specifies the DSA.\r\n $ digital watermarking\r\n (I) Computing techniques for inseparably embedding unobtrusive\r\n marks or labels as bits in digital data -- text, graphics, images,\r\n video, or audio -- and for detecting or extracting the marks\r\n later.\r\n Tutorial: A \"digital watermark\", i.e., the set of embedded bits,\r\n is sometimes hidden, usually imperceptible, and always intended to\r\n be unobtrusive. Depending on the particular technique that is\r\n used, digital watermarking can assist in proving ownership,\r\n controlling duplication, tracing distribution, ensuring data\r\n integrity, and performing other functions to protect intellectual\r\n property rights. [ACM]\r\n $ digitized signature\r\n (D) Denotes various forms of digitized images of handwritten\r\n signatures. (Compare: digital signature).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 126 of 436\n\nDeprecated Term: IDOCs SHOULD NOT use this term without including\r\n this definition. This term suggests careless use of \"digital\r\n signature\", which is the term standardized by [I7498-2]. (See:\r\n electronic signature.)\r\n $ DII\r\n (O) See: Defense Information Infrastructure.\r\n $ direct attack\r\n (I) See: secondary definition under \"attack\". (Compare: indirect\r\n attack.)\r\n $ directory, Directory\r\n 1. (I) /not capitalized/ Refers generically to a database server\r\n or other system that stores and provides access to values of\r\n descriptive or operational data items that are associated with the\r\n components of a system. (Compare: repository.)\r\nShirey Informational [Page 106]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (N) /capitalized/ Refers specifically to the X.500 Directory.\r\n (See: DN, X.500.)\r\n $ Directory Access Protocol (DAP)\r\n (N) An OSI protocol [X519] for communication between a Directory\r\n User Agent (a type of X.500 client) and a Directory System Agent\r\n (a type of X.500 server). (See: LDAP.)\r\n $ disaster plan\r\n (O) Synonym for \"contingency plan\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; instead, for\r\n consistency and neutrality of language, IDOCs SHOULD use\r\n \"contingency plan\".\r\n $ disclosure\r\n See: unauthorized disclosure. Compare: exposure.\r\n $ discretionary access control\r\n 1a. (I) An access control service that (a) enforces a security\r\n policy based on the identity of system entities and the\r\n authorizations associated with the identities and (b) incorporates\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 127 of 436\n\na concept of ownership in which access rights for a system\r\n resource may be granted and revoked by the entity that owns the\r\n resource. (See: access control list, DAC, identity-based security\r\n policy, mandatory access control.)\r\n Derivation: This service is termed \"discretionary\" because an\r\n entity can be granted access rights to a resource such that the\r\n entity can by its own volition enable other entities to access the\r\n resource.\r\n 1b. (O) /formal model/ \"A means of restricting access to objects\r\n based on the identity of subjects and/or groups to which they\r\n belong. The controls are discretionary in the sense that a subject\r\n with a certain access permission is capable of passing that\r\n permission (perhaps indirectly) on to any other subject.\" [DoD1]\r\n $ DISN\r\n (O) See: Defense Information Systems Network (DISN).\r\n $ disruption\r\n (I) A circumstance or event that interrupts or prevents the\r\n correct operation of system services and functions. (See:\r\n availability, critical, system integrity, threat consequence.)\r\nShirey Informational [Page 107]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Disruption is a type of threat consequence; it can be\r\n caused by the following types of threat actions: incapacitation,\r\n corruption, and obstruction.\r\n $ Distinguished Encoding Rules (DER)\r\n (N) A subset of the Basic Encoding Rules that always provides only\r\n one way to encode any data structure defined by ASN.1. [X690].\r\n Tutorial: For a data structure defined abstractly in ASN.1, BER\r\n often provides for encoding the structure into an octet string in\r\n more than one way, so that two separate BER implementations can\r\n legitimately produce different octet strings for the same ASN.1\r\n definition. However, some applications require all encodings of a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 128 of 436\n\nstructure to be the same, so that encodings can be compared for\r\n equality. Therefore, DER is used in applications in which unique\r\n encoding is needed, such as when a digital signature is computed\r\n on a structure defined by ASN.1.\r\n $ distinguished name (DN)\r\n (N) An identifier that uniquely represents an object in the X.500\r\n Directory Information Tree (DIT) [X501]. (Compare: domain name,\r\n identity, naming authority.)\r\n Tutorial: A DN is a set of attribute values that identify the path\r\n leading from the base of the DIT to the object that is named. An\r\n X.509 public-key certificate or CRL contains a DN that identifies\r\n its issuer, and an X.509 attribute certificate contains a DN or\r\n other form of name that identifies its subject.\r\n $ distributed attack\r\n 1a. (I) An attack that is implemented with distributed computing.\r\n (See: zombie.)\r\n 1b. (I) An attack that deploys multiple threat agents.\r\n $ Distributed Authentication Security Service (DASS)\r\n (I) An experimental Internet protocol [R1507] that uses\r\n cryptographic mechanisms to provide strong, mutual authentication\r\n services in a distributed environment.\r\n $ distributed computing\r\n (I) A technique that disperses a single, logically related set of\r\n tasks among a group of geographically separate yet cooperating\r\n computers. (See: distributed attack.)\r\nShirey Informational [Page 108]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ distribution point\r\n (I) An X.500 Directory entry or other information source that is\r\n named in a v3 X.509 public-key certificate extension as a location\r\n from which to obtain a CRL that may list the certificate.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 129 of 436\n\nTutorial: A v3 X.509 public-key certificate may have a\r\n \"cRLDistributionPoints\" extension that names places to get CRLs on\r\n which the certificate might be listed. (See: certificate profile.)\r\n A CRL obtained from a distribution point may (a) cover either all\r\n reasons for which a certificate might be revoked or only some of\r\n the reasons, (b) be issued by either the authority that signed the\r\n certificate or some other authority, and (c) contain revocation\r\n entries for only a subset of the full set of certificates issued\r\n by one CA or (d) contain revocation entries for multiple CAs.\r\n $ DKIM\r\n (I) See: Domain Keys Identified Mail.\r\n $ DMZ\r\n (D) See: demilitarized zone.\r\n $ DN\r\n (N) See: distinguished name.\r\n $ DNS\r\n (I) See: Domain Name System.\r\n $ doctrine\r\n See: security doctrine.\r\n $ DoD\r\n (N) Department of Defense.\r\n Usage: To avoid international misunderstanding, IDOCs SHOULD use\r\n this abbreviation only with a national qualifier (e.g., U.S. DoD).\r\n $ DOI\r\n (I) See: Domain of Interpretation.\r\n $ domain\r\n 1a. (I) /general security/ An environment or context that (a)\r\n includes a set of system resources and a set of system entities\r\n that have the right to access the resources and (b) usually is\r\n defined by a security policy, security model, or security\r\n architecture. (See: CA domain, domain of interpretation, security\r\n perimeter. Compare: COI, enclave.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 130 of 436\n\nShirey Informational [Page 109]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: A \"controlled interface\" or \"guard\" is required to\r\n transfer information between network domains that operate under\r\n different security policies.\r\n 1b. (O) /security policy/ A set of users, their information\r\n objects, and a common security policy. [DoD6, SP33]\r\n 1c. (O) /security policy/ A system or collection of systems that\r\n (a) belongs to a community of interest that implements a\r\n consistent security policy and (b) is administered by a single\r\n authority.\r\n 2. (O) /COMPUSEC/ An operating state or mode of a set of computer\r\n hardware.\r\n Tutorial: Most computers have at least two hardware operating\r\n modes [Gass]:\r\n - \"Privileged\" mode: a.k.a. \"executive\", \"master\", \"system\",\r\n \"kernel\", or \"supervisor\" mode. In this mode, software can\r\n execute all machine instructions and access all storage\r\n locations.\r\n - \"Unprivileged\" mode: a.k.a. \"user\", \"application\", or \"problem\"\r\n mode. In this mode, software is restricted to a subset of the\r\n instructions and a subset of the storage locations.\r\n 3. (O) \"A distinct scope within which certain common\r\n characteristics are exhibited and common rules are observed.\"\r\n [CORBA]\r\n 4. (O) /MISSI/ The domain of a MISSI CA is the set of MISSI users\r\n whose certificates are signed by the CA.\r\n 5. (I) /Internet/ That part of the tree-structured name space of\r\n the DNS that is at or below the name that specifies the domain. A\r\n domain is a subdomain of another domain if it is contained within\r\n that domain. For example, D.C.B.A is a subdomain of C.B.A\r\n 6. (O) /OSI/ An administrative partition of a complex distributed\r\n OSI system.\r\n $ Domain Keys Identified Mail (DKIM)\r\n (I) A protocol, which is being specified by the IETF working group\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 131 of 436\n\nof the same name, to provide data integrity and domain-level (see:\r\n DNS, domain name) data origin authentication for Internet mail\r\n messages. (Compare: PEM.)\r\n Tutorial: DKIM employs asymmetric cryptography to create a digital\r\n signature for an Internet email message's body and selected\r\nShirey Informational [Page 110]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n headers (see RFC 1822), and the signature is then carried in a\r\n header of the message. A recipient of the message can verify the\r\n signature and, thereby, authenticate the identity of the\r\n originating domain and the integrity of the signed content, by\r\n using a public key belonging to the domain. The key can be\r\n obtained from the DNS.\r\n $ domain name\r\n (I) The style of identifier that is defined for subtrees in the\r\n Internet DNS -- i.e., a sequence of case-insensitive ASCII labels\r\n separated by dots (e.g., \"bbn.com\") -- and also is used in other\r\n types of Internet identifiers, such as host names (e.g.,\r\n \"rosslyn.bbn.com\"), mailbox names (e.g., \"rshirey@bbn.com\") and\r\n URLs (e.g., \"http://www.rosslyn.bbn.com/foo\"). (See: domain.\r\n Compare: DN.)\r\n Tutorial: The name space of the DNS is a tree structure in which\r\n each node and leaf holds records describing a resource. Each node\r\n has a label. The domain name of a node is the list of labels on\r\n the path from the node to the root of the tree. The labels in a\r\n domain name are printed or read left to right, from the most\r\n specific (lowest, farthest from the root) to the least specific\r\n (highest, closest to the root), but the root's label is the null\r\n string. (See: country code.)\r\n $ Domain Name System (DNS)\r\n (I) The main Internet operations database, which is distributed\r\n over a collection of servers and used by client software for\r\n purposes such as (a) translating a domain name-style host name\r\n into an IP address (e.g., \"rosslyn.bbn.com\" translates to\r\n \"192.1.7.10\") and (b) locating a host that accepts mail for a\r\n given mailbox address. (RFC 1034) (See: domain name.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 132 of 436\n\nTutorial: The DNS has three major components:\r\n - Domain name space and resource records: Specifications for the\r\n tree-structured domain name space, and data associated with the\r\n names.\r\n - Name servers: Programs that hold information about a subset of\r\n the tree's structure and data holdings, and also hold pointers\r\n to other name servers that can provide information from any\r\n part of the tree.\r\n - Resolvers: Programs that extract information from name servers\r\n in response to client requests; typically, system routines\r\n directly accessible to user programs.\r\n Extensions to the DNS [R4033, R4034, R4035] support (a) key\r\n distribution for public keys needed for the DNS and for other\r\n protocols, (b) data origin authentication service and data\r\nShirey Informational [Page 111]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n integrity service for resource records, (c) data origin\r\n authentication service for transactions between resolvers and\r\n servers, and (d) access control of records.\r\n $ domain of interpretation (DOI)\r\n (I) /IPsec/ A DOI for ISAKMP or IKE defines payload formats,\r\n exchange types, and conventions for naming security-relevant\r\n information such as security policies or cryptographic algorithms\r\n and modes. Example: See [R2407].\r\n Derivation: The DOI concept is based on work by the TSIG's CIPSO\r\n Working Group.\r\n $ dominate\r\n (I) Security level A is said to \"dominate\" security level B if the\r\n (hierarchical) classification level of A is greater (higher) than\r\n or equal to that of B, and A's (nonhierarchical) categories\r\n include (as a subset) all of B's categories. (See: lattice,\r\n lattice model.)\r\n $ dongle\r\n (I) A portable, physical, usually electronic device that is\r\n required to be attached to a computer to enable a particular\r\n software program to run. (See: token.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 133 of 436\n\nTutorial: A dongle is essentially a physical key used for copy\r\n protection of software; that is, the program will not run unless\r\n the matching dongle is attached. When the software runs, it\r\n periodically queries the dongle and quits if the dongle does not\r\n reply with the proper authentication information. Dongles were\r\n originally constructed as an EPROM (erasable programmable read-\r\n only memory) to be connected to a serial input-output port of a\r\n personal computer.\r\n $ downgrade\r\n (I) /data security/ Reduce the security level of data (especially\r\n the classification level) without changing the information content\r\n of the data. (Compare: downgrade.)\r\n $ downgrade attack\r\n (I) A type of man-in-the-middle attack in which the attacker can\r\n cause two parties, at the time they negotiate a security\r\n association, to agree on a lower level of protection than the\r\n highest level that could have been supported by both of them.\r\n (Compare: downgrade.)\r\nShirey Informational [Page 112]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ draft RFC\r\n (D) A preliminary, temporary version of a document that is\r\n intended to become an RFC. (Compare: Internet-Draft.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term. The RFC series is\r\n archival in nature and consists only of documents in permanent\r\n form. A document that is intended to become an RFC usually needs\r\n to be published first as an Internet-Draft (RFC 2026). (See:\r\n \"Draft Standard\" under \"Internet Standard\".)\r\n $ Draft Standard\r\n (I) See: secondary definition under \"Internet Standard\".\r\n $ DSA\r\n (N) See: Digital Signature Algorithm.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 134 of 436\n\n$ DSS\r\n (N) See: Digital Signature Standard.\r\n $ dual control\r\n (I) A procedure that uses two or more entities (usually persons)\r\n operating in concert to protect a system resource, such that no\r\n single entity acting alone can access that resource. (See: no-lone\r\n zone, separation of duties, split knowledge.)\r\n $ dual signature\r\n (O) /SET/ A single digital signature that protects two separate\r\n messages by including the hash results for both sets in a single\r\n encrypted value. [SET2]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term except when\r\n qualified as \"SET(trademark) dual signature\" with this definition.\r\n Tutorial: Generated by hashing each message separately,\r\n concatenating the two hash results, and then hashing that value\r\n and encrypting the result with the signer's private key. Done to\r\n reduce the number of encryption operations and to enable\r\n verification of data integrity without complete disclosure of the\r\n data.\r\n $ dual-use certificate\r\n (O) A certificate that is intended for use with both digital\r\n signature and data encryption services. [SP32]\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n by identifying the intended uses of the certificate, because there\r\n are more than just these two uses mentioned in the NIST\r\n publication. A v3 X.509 public-key certificate may have a \"key\r\nShirey Informational [Page 113]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage\" extension, which indicates the purposes for which the\r\n public key may be used. (See: certificate profile.)\r\n $ duty\r\n (I) An attribute of a role that obligates an entity playing the\r\n role to perform one or more tasks, which usually are essential for\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 135 of 436\n\nthe functioning of the system. [Sand] (Compare authorization,\r\n privilege. See: role, billet.)\r\n $ e-cash\r\n (O) Electronic cash; money that is in the form of data and can be\r\n used as a payment mechanism on the Internet. (See: IOTP.)\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because many different types of electronic cash have been devised\r\n with a variety of security mechanisms.\r\n $ EAP\r\n (I) See: Extensible Authentication Protocol.\r\n $ EAL\r\n (O) See: evaluation assurance level.\r\n $ Easter egg\r\n (O) \"Hidden functionality within an application program, which\r\n becomes activated when an undocumented, and often convoluted, set\r\n of commands and keystrokes is entered. Easter eggs are typically\r\n used to display the credits for the development team and [are]\r\n intended to be non-threatening\" [SP28], but Easter eggs have the\r\n potential to contain malicious code.\r\n Deprecated Usage: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ eavesdropping\r\n (I) Passive wiretapping done secretly, i.e., without the knowledge\r\n of the originator or the intended recipients of the communication.\r\n $ ECB\r\n (N) See: electronic codebook.\r\n $ ECDSA\r\n (N) See: Elliptic Curve Digital Signature Algorithm.\r\nShirey Informational [Page 114]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 136 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ economy of alternatives\r\n (I) The principle that a security mechanism should be designed to\r\n minimize the number of alternative ways of achieving a service.\r\n (Compare: economy of mechanism.)\r\n $ economy of mechanism\r\n (I) The principle that a security mechanism should be designed to\r\n be as simple as possible, so that (a) the mechanism can be\r\n correctly implemented and (b) it can be verified that the\r\n operation of the mechanism enforces the system's security policy.\r\n (Compare: economy of alternatives, least privilege.)\r\n $ ECU\r\n (N) See: end cryptographic unit.\r\n $ EDI\r\n (I) See: electronic data interchange.\r\n $ EDIFACT\r\n (N) See: secondary definition under \"electronic data interchange\".\r\n $ EE\r\n (D) Abbreviation of \"end entity\" and other terms.\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use this abbreviation;\r\n there could be confusion among \"end entity\", \"end-to-end\r\n encryption\", \"escrowed encryption standard\", and other terms.\r\n $ EES\r\n (O) See: Escrowed Encryption Standard.\r\n $ effective key length\r\n (O) \"A measure of strength of a cryptographic algorithm,\r\n regardless of actual key length.\" [IATF] (See: work factor.)\r\n $ effectiveness\r\n (O) /ITSEC/ A property of a TOE representing how well it provides\r\n security in the context of its actual or proposed operational use.\r\n $ El Gamal algorithm\r\n (N) An algorithm for asymmetric cryptography, invented in 1985 by\r\n Taher El Gamal, that is based on the difficulty of calculating\r\n discrete logarithms and can be used for both encryption and\r\n digital signatures. [ElGa]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 137 of 436\n\nShirey Informational [Page 115]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ electronic codebook (ECB)\r\n (N) A block cipher mode in which a plaintext block is used\r\n directly as input to the encryption algorithm and the resultant\r\n output block is used directly as cipher text [FP081]. (See: block\r\n cipher, [SP38A].)\r\n $ electronic commerce\r\n 1. (I) Business conducted through paperless exchanges of\r\n information, using electronic data interchange, electronic funds\r\n transfer (EFT), electronic mail, computer bulletin boards,\r\n facsimile, and other paperless technologies.\r\n 2. (O) /SET/ \"The exchange of goods and services for payment\r\n between the cardholder and merchant when some or all of the\r\n transaction is performed via electronic communication.\" [SET2]\r\n $ electronic data interchange (EDI)\r\n (I) Computer-to-computer exchange, between trading partners, of\r\n business data in standardized document formats.\r\n Tutorial: EDI formats have been standardized primarily by ANSI X12\r\n and by EDIFACT (EDI for Administration, Commerce, and\r\n Transportation), which is an international, UN-sponsored standard\r\n primarily used in Europe and Asia. X12 and EDIFACT are aligning to\r\n create a single, global EDI standard.\r\n $ Electronic Key Management System (EKMS)\r\n (O) \"Interoperable collection of systems developed by ... the U.S.\r\n Government to automate the planning, ordering, generating,\r\n distributing, storing, filling, using, and destroying of\r\n electronic keying material and the management of other types of\r\n COMSEC material.\" [C4009]\r\n $ electronic signature\r\n (D) Synonym for \"digital signature\" or \"digitized signature\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 138 of 436\n\nDeprecated Term: IDOCs SHOULD NOT use this term; there is no\r\n current consensus on its definition. Instead, use \"digital\r\n signature\", if that is what was intended\r\n $ electronic wallet\r\n (D) A secure container to hold, in digitized form, some sensitive\r\n data objects that belong to the owner, such as electronic money,\r\n authentication material, and various types of personal\r\n information. (See: IOTP.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term. There is no\r\n current consensus on its definition; and some uses and definitions\r\nShirey Informational [Page 116]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n may be proprietary. Meanings range from virtual wallets\r\n implemented by data structures to physical wallets implemented by\r\n cryptographic tokens. (See: Deprecated Usage under \"Green Book\".)\r\n $ elliptic curve cryptography (ECC)\r\n (I) A type of asymmetric cryptography based on mathematics of\r\n groups that are defined by the points on a curve, where the curve\r\n is defined by a quadratic equation in a finite field. [Schn]\r\n Tutorial: ECC is based on mathematics different than that\r\n originally used to define the Diffie-Hellman-Merkle algorithm and\r\n the DSA, but ECC can be used to define an algorithm for key\r\n agreement that is an analog of Diffie-Hellman-Merkle [A9063] and\r\n an algorithm for digital signature that is an analog of DSA\r\n [A9062]. The mathematical problem upon which ECC is based is\r\n believed to be more difficult than the problem upon which Diffie-\r\n Hellman-Merkle is based and, therefore, that keys for ECC can be\r\n shorter for a comparable level of security. (See: ECDSA.)\r\n $ Elliptic Curve Digital Signature Algorithm (ECDSA)\r\n (N) A standard [A9062] that is the analog, in elliptic curve\r\n cryptography, of the Digital Signature Algorithm.\r\n $ emanation\r\n (I) A signal (e.g., electromagnetic or acoustic) that is emitted\r\n by a system (e.g., through radiation or conductance) as a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 139 of 436\n\nconsequence (i.e., byproduct) of the system's operation, and that\r\n may contain information. (See: emanations security.)\r\n $ emanations analysis\r\n (I) /threat action/ See: secondary definition under\r\n \"interception\".\r\n $ emanations security (EMSEC)\r\n (I) Physical security measures to protect against data compromise\r\n that could occur because of emanations that might be received and\r\n read by an unauthorized party. (See: emanation, TEMPEST.)\r\n Usage: Refers either to preventing or limiting emanations from a\r\n system and to preventing or limiting the ability of unauthorized\r\n parties to receive the emissions.\r\n $ embedded cryptography\r\n (N) \"Cryptography engineered into an equipment or system whose\r\n basic function is not cryptographic.\" [C4009]\r\n $ emergency plan\r\n (D) Synonym for \"contingency plan\".\r\nShirey Informational [Page 117]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term. Instead, for\r\n neutrality and consistency of language, use \"contingency plan\".\r\n $ emergency response\r\n (O) An urgent response to a fire, flood, civil commotion, natural\r\n disaster, bomb threat, or other serious situation, with the intent\r\n of protecting lives, limiting damage to property, and minimizing\r\n disruption of system operations. [FP087] (See: availability, CERT,\r\n emergency plan.)\r\n $ EMSEC\r\n (I) See: emanations security.\r\n $ EMV\r\n (N) Abbreviation of \"Europay, MasterCard, Visa\". Refers to a\r\n specification for smart cards that are used as payment cards, and\r\n for related terminals and applications. [EMV1, EMV2, EMV3]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 140 of 436\n\n$ Encapsulating Security Payload (ESP)\r\n (I) An Internet protocol [R2406, R4303] designed to provide data\r\n confidentiality service and other security services for IP\r\n datagrams. (See: IPsec. Compare: AH.)\r\n Tutorial: ESP may be used alone, or in combination with AH, or in\r\n a nested fashion with tunneling. Security services can be provided\r\n between a pair of communicating hosts, between a pair of\r\n communicating security gateways, or between a host and a gateway.\r\n The ESP header is encapsulated by the IP header, and the ESP\r\n header encapsulates either the upper-layer protocol header\r\n (transport mode) or an IP header (tunnel mode). ESP can provide\r\n data confidentiality service, data origin authentication service,\r\n connectionless data integrity service, an anti-replay service, and\r\n limited traffic-flow confidentiality. The set of services depends\r\n on the placement of the implementation and on options selected\r\n when the security association is established.\r\n $ encipher\r\n (D) Synonym for \"encrypt\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"encrypt\". However, see Usage note under \"encryption\".\r\n $ encipherment\r\n (D) Synonym for \"encryption\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"encryption\". However, see Usage note under \"encryption\".\r\nShirey Informational [Page 118]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ enclave\r\n 1. (I) A set of system resources that operate in the same security\r\n domain and that share the protection of a single, common,\r\n continuous security perimeter. (Compare: domain.)\r\n 2. (D) /U.S. Government/ \"Collection of computing environments\r\n connected by one or more internal networks under the control of a\r\n single authority and security policy, including personnel and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 141 of 436\n\nphysical security.\" [C4009]\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 2 because the definition applies to what is usually\r\n called a \"security domain\". That is, a security domain is a set of\r\n one or more security enclaves.\r\n $ encode\r\n 1. (I) Use a system of symbols to represent information, which\r\n might originally have some other representation. Example: Morse\r\n code. (See: ASCII, BER.) (See: code, decode.)\r\n 2. (D) Synonym for \"encrypt\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"encrypt\"; encoding is not always meant to conceal meaning.\r\n $ encrypt\r\n (I) Cryptographically transform data to produce cipher text. (See:\r\n encryption. Compare: seal.)\r\n $ encryption\r\n 1. (I) Cryptographic transformation of data (called \"plain text\")\r\n into a different form (called \"cipher text\") that conceals the\r\n data's original meaning and prevents the original form from being\r\n used. The corresponding reverse process is \"decryption\", a\r\n transformation that restores encrypted data to its original form.\r\n (See: cryptography.)\r\n 2. (O) \"The cryptographic transformation of data to produce\r\n ciphertext.\" [I7498-2]\r\n Usage: For this concept, IDOCs SHOULD use the verb \"to encrypt\"\r\n (and related variations: encryption, decrypt, and decryption).\r\n However, because of cultural biases involving human burial, some\r\n international documents (particularly ISO and CCITT standards)\r\n avoid \"to encrypt\" and instead use the verb \"to encipher\" (and\r\n related variations: encipherment, decipher, decipherment).\r\nShirey Informational [Page 119]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 142 of 436\n\nTutorial: Usually, the plaintext input to an encryption operation\r\n is clear text. But in some cases, the plain text may be cipher\r\n text that was output from another encryption operation. (See:\r\n superencryption.)\r\n Encryption and decryption involve a mathematical algorithm for\r\n transforming data. Besides the data to be transformed, the\r\n algorithm has one or more inputs that are control parameters: (a)\r\n a key that varies the transformation and, in some cases, (b) an IV\r\n that establishes the starting state of the algorithm.\r\n $ encryption certificate\r\n (I) A public-key certificate that contains a public key that is\r\n intended to be used for encrypting data, rather than for verifying\r\n digital signatures or performing other cryptographic functions.\r\n Tutorial: A v3 X.509 public-key certificate may have a \"keyUsage\"\r\n extension that indicates the purpose for which the certified\r\n public key is intended. (See: certificate profile.)\r\n $ end cryptographic unit (ECU)\r\n 1. (N) Final destination device into which a key is loaded for\r\n operational use.\r\n 2. (N) A device that (a) performs cryptographic functions, (b)\r\n typically is part of a larger system for which the device provides\r\n security services, and (c), from the viewpoint of a supporting\r\n security infrastructure such as a key management system, is the\r\n lowest level of identifiable component with which a management\r\n transaction can be conducted\r\n $ end entity\r\n 1. (I) A system entity that is the subject of a public-key\r\n certificate and that is using, or is permitted and able to use,\r\n the matching private key only for purposes other than signing a\r\n digital certificate; i.e., an entity that is not a CA.\r\n 2. (O) \"A certificate subject [that] uses its public [sic] key for\r\n purposes other than signing certificates.\" [X509]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 2, which is\r\n misleading and incomplete. First, that definition should have said\r\n \"private key\" rather than \"public key\" because certificates are\r\n not usefully signed with a public key. Second, the X.509\r\n definition is ambiguous regarding whether an end entity may or may\r\n not use the private key to sign a certificate, i.e., whether the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 143 of 436\n\nsubject may be a CA. The intent of X.509's authors was that an end\r\n entity certificate is not valid for use in verifying a signature\r\nShirey Informational [Page 120]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n on an X.509 certificate or X.509 CRL. Thus, it would have been\r\n better for the X.509 definition to have said \"only for purposes\r\n other than signing certificates\".\r\n Usage: Despite the problems in the X.509 definition, the term\r\n itself is useful in describing applications of asymmetric\r\n cryptography. The way the term is used in X.509 implies that it\r\n was meant to be defined, as we have done here, relative to roles\r\n that an entity (which is associated with an OSI end system) is\r\n playing or is permitted to play in applications of asymmetric\r\n cryptography other than the PKI that supports applications.\r\n Tutorial: Whether a subject can play both CA and non-CA roles,\r\n with either the same or different certificates, is a matter of\r\n policy. (See: CPS.) A v3 X.509 public-key certificate may have a\r\n \"basicConstraints\" extension containing a \"cA\" value that\r\n specifically \"indicates whether or not the public key may be used\r\n to verify certificate signatures\". (See: certificate profile.)\r\n $ end system\r\n (N) /OSIRM/ A computer that implements all seven layers of the\r\n OSIRM and may attach to a subnetwork. Usage: In the IPS context,\r\n an end system is called a \"host\".\r\n $ end-to-end encryption\r\n (I) Continuous protection of data that flows between two points in\r\n a network, effected by encrypting data when it leaves its source,\r\n keeping it encrypted while it passes through any intermediate\r\n computers (such as routers), and decrypting it only when it\r\n arrives at the intended final destination. (See: wiretapping.\r\n Compare: link encryption.)\r\n Examples: A few are BLACKER, CANEWARE, IPLI, IPsec, PLI, SDNS,\r\n SILS, SSH, SSL, TLS.\r\n Tutorial: When two points are separated by multiple communication\r\n links that are connected by one or more intermediate relays, end-https://www.ietf.org/rfc/rfc4949.txt\r\nPage 144 of 436\n\nto-end encryption enables the source and destination systems to\r\n protect their communications without depending on the intermediate\r\n systems to provide the protection.\r\n $ end user\r\n 1. (I) /information system/ A system entity, usually a human\r\n individual, that makes use of system resources, primarily for\r\n application purposes as opposed to system management purposes.\r\n 2. (D) /PKI/ Synonym for \"end entity\".\r\nShirey Informational [Page 121]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Definition: IDOCs SHOULD NOT use \"end user\" as a\r\n synonym for \"end entity\", because that would mix concepts in a\r\n potentially misleading way.\r\n $ endorsed-for-unclassified cryptographic item (EUCI)\r\n (O) /U.S. Government/ \"Unclassified cryptographic equipment that\r\n embodies a U.S. Government classified cryptographic logic and is\r\n endorsed by NSA for the protection of national security\r\n information.\" [C4009] (Compare: CCI, type 2 product.)\r\n $ entity\r\n See: system entity.\r\n $ entrapment\r\n (I) \"The deliberate planting of apparent flaws in a system for the\r\n purpose of detecting attempted penetrations or confusing an\r\n intruder about which flaws to exploit.\" [FP039] (See: honey pot.)\r\n $ entropy\r\n 1. (I) An information-theoretic measure (usually stated as a\r\n number of bits) of the amount of uncertainty that an attacker\r\n faces to determine the value of a secret. [SP63] (See: strength.)\r\n Example: If a password is said to contain at least 20 bits of\r\n entropy, that means that it must be as hard to find the password\r\n as to guess a 20-bit random number.\r\n 2. (I) An information-theoretic measure (usually stated as a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 145 of 436\n\nnumber of bits) of the amount of information in a message; i.e.,\r\n the minimum number of bits needed to encode all possible meanings\r\n of that message. [Schn] (See: uncertainty.)\r\n $ ephemeral\r\n (I) /adjective/ Refers to a cryptographic key or other\r\n cryptographic parameter or data object that is short-lived,\r\n temporary, or used one time. (See: session key. Compare: static.)\r\n $ erase\r\n 1. (I) Delete stored data. (See: sanitize, zeroize.)\r\n 2. (O) /U.S. Government/ Delete magnetically stored data in such a\r\n way that the data cannot be recovered by ordinary means, but might\r\n be recoverable by laboratory methods. [C4009] (Compare: /U.S.\r\n Government/ purge.)\r\n $ error detection code\r\n (I) A checksum designed to detect, but not correct, accidental\r\n (i.e., unintentional) changes in data.\r\nShirey Informational [Page 122]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Escrowed Encryption Standard (EES)\r\n (N) A U.S. Government standard [FP185] that specifies how to use a\r\n symmetric encryption algorithm (SKIPJACK) and create a Law\r\n Enforcement Access Field (LEAF) for implementing part of a key\r\n escrow system that enables decryption of telecommunications when\r\n interception is lawfully authorized.\r\n Tutorial: Both SKIPJACK and the LEAF are intended for use in\r\n equipment used to encrypt and decrypt sensitive, unclassified,\r\n telecommunications data.\r\n $ ESP\r\n (I) See: Encapsulating Security Payload.\r\n $ Estelle\r\n (N) A language (ISO 9074-1989) for formal specification of\r\n computer network protocols.\r\n $ ETSI\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 146 of 436\n\n(N) See: European Telecommunication Standards Institute.\r\n $ EUCI\r\n (O) See: endorsed-for-unclassified cryptographic item.\r\n $ European Telecommunication Standards Institute (ETSI)\r\n (N) An independent, non-profit organization, based in France, that\r\n is officially recognized by the European Commission and\r\n responsible for standardization of information and communication\r\n technologies within Europe.\r\n Tutorial: ETSI maintains the standards for a number of security\r\n algorithms, including encryption algorithms for mobile telephone\r\n systems in Europe.\r\n $ evaluated system\r\n (I) A system that has been evaluated against security criteria\r\n (for example, against the TCSEC or against a profile based on the\r\n Common Criteria).\r\n $ evaluation\r\n (I) Assessment of an information system against defined security\r\n criteria (for example, against the TCSEC or against a profile\r\n based on the Common Criteria). (Compare: certification.)\r\n $ evaluation assurance level (EAL)\r\n (N) A predefined package of assurance components that represents a\r\n point on the Common Criteria's scale for rating confidence in the\r\n security of information technology products and systems.\r\nShirey Informational [Page 123]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: The Common Criteria defines a scale of seven,\r\n hierarchically ordered EALs for rating a TOE. From highest to\r\n lowest, they are as follows:\r\n - EAL7. Formally verified design and tested.\r\n - EAL6. Semiformally verified design and tested.\r\n - EAL5. Semiformally designed and tested.\r\n - EAL4. Methodically designed, tested, and reviewed.\r\n - EAL3. Methodically tested and checked.\r\n - EAL2. Structurally tested.\r\n - EAL1. Functionally tested.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 147 of 436\n\nAn EAL is a consistent, baseline set of requirements. The increase\r\n in assurance from EAL to EAL is accomplished by substituting\r\n higher assurance components (i.e., criteria of increasing rigor,\r\n scope, or depth) from seven assurance classes: (a) configuration\r\n management, (b) delivery and operation, (c) development, (d)\r\n guidance documents, (e) lifecycle support, (f) tests, and (g)\r\n vulnerability assessment.\r\n The EALs were developed with the goal of preserving concepts of\r\n assurance that were adopted from earlier criteria, so that results\r\n of previous evaluations would remain relevant. For example, EALs\r\n levels 2-7 are generally equivalent to the assurance portions of\r\n the TCSEC C2-A1 scale. However, this equivalency should be used\r\n with caution. The levels do not derive assurance in the same\r\n manner, and exact mappings do not exist.\r\n $ expire\r\n (I) /credential/ Cease to be valid (i.e., change from being valid\r\n to being invalid) because its assigned lifetime has been exceeded.\r\n (See: certificate expiration.)\r\n $ exposure\r\n (I) A type of threat action whereby sensitive data is directly\r\n released to an unauthorized entity. (See: unauthorized\r\n disclosure.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Deliberate Exposure\": Intentional release of sensitive data to\r\n an unauthorized entity.\r\n - \"Scavenging\": Searching through data residue in a system to\r\n gain unauthorized knowledge of sensitive data.\r\n - \"Human error\": /exposure/ Human action or inaction that\r\n unintentionally results in an entity gaining unauthorized\r\n knowledge of sensitive data. (Compare: corruption,\r\n incapacitation.)\r\n - \"Hardware or software error\": /exposure/ System failure that\r\n unintentionally results in an entity gaining unauthorized\r\nShirey Informational [Page 124]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n knowledge of sensitive data. (Compare: corruption,\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 148 of 436\n\nincapacitation.)\r\n $ Extended Security Option\r\n (I) See: secondary definition under \"IPSO\".\r\n $ Extensible Authentication Protocol (EAP)\r\n (I) An extension framework for PPP that supports multiple,\r\n optional authentication mechanisms, including cleartext passwords,\r\n challenge-response, and arbitrary dialog sequences. [R3748]\r\n (Compare: GSS-API, SASL.)\r\n Tutorial: EAP typically runs directly over IPS data link protocols\r\n or OSIRM Layer 2 protocols, i.e., without requiring IP.\r\n Originally, EAP was developed for use in PPP, by a host or router\r\n that connects to a network server via switched circuits or dial-up\r\n lines. Today, EAP's domain of applicability includes other areas\r\n of network access control; it is used in wired and wireless LANs\r\n with IEEE 802.1X, and in IPsec with IKEv2. EAP is conceptually\r\n related to other authentication mechanism frameworks, such as SASL\r\n and GSS-API.\r\n $ Extensible Markup Language (XML)\r\n (N) A version of Standard Generalized Markup Language (ISO 8879)\r\n that separately represents a document's content and its structure.\r\n XML was designed by W3C for use on the World Wide Web.\r\n $ extension\r\n (I) /protocol/ A data item or a mechanism that is defined in a\r\n protocol to extend the protocol's basic or original functionality.\r\n Tutorial: Many protocols have extension mechanisms, and the use of\r\n these extension is usually optional. IP and X.509 are two examples\r\n of protocols that have optional extensions. In IP version 4,\r\n extensions are called \"options\", and some of the options have\r\n security purposes (see: IPSO).\r\n In X.509, certificate and CRL formats can be extended to provide\r\n methods for associating additional attributes with subjects and\r\n public keys and for managing a certification hierarchy:\r\n - A \"certificate extension\": X.509 defines standard extensions\r\n that may be included in v3 certificates to provide additional\r\n key and security policy information, subject and issuer\r\n attributes, and certification path constraints.\r\n - A \"CRL extension\": X.509 defines extensions that may be\r\n included in v2 CRLs to provide additional issuer key and name\r\n information, revocation reasons and constraints, and\r\n information about distribution points and delta CRLs.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 149 of 436\n\nShirey Informational [Page 125]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - A \"private extension\": Additional extensions, each named by an\r\n OID, can be locally defined as needed by applications or\r\n communities. (See: Authority Information Access extension, SET\r\n private extensions.)\r\n $ external controls\r\n (I) /COMPUSEC/ Refers to administrative security, personnel\r\n security, and physical security. (Compare: internal controls.)\r\n $ extranet\r\n (I) A computer network that an organization uses for application\r\n data traffic between the organization and its business partners.\r\n (Compare: intranet.)\r\n Tutorial: An extranet can be implemented securely, either on the\r\n Internet or using Internet technology, by constructing the\r\n extranet as a VPN.\r\n $ extraction resistance\r\n (O) Ability of cryptographic equipment to resist efforts to\r\n extract keying material directly from the equipment (as opposed to\r\n gaining knowledge of keying material by cryptanalysis). [C4009]\r\n $ extrusion detection\r\n (I) Monitoring for unauthorized transfers of sensitive information\r\n and other communications that originate inside a system's security\r\n perimeter and are directed toward the outside; i.e., roughly the\r\n opposite of \"intrusion detection\".\r\n $ fail-safe\r\n 1. (I) Synonym for \"fail-secure\".\r\n 2. (I) A mode of termination of system functions that prevents\r\n damage to specified system resources and system entities (i.e.,\r\n specified data, property, and life) when a failure occurs or is\r\n detected in the system (but the failure still might cause a\r\n security compromise). (See: failure control.)\r\n Tutorial: Definitions 1 and 2 are opposing design alternatives.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 150 of 436\n\nTherefore, IDOCs SHOULD NOT use this term without providing a\r\n definition for it. If definition 1 is intended, IDOCs can avoid\r\n ambiguity by using \"fail-secure\" instead.\r\n $ fail-secure\r\n (I) A mode of termination of system functions that prevents loss\r\n of secure state when a failure occurs or is detected in the system\r\n (but the failure still might cause damage to some system resource\r\n or system entity). (See: failure control. Compare: fail-safe.)\r\nShirey Informational [Page 126]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ fail-soft\r\n (I) Selective termination of affected, non-essential system\r\n functions when a failure occurs or is detected in the system.\r\n (See: failure control.)\r\n $ failure control\r\n (I) A methodology used to provide fail-safe, fail-secure or fail-\r\n soft termination and recovery of system functions. [FP039]\r\n $ fairness\r\n (I) A property of an access protocol for a system resource whereby\r\n the resource is made equitably or impartially available to all\r\n eligible users. (RFC 3753)\r\n Tutorial: Fairness can be used to defend against some types of\r\n denial-of-service attacks on a system connected to a network.\r\n However, this technique assumes that the system can properly\r\n receive and process inputs from the network. Therefore, the\r\n technique can mitigate flooding but is ineffective against\r\n jamming.\r\n $ falsification\r\n (I) A type of threat action whereby false data deceives an\r\n authorized entity. (See: active wiretapping, deception.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Substitution\": Altering or replacing valid data with false\r\n data that serves to deceive an authorized entity.\r\n - \"Insertion\": Introducing false data that serves to deceive an\r\n authorized entity.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 151 of 436\n\n$ fault tree\r\n (I) A branching, hierarchical data structure that is used to\r\n represent events and to determine the various combinations of\r\n component failures and human acts that could result in a specified\r\n undesirable system event. (See: attack tree, flaw hypothesis\r\n methodology.)\r\n Tutorial: \"Fault-tree analysis\" is a technique in which an\r\n undesired state of a system is specified and the system is studied\r\n in the context of its environment and operation to find all\r\n credible ways in which the event could occur. The specified fault\r\n event is represented as the root of the tree. The remainder of the\r\n tree represents AND or OR combinations of subevents, and\r\n sequential combinations of subevents, that could cause the root\r\n event to occur. The main purpose of a fault-tree analysis is to\r\n calculate the probability of the root event, using statistics or\r\n other analytical methods and incorporating actual or predicted\r\nShirey Informational [Page 127]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n quantitative reliability and maintainability data. When the root\r\n event is a security violation, and some of the subevents are\r\n deliberate acts intended to achieve the root event, then the fault\r\n tree is an attack tree.\r\n $ FEAL\r\n (O) A family of symmetric block ciphers that was developed in\r\n Japan; uses a 64-bit block, keys of either 64 or 128 bits, and a\r\n variable number of rounds; and has been successfully attacked by\r\n cryptanalysts. [Schn]\r\n $ Federal Information Processing Standards (FIPS)\r\n (N) The Federal Information Processing Standards Publication (FIPS\r\n PUB) series issued by NIST under the provisions of Section 111(d)\r\n of the Federal Property and Administrative Services Act of 1949 as\r\n amended by the Computer Security Act of 1987 (Public Law 100-235)\r\n as technical guidelines for U.S. Government procurements of\r\n information processing system equipment and services. (See:\r\n \"[FPxxx]\" items in Section 7, Informative References.)\r\n $ Federal Public-key Infrastructure (FPKI)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 152 of 436\n\n(O) A PKI being planned to establish facilities, specifications,\r\n and policies needed by the U.S. Government to use public-key\r\n certificates in systems involving unclassified but sensitive\r\n applications and interactions between Federal agencies as well as\r\n with entities of state and local governments, the business\r\n community, and the public. [FPKI]\r\n $ Federal Standard 1027\r\n (N) An U.S. Government document defining emanation, anti-tamper,\r\n security fault analysis, and manual key management criteria for\r\n DES encryption devices, primary for OSIRM Layer 2. Was renamed\r\n \"FIPS PUB 140\" when responsibility for protecting unclassified,\r\n sensitive information was transferred from NSA to NIST, and has\r\n since been superseded by newer versions of that standard [FP140].\r\n $ File Transfer Protocol (FTP)\r\n (I) A TCP-based, Application-Layer, Internet Standard protocol\r\n (RFC 959) for moving data files from one computer to another.\r\n $ fill device\r\n (N) /COMSEC/ A device used to transfer or store keying material in\r\n electronic form or to insert keying material into cryptographic\r\n equipment.\r\n $ filter\r\n 1. (I) /noun/ Synonym for \"guard\". (Compare: content filter,\r\n filtering router.)\r\nShirey Informational [Page 128]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /verb/ To process a flow of data and selectively block\r\n passage or permit passage of individual data items according to a\r\n security policy.\r\n $ filtering router\r\n (I) An internetwork router that selectively prevents the passage\r\n of data packets according to a security policy. (See: guard.)\r\n Tutorial: A router usually has two or more physical connections to\r\n networks or other systems; and when the router receives a packet\r\n on one of those connections, it forwards the packet on a second\r\n connection. A filtering router does the same; but it first\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 153 of 436\n\ndecides, according to some security policy, whether the packet\r\n should be forwarded at all. The policy is implemented by rules\r\n (packet filters) loaded into the router. The rules mostly involve\r\n values of data packet control fields (especially IP source and\r\n destination addresses and TCP port numbers) [R2179]. A filtering\r\n router may be used alone as a simple firewall or be used as a\r\n component of a more complex firewall.\r\n $ financial institution\r\n (N) \"An establishment responsible for facilitating customer-\r\n initiated transactions or transmission of funds for the extension\r\n of credit or the custody, loan, exchange, or issuance of money.\"\r\n [SET2]\r\n $ fingerprint\r\n 1. (I) A pattern of curves formed by the ridges on a fingertip.\r\n (See: biometric authentication. Compare: thumbprint.)\r\n 2. (D) /PGP/ A hash result (\"key fingerprint\") used to\r\n authenticate a public key or other data. [PGP]\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 2, and SHOULD NOT use this term as a synonym for \"hash\r\n result\" of *any* kind. Either use would mix concepts in a\r\n potentially misleading way.\r\n $ FIPS\r\n (N) See: Federal Information Processing Standards.\r\n $ FIPS PUB 140\r\n (N) The U.S. Government standard [FP140] for security requirements\r\n to be met by a cryptographic module when the module is used to\r\n protect unclassified information in computer and communication\r\n systems. (See: Common Criteria, FIPS, Federal Standard 1027.)\r\nShirey Informational [Page 129]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: The standard specifies four increasing levels (from\r\n \"Level 1\" to \"Level 4\") of requirements to cover a wide range of\r\n potential applications and environments. The requirements address\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 154 of 436\n\nbasic design and documentation, module interfaces, authorized\r\n roles and services, physical security, software security,\r\n operating system security, key management, cryptographic\r\n algorithms, electromagnetic interference and electromagnetic\r\n compatibility (EMI/EMC), and self-testing. NIST and the Canadian\r\n Communication Security Establishment jointly certify modules.\r\n $ FIREFLY\r\n (O) /U.S. Government/ \"Key management protocol based on public-key\r\n cryptography.\" [C4009]\r\n $ firewall\r\n 1. (I) An internetwork gateway that restricts data communication\r\n traffic to and from one of the connected networks (the one said to\r\n be \"inside\" the firewall) and thus protects that network's system\r\n resources against threats from the other network (the one that is\r\n said to be \"outside\" the firewall). (See: guard, security\r\n gateway.)\r\n 2. (O) A device or system that controls the flow of traffic\r\n between networks using differing security postures. [SP41]\r\n Tutorial: A firewall typically protects a smaller, secure network\r\n (such as a corporate LAN, or even just one host) from a larger\r\n network (such as the Internet). The firewall is installed at the\r\n point where the networks connect, and the firewall applies policy\r\n rules to control traffic that flows in and out of the protected\r\n network.\r\n A firewall is not always a single computer. For example, a\r\n firewall may consist of a pair of filtering routers and one or\r\n more proxy servers running on one or more bastion hosts, all\r\n connected to a small, dedicated LAN (see: buffer zone) between the\r\n two routers. The external router blocks attacks that use IP to\r\n break security (IP address spoofing, source routing, packet\r\n fragments), while proxy servers block attacks that would exploit a\r\n vulnerability in a higher-layer protocol or service. The internal\r\n router blocks traffic from leaving the protected network except\r\n through the proxy servers. The difficult part is defining criteria\r\n by which packets are denied passage through the firewall, because\r\n a firewall not only needs to keep unauthorized traffic (i.e.,\r\n intruders) out, but usually also needs to let authorized traffic\r\n pass both in and out.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 155 of 436\n\nShirey Informational [Page 130]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ firmware\r\n (I) Computer programs and data stored in hardware -- typically in\r\n read-only memory (ROM) or programmable read-only memory (PROM) --\r\n such that the programs and data cannot be dynamically written or\r\n modified during execution of the programs. (See: hardware,\r\n software.)\r\n $ FIRST\r\n (N) See: Forum of Incident Response and Security Teams.\r\n $ flaw\r\n 1. (I) An error in the design, implementation, or operation of an\r\n information system. A flaw may result in a vulnerability.\r\n (Compare: vulnerability.)\r\n 2. (D) \"An error of commission, omission, or oversight in a system\r\n that allows protection mechanisms to be bypassed.\" [NCSSG]\r\n (Compare: vulnerability. See: brain-damaged.)\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 2; not every flaw is a vulnerability.\r\n $ flaw hypothesis methodology\r\n (I) An evaluation or attack technique in which specifications and\r\n documentation for a system are analyzed to hypothesize flaws in\r\n the system. The list of hypothetical flaws is prioritized on the\r\n basis of the estimated probability that a flaw exists and,\r\n assuming it does, on the ease of exploiting it and the extent of\r\n control or compromise it would provide. The prioritized list is\r\n used to direct a penetration test or attack against the system.\r\n [NCS04] (See: fault tree, flaw.)\r\n $ flooding\r\n 1. (I) An attack that attempts to cause a failure in a system by\r\n providing more input than the system can process properly. (See:\r\n denial of service, fairness. Compare: jamming.)\r\n Tutorial: Flooding uses \"overload\" as a type of \"obstruction\"\r\n intended to cause \"disruption\".\r\n 2. (I) The process of delivering data or control messages to every\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 156 of 436\n\nnode of a network. (RFC 3753)\r\n $ flow analysis\r\n (I) An analysis performed on a nonprocedural, formal, system\r\n specification that locates potential flows of information between\r\n system variables. By assigning security levels to the variables,\r\n the analysis can find some types of covert channels. [Huff]\r\nShirey Informational [Page 131]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ flow control\r\n 1. (I) /data security/ A procedure or technique to ensure that\r\n information transfers within a system are not made from one\r\n security level to another security level, and especially not from\r\n a higher level to a lower level. [Denns] (See: covert channel,\r\n confinement property, information flow policy, simple security\r\n property.)\r\n 2. (O) /data security/ \"A concept requiring that information\r\n transfers within a system be controlled so that information in\r\n certain types of objects cannot, via any channel within the\r\n system, flow to certain other types of objects.\" [NCSSG]\r\n $ For Official Use Only (FOUO)\r\n (O) /U.S. DoD/ A U.S. Government designation for information that\r\n has not been given a security classification pursuant to the\r\n criteria of an Executive Order dealing with national security, but\r\n which may be withheld from the public because disclosure would\r\n cause a foreseeable harm to an interest protected by one of the\r\n exemptions stated in the Freedom of Information Act (Section 552\r\n of title 5, United States Code). (See: security label, security\r\n marking. Compare: classified.)\r\n $ formal\r\n (I) Expressed in a restricted syntax language with defined\r\n semantics based on well-established mathematical concepts. [CCIB]\r\n (Compare: informal, semiformal.)\r\n $ formal access approval\r\n (O) /U.S. Government/ Documented approval by a data owner to allow\r\n access to a particular category of information in a system. (See:\r\n category.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 157 of 436\n\n$ Formal Development Methodology\r\n (O) See: Ina Jo.\r\n $ formal model\r\n (I) A security model that is formal. Example: Bell-LaPadula model.\r\n [Land] (See: formal, security model.)\r\n $ formal proof\r\n (I) \"A complete and convincing mathematical argument, presenting\r\n the full logical justification for each step in the proof, for the\r\n truth of a theorem or set of theorems.\" [NCSSG]\r\n $ formal specification\r\n (I) A precise description of the (intended) behavior of a system,\r\n usually written in a mathematical language, sometimes for the\r\nShirey Informational [Page 132]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n purpose of supporting formal verification through a correctness\r\n proof. [Huff] (See: Affirm, Gypsy, HDM, Ina Jo.) (See: formal.)\r\n Tutorial: A formal specification can be written at any level of\r\n detail but is usually a top-level specification.\r\n $ formal top-level specification\r\n (I) \"A top-level specification that is written in a formal\r\n mathematical language to allow theorems showing the correspondence\r\n of the system specification to its formal requirements to be\r\n hypothesized and formally proven.\" [NCS04] (See: formal\r\n specification.)\r\n $ formulary\r\n (I) A technique for enabling a decision to grant or deny access to\r\n be made dynamically at the time the access is attempted, rather\r\n than earlier when an access control list or ticket is created.\r\n $ FORTEZZA(trademark)\r\n (O) A registered trademark of NSA, used for a family of\r\n interoperable security products that implement a NIST/NSA-approved\r\n suite of cryptographic algorithms for digital signature, hash,\r\n encryption, and key exchange. The products include a PC card\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 158 of 436\n\n(which contains a CAPSTONE chip), and compatible serial port\r\n modems, server boards, and software implementations.\r\n $ Forum of Incident Response and Security Teams (FIRST)\r\n (N) An international consortium of CSIRTs (e.g., CIAC) that work\r\n together to handle computer security incidents and promote\r\n preventive activities. (See: CSIRT, security incident.)\r\n Tutorial: FIRST was founded in 1990 and, as of July 2004, had more\r\n than 100 members spanning the globe. Its mission includes:\r\n - Provide members with technical information, tools, methods,\r\n assistance, and guidance.\r\n - Coordinate proactive liaison activities and analytical support.\r\n - Encourage development of quality products and services.\r\n - Improve national and international information security for\r\n governments, private industry, academia, and the individual.\r\n - Enhance the image and status of the CSIRT community.\r\n $ forward secrecy\r\n (I) See: perfect forward secrecy.\r\n $ FOUO\r\n (O) See: For Official Use Only.\r\nShirey Informational [Page 133]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ FPKI\r\n (O) See: Federal Public-Key Infrastructure.\r\n $ fraggle attack\r\n (D) /slang/ A synonym for \"smurf attack\".\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term.\r\n Derivation: The Fraggles are a fictional race of small humanoids\r\n (represented as hand puppets in a children's television series,\r\n \"Fraggle Rock\") that live underground.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 159 of 436\n\n$ frequency hopping\r\n (N) Repeated switching of frequencies during radio transmission\r\n according to a specified algorithm. [C4009] (See: spread\r\n spectrum.)\r\n Tutorial: Frequency hopping is a TRANSEC technique to minimize the\r\n potential for unauthorized interception or jamming.\r\n $ fresh\r\n (I) Recently generated; not replayed from some earlier interaction\r\n of the protocol.\r\n Usage: Describes data contained in a PDU that is received and\r\n processed for the first time. (See: liveness, nonce, replay\r\n attack.)\r\n $ FTP\r\n (I) See: File Transfer Protocol.\r\n $ gateway\r\n (I) An intermediate system (interface, relay) that attaches to two\r\n (or more) computer networks that have similar functions but\r\n dissimilar implementations and that enables either one-way or two-\r\n way communication between the networks. (See: bridge, firewall,\r\n guard, internetwork, proxy server, router, and subnetwork.)\r\n Tutorial: The networks may differ in any of several aspects,\r\n including protocols and security mechanisms. When two computer\r\n networks differ in the protocol by which they offer service to\r\n hosts, a gateway may translate one protocol into the other or\r\n otherwise facilitate interoperation of hosts (see: Internet\r\n Protocol). In theory, gateways between computer networks are\r\n conceivable at any OSIRM layer. In practice, they usually operate\r\nShirey Informational [Page 134]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n at OSIRM Layer 2 (see: bridge), 3 (see: router), or 7 (see: proxy\r\n server).\r\n $ GCA\r\n (O) See: geopolitical certificate authority.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 160 of 436\n\n$ GDOI\r\n (O) See: Group Domain of Interpretation.\r\n $ GeldKarte\r\n (O) A smartcard-based, electronic money system that is maintained\r\n by the German banking industry, incorporates cryptography, and can\r\n be used to make payments via the Internet. (See: IOTP.)\r\n $ GeneralizedTime\r\n (N) The ASN.1 data type \"GeneralizedTime\" (ISO 8601) contains a\r\n calendar date (YYYYMMDD) and a time of day, which is either (a)\r\n the local time, (b) the Coordinated Universal Time, or (c) both\r\n the local time and an offset that enables Coordinated Universal\r\n Time to be calculated. (See: Coordinated Universal Time. Compare:\r\n UTCTime.)\r\n $ Generic Security Service Application Program Interface (GSS-API)\r\n (I) An Internet Standard protocol [R2743] that specifies calling\r\n conventions by which an application (typically another\r\n communication protocol) can obtain authentication, integrity, and\r\n confidentiality security services independently of the underlying\r\n security mechanisms and technologies, thus enabling the\r\n application source code to be ported to different environments.\r\n (Compare: EAP, SASL.)\r\n Tutorial: \"A GSS-API caller accepts tokens provided to it by its\r\n local GSS-API implementation and transfers the tokens to a peer on\r\n a remote system; that peer passes the received tokens to its local\r\n GSS-API implementation for processing. The security services\r\n available through GSS-API in this fashion are implementable (and\r\n have been implemented) over a range of underlying mechanisms based\r\n on [symmetric] and [asymmetric cryptography].\" [R2743]\r\n $ geopolitical certificate authority (GCA)\r\n (O) /SET/ In a SET certification hierarchy, an optional level that\r\n is certified by a BCA and that may certify cardholder CAs,\r\n merchant CAs, and payment gateway CAs. Using GCAs enables a brand\r\n to distribute responsibility for managing certificates to\r\n geographic or political regions, so that brand policies can vary\r\n between regions as needed.\r\nShirey Informational [Page 135]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 161 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ GIG\r\n (O) See: Global Information Grid.\r\n $ Global Information Grid (GIG)\r\n (O) /U.S. DoD/ The GIG is \"a globally interconnected, end-to-end\r\n set of information capabilities, associated processes and\r\n personnel for collecting, processing, storing, disseminating, and\r\n managing information on demand to war fighters, policy makers, and\r\n support personnel.\" [IATF] Usage: Formerly referred to as the DII.\r\n $ good engineering practice(s)\r\n (N) A term used to specify or characterize design, implementation,\r\n installation, or operating practices for an information system,\r\n when a more explicit specification is not possible. Generally\r\n understood to refer to the state of the engineering art for\r\n commercial systems that have problems and solutions equivalent to\r\n the system in question.\r\n $ granularity\r\n 1. (N) /access control/ Relative fineness to which an access\r\n control mechanism can be adjusted.\r\n 2. (N) /data security/ \"The size of the smallest protectable unit\r\n of information\" in a trusted system. [Huff]\r\n $ Green Book\r\n (D) /slang/ Synonym for \"Defense Password Management Guideline\"\r\n [CSC2].\r\n Deprecated Term: Except as an explanatory appositive, IDOCs SHOULD\r\n NOT use this term, regardless of the associated definition.\r\n Instead, use the full proper name of the document or, in\r\n subsequent references, a conventional abbreviation. (See: Rainbow\r\n Series.)\r\n Deprecated Usage: To improve international comprehensibility of\r\n Internet Standards and the Internet Standards Process, IDOCs\r\n SHOULD NOT use \"cute\" synonyms. No matter how clearly understood\r\n or popular a nickname may be in one community, it is likely to\r\n cause confusion or offense in others. For example, several other\r\n information system standards also are called \"the Green Book\"; the\r\n following are some examples:\r\n - Each volume of 1992 ITU-T (known at that time as CCITT)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 162 of 436\n\nstandards.\r\n - \"PostScript Language Program Design\", Adobe Systems, Addison-\r\n Wesley, 1988.\r\n - IEEE 1003.1 POSIX Operating Systems Interface.\r\nShirey Informational [Page 136]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - \"Smalltalk-80: Bits of History, Words of Advice\", Glenn\r\n Krasner, Addison-Wesley, 1983.\r\n - \"X/Open Compatibility Guide\".\r\n - A particular CD-ROM format developed by Phillips.\r\n $ Group Domain of Interpretation (GDOI)\r\n (I) An ISAKMP/IKE domain of interpretation for group key\r\n management; i.e., a phase 2 protocol in ISAKMP. [R3547] (See:\r\n secure multicast.)\r\n Tutorial: In this group key management model that extends the\r\n ISAKMP standard, the protocol is run between a group member and a\r\n \"group controller/key server\", which establishes security\r\n associations [R4301] among authorized group members. The GDOI\r\n protocol is itself protected by an ISAKMP phase 1 association.\r\n For example, multicast applications may use ESP to protect their\r\n data traffic. GDOI carries the needed security association\r\n parameters for ESP. In this way, GDOI supports multicast ESP with\r\n group authentication of ESP packets using a shared, group key.\r\n $ group identity\r\n (I) See: secondary definition under \"identity\".\r\n $ group security association\r\n (I) \"A bundling of [security associations] (SAs) that together\r\n define how a group communicates securely. The [group SA] may\r\n include a registration protocol SA, a rekey protocol SA, and one\r\n or more data security protocol SAs.\" [R3740]\r\n $ GSS-API\r\n (I) See: Generic Security Service Application Program Interface.\r\n $ guard\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 163 of 436\n\n(I) A computer system that (a) acts as gateway between two\r\n information systems operating under different security policies\r\n and (b) is trusted to mediate information data transfers between\r\n the two. (See: controlled interface, cross-domain solution,\r\n domain, filter. Compare: firewall.)\r\n Usage: Frequently understood to mean that one system is operating\r\n at a higher security level than the other, and that the gateway's\r\n purpose is to prevent unauthorized disclosure of data from the\r\n higher system to the lower. However, the purpose might also be to\r\n protect the data integrity, availability, or general system\r\n integrity of one system from threats posed by connecting to the\r\n other system. The mediation may be entirely automated or may\r\n involve \"reliable human review\".\r\nShirey Informational [Page 137]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ guest login\r\n (I) See: anonymous login.\r\n $ GULS\r\n (I) Generic Upper Layer Security service element (ISO 11586), a\r\n five-part standard for the exchange of security information and\r\n security-transformation functions that protect confidentiality and\r\n integrity of application data.\r\n $ Gypsy verification environment\r\n (O) A methodology, language, and integrated set of software tools\r\n developed at the University of Texas for specifying, coding, and\r\n verifying software to produce correct and reliable programs.\r\n [Cheh]\r\n $ H field\r\n (D) See: Deprecated Usage under \"Handling Restrictions field\".\r\n $ hack\r\n 1a. (I) /verb/ To work on something, especially to program a\r\n computer. (See: hacker.)\r\n 1b. (I) /verb/ To do some kind of mischief, especially to play a\r\n prank on, or penetrate, a system. (See: hacker, cracker.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 164 of 436\n\n2. (I) /noun/ An item of completed work, or a solution for a\r\n problem, that is non-generalizable, i.e., is very specific to the\r\n application area or problem being solved.\r\n Tutorial: Often, the application area or problem involves computer\r\n programming or other use of a computer. Characterizing something\r\n as a hack can be a compliment, such as when the solution is\r\n minimal and elegant; or it can be derogatory, such as when the\r\n solution fixes the problem but leaves the system in an\r\n unmaintainable state.\r\n See [Raym] for several other meanings of this term and also\r\n definitions of several derivative terms.\r\n $ hacker\r\n 1. (I) Someone with a strong interest in computers, who enjoys\r\n learning about them, programming them, and experimenting and\r\n otherwise working with them. (See: hack. Compare: adversary,\r\n cracker, intruder.)\r\n Usage: This first definition is the original meaning of the term\r\n (circa 1960); it then had a neutral or positive connotation of\r\n \"someone who figures things out and makes something cool happen\".\r\nShirey Informational [Page 138]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (O) \"An individual who spends an inordinate amount of time\r\n working on computer systems for other than professional purposes.\"\r\n [NCSSG]\r\n 3. (D) Synonym for \"cracker\".\r\n Deprecated Usage: Today, the term is frequently (mis)used\r\n (especially by journalists) with definition 3.\r\n $ handle\r\n 1. (I) /verb/ Perform processing operations on data, such as\r\n receive and transmit, collect and disseminate, create and delete,\r\n store and retrieve, read and write, and compare. (See: access.)\r\n 2. (I) /noun/ An online pseudonym, particularly one used by a\r\n cracker; derived from citizens' band radio culture.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 165 of 436\n\n$ handling restriction\r\n (I) A type of access control other than (a) the rule-based\r\n protections of mandatory access control and (b) the identity-based\r\n protections of discretionary access control; usually involves\r\n administrative security.\r\n $ Handling Restrictions field\r\n (I) A 16-bit field that specifies a control and release marking in\r\n the security option (option type 130) of IP's datagram header\r\n format. The valid field values are alphanumeric digraphs assigned\r\n by the U.S. Government, as specified in RFC 791.\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use the abbreviation \"H\r\n field\" because it is potentially ambiguous. Instead, use \"Handling\r\n Restrictions field\".\r\n $ handshake\r\n (I) Protocol dialogue between two systems for identifying and\r\n authenticating themselves to each other, or for synchronizing\r\n their operations with each other.\r\n $ Handshake Protocol\r\n (I) /TLS/ The TLS Handshake Protocol consists of three parts\r\n (i.e., subprotocols) that enable peer entities to agree upon\r\n security parameters for the record layer, authenticate themselves\r\n to each other, instantiate negotiated security parameters, and\r\n report error conditions to each other. [R4346]\r\nShirey Informational [Page 139]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ harden\r\n (I) To protect a system by configuring it to operate in a way that\r\n eliminates or mitigates known vulnerabilities. Example: [RSCG].\r\n (See: default account.)\r\n $ hardware\r\n (I) The material physical components of an information system.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 166 of 436\n\n(See: firmware, software.)\r\n $ hardware error\r\n (I) /threat action/ See: secondary definitions under \"corruption\",\r\n \"exposure\", and \"incapacitation\".\r\n $ hardware token\r\n See: token.\r\n $ hash code\r\n (D) Synonym for \"hash result\" or \"hash function\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it mixes concepts\r\n in a potentially misleading way. A hash result is not a \"code\",\r\n and a hash function does not \"encode\" in any sense defined by this\r\n glossary. (See: hash value, message digest.)\r\n $ hash function\r\n 1. (I) A function H that maps an arbitrary, variable-length bit\r\n string, s, into a fixed-length string, h = H(s) (called the \"hash\r\n result\"). For most computing applications, it is desirable that\r\n given a string s with H(s) = h, any change to s that creates a\r\n different string s' will result in an unpredictable hash result\r\n H(s') that is, with high probability, not equal to H(s).\r\n 2. (O) \"A (mathematical) function which maps values from a large\r\n (possibly very large) domain into a smaller range. A 'good' hash\r\n function is such that the results of applying the function to a\r\n (large) set of values in the domain will be evenly distributed\r\n (and apparently at random) over the range.\" [X509]\r\n Tutorial: A hash function operates on variable-length input (e.g.,\r\n a message or a file) and outputs a fixed-length output, which\r\n typically is much shorter than most input values. If the algorithm\r\n is \"good\" as described in the \"O\" definition, then the hash\r\n function may be a candidate for use in a security mechanism to\r\n detect accidental changes in data, but not necessarily for a\r\n mechanism to detect changes made by active wiretapping. (See:\r\n Tutorial under \"checksum\".)\r\nShirey Informational [Page 140]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 167 of 436\n\nSecurity mechanisms require a \"cryptographic hash function\" (e.g.,\r\n MD2, MD4, MD5, SHA-1, Snefru), i.e., a good hash function that\r\n also has the one-way property and one of the two collision-free\r\n properties:\r\n - \"One-way property\": Given H and a hash result h = H(s), it is\r\n hard (i.e., computationally infeasible, \"impossible\") to find\r\n s. (Of course, given H and an input s, it must be relatively\r\n easy to compute the hash result H(s).)\r\n - \"Weakly collision-free property\": Given H and an input s, it is\r\n hard (i.e., computationally infeasible, \"impossible\") to find a\r\n different input, s', such that H(s) = H(s').\r\n - \"Strongly collision-free property\": Given H, it is hard to find\r\n any pair of inputs s and s' such that H(s) = H(s').\r\n If H produces a hash result N bits long, then to find an s' where\r\n H(s') = H(s) for a specific given s, the amount of computation\r\n required is O(2**n); i.e., it is necessary to try on the order of\r\n 2 to the power n values of s' before finding a collision. However,\r\n to simply find any pair of values s and s' that collide, the\r\n amount of computation required is only O(2**(n/2)); i.e., after\r\n computing H(s) for 2 to the power n/2 randomly chosen values of s,\r\n the probability is greater than 1/2 that two of those values have\r\n the same hash result. (See: birthday attack.)\r\n $ hash result\r\n 1. (I) The output of a hash function. (See: hash code, hash value.\r\n Compare: hash value.)\r\n 2. (O) \"The output produced by a hash function upon processing a\r\n message\" (where \"message\" is broadly defined as \"a digital\r\n representation of data\"). [DSG]\r\n Usage: IDOCs SHOULD avoid the unusual usage of \"message\" that is\r\n seen in the \"O\" definition.\r\n $ hash value\r\n (D) Synonym for \"hash result\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term for the output of\r\n a hash function; the term could easily be confused with \"hashed\r\n value\", which means the input to a hash function. (See: hash code,\r\n hash result, message digest.)\r\n $ HDM\r\n (O) See: Hierarchical Development Methodology.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 168 of 436\n\nShirey Informational [Page 141]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Hierarchical Development Methodology (HDM)\r\n (O) A methodology, language, and integrated set of software tools\r\n developed at SRI International for specifying, coding, and\r\n verifying software to produce correct and reliable programs.\r\n [Cheh]\r\n $ hierarchical PKI\r\n (I) A PKI architecture based on a certification hierarchy.\r\n (Compare: mesh PKI, trust-file PKI.)\r\n $ hierarchy management\r\n (I) The process of generating configuration data and issuing\r\n public-key certificates to build and operate a certification\r\n hierarchy. (See: certificate management.)\r\n $ hierarchy of trust\r\n (D) Synonym for \"certification hierarchy\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it mixes concepts\r\n in a potentially misleading way. (See: certification hierarchy,\r\n trust, web of trust.)\r\n $ high-assurance guard\r\n (O) \"An oxymoron,\" said Lt. Gen. William H. Campbell, former U.S.\r\n Army chief information officer, speaking at an Armed Forces\r\n Communications and Electronics Association conference.\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the term mixes concepts and could easily be misunderstood.\r\n $ hijack attack\r\n (I) A form of active wiretapping in which the attacker seizes\r\n control of a previously established communication association.\r\n (See: man-in-the-middle attack, pagejacking, piggyback attack.)\r\n $ HIPAA\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 169 of 436\n\n(N) Health Information Portability and Accountability Act of 1996,\r\n a U.S. law (Public Law 104-191) that is intended to protect the\r\n privacy of patients' medical records and other health information\r\n in all forms, and mandates security for that information,\r\n including for its electronic storage and transmission.\r\n $ HMAC\r\n (I) A keyed hash [R2104] that can be based on any iterated\r\n cryptographic hash (e.g., MD5 or SHA-1), so that the cryptographic\r\n strength of HMAC depends on the properties of the selected\r\n cryptographic hash. (See: [R2202, R2403, R2404].)\r\nShirey Informational [Page 142]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Derivation: Hash-based MAC. (Compare: CMAC.)\r\n Tutorial: Assume that H is a generic cryptographic hash in which a\r\n function is iterated on data blocks of length B bytes. L is the\r\n length of the of hash result of H. K is a secret key of length L\r\n \u003c= K \u003c= B. The values IPAD and OPAD are fixed strings used as\r\n inner and outer padding and defined as follows: IPAD = the byte\r\n 0x36 repeated B times, and OPAD = the byte 0x5C repeated B times.\r\n HMAC is computed by H(K XOR OPAD, H(K XOR IPAD, inputdata)).\r\n HMAC has the following goals:\r\n - To use available cryptographic hash functions without\r\n modification, particularly functions that perform well in\r\n software and for which software is freely and widely available.\r\n - To preserve the original performance of the selected hash\r\n without significant degradation.\r\n - To use and handle keys in a simple way.\r\n - To have a well-understood cryptographic analysis of the\r\n strength of the mechanism based on reasonable assumptions about\r\n the underlying hash function.\r\n - To enable easy replacement of the hash function in case a\r\n faster or stronger hash is found or required.\r\n $ honey pot\r\n (N) A system (e.g., a web server) or system resource (e.g., a file\r\n on a server) that is designed to be attractive to potential\r\n crackers and intruders, like honey is attractive to bears. (See:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 170 of 436\n\nentrapment.)\r\n Usage: It is likely that other cultures use different metaphors\r\n for this concept. Therefore, to avoid international\r\n misunderstanding, an IDOC SHOULD NOT use this term without\r\n providing a definition for it. (See: Deprecated Usage under \"Green\r\n Book\".)\r\n $ host\r\n 1. (I) /general/ A computer that is attached to a communication\r\n subnetwork or internetwork and can use services provided by the\r\n network to exchange data with other attached systems. (See: end\r\n system. Compare: server.)\r\n 2. (I) /IPS/ A networked computer that does not forward IP packets\r\n that are not addressed to the computer itself. (Compare: router.)\r\n Derivation: As viewed by its users, a host \"entertains\" them,\r\n providing Application-Layer services or access to other computers\r\n attached to the network. However, even though some traditional\r\n peripheral service devices, such as printers, can now be\r\nShirey Informational [Page 143]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n independently connected to networks, they are not usually called\r\n hosts.\r\n $ HTML\r\n (I) See: Hypertext Markup Language.\r\n $ HTTP\r\n (I) See: Hypertext Transfer Protocol.\r\n $ https\r\n (I) When used in the first part of a URL (the part that precedes\r\n the colon and specifies an access scheme or protocol), this term\r\n specifies the use of HTTP enhanced by a security mechanism, which\r\n is usually SSL. (Compare: S-HTTP.)\r\n $ human error\r\n (I) /threat action/ See: secondary definitions under \"corruption\",\r\n \"exposure\", and \"incapacitation\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 171 of 436\n\n$ hybrid encryption\r\n (I) An application of cryptography that combines two or more\r\n encryption algorithms, particularly a combination of symmetric and\r\n asymmetric encryption. Examples: digital envelope, MSP, PEM, PGP.\r\n (Compare: superencryption.)\r\n Tutorial: Asymmetric algorithms require more computation than\r\n equivalently strong symmetric ones. Thus, asymmetric encryption is\r\n not normally used for data confidentiality except to distribute a\r\n symmetric key in a hybrid encryption scheme, where the symmetric\r\n key is usually very short (in terms of bits) compared to the data\r\n file it protects. (See: bulk key.)\r\n $ hyperlink\r\n (I) In hypertext or hypermedia, an information object (such as a\r\n word, a phrase, or an image, which usually is highlighted by color\r\n or underscoring) that points (i.e., indicates how to connect) to\r\n related information that is located elsewhere and can be retrieved\r\n by activating the link (e.g., by selecting the object with a mouse\r\n pointer and then clicking).\r\n $ hypermedia\r\n (I) A generalization of hypertext; any media that contain\r\n hyperlinks that point to material in the same or another data\r\n object.\r\nShirey Informational [Page 144]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ hypertext\r\n (I) A computer document, or part of a document, that contains\r\n hyperlinks to other documents; i.e., text that contains active\r\n pointers to other text. Usually written in HTML and accessed using\r\n a web browser. (See: hypermedia.)\r\n $ Hypertext Markup Language (HTML)\r\n (I) A platform-independent system of syntax and semantics (RFC\r\n 1866) for adding characters to data files (particularly text\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 172 of 436\n\nfiles) to represent the data's structure and to point to related\r\n data, thus creating hypertext for use in the World Wide Web and\r\n other applications. (Compare: XML.)\r\n $ Hypertext Transfer Protocol (HTTP)\r\n (I) A TCP-based, Application-Layer, client-server, Internet\r\n protocol (RFC 2616) that is used to carry data requests and\r\n responses in the World Wide Web. (See: hypertext.)\r\n $ IAB\r\n (I) See: Internet Architecture Board.\r\n $ IANA\r\n (I) See: Internet Assigned Numbers Authority.\r\n $ IATF\r\n (O) See: Information Assurance Technical Framework.\r\n $ ICANN\r\n (I) See: Internet Corporation for Assigned Names and Numbers.\r\n $ ICMP\r\n (I) See: Internet Control Message Protocol.\r\n $ ICMP flood\r\n (I) A denial-of-service attack that sends a host more ICMP echo\r\n request (\"ping\") packets than the protocol implementation can\r\n handle. (See: flooding, smurf.)\r\n $ ICRL\r\n (N) See: indirect certificate revocation list.\r\n $ IDEA\r\n (N) See: International Data Encryption Algorithm.\r\n $ identification\r\n (I) An act or process that presents an identifier to a system so\r\n that the system can recognize a system entity and distinguish it\r\n from other entities. (See: authentication.)\r\nShirey Informational [Page 145]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 173 of 436\n\n$ identification information\r\n (D) Synonym for \"identifier\"; synonym for \"authentication\r\n information\". (See: authentication, identifying information.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n either of those terms; this term (a) is not as precise as they are\r\n and (b) mixes concepts in a potentially misleading way. Instead,\r\n use \"identifier\" or \"authentication information\", depending on\r\n what is meant.\r\n $ Identification Protocol\r\n (I) A client-server Internet protocol [R1413] for learning the\r\n identity of a user of a particular TCP connection.\r\n Tutorial: Given a TCP port number pair, the server returns a\r\n character string that identifies the owner of that connection on\r\n the server's system. The protocol does not provide an\r\n authentication service and is not intended for authorization or\r\n access control. At best, it provides additional auditing\r\n information with respect to TCP.\r\n $ identifier\r\n (I) A data object -- often, a printable, non-blank character\r\n string -- that definitively represents a specific identity of a\r\n system entity, distinguishing that identity from all others.\r\n (Compare: identity.)\r\n Tutorial: Identifiers for system entities must be assigned very\r\n carefully, because authenticated identities are the basis for\r\n other security services, such as access control service.\r\n $ identifier credential\r\n 1. (I) See: /authentication/ under \"credential\".\r\n 2. (D) Synonym for \"signature certificate\".\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the term is used in many ways and could easily be\r\n misunderstood.\r\n $ identifying information\r\n (D) Synonym for \"identifier\"; synonym for \"authentication\r\n information\". (See: authentication, identification information.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n either of those terms; this term (a) is not as precise as they are\r\n and (b) mixes concepts in a potentially misleading way. Instead,\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 174 of 436\n\nShirey Informational [Page 146]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n use \"identifier\" or \"authentication information\", depending on\r\n what is meant.\r\n $ identity\r\n (I) The collective aspect of a set of attribute values (i.e., a\r\n set of characteristics) by which a system user or other system\r\n entity is recognizable or known. (See: authenticate, registration.\r\n Compare: identifier.)\r\n Usage: An IDOC MAY apply this term to either a single entity or a\r\n set of entities. If an IDOC involves both meanings, the IDOC\r\n SHOULD use the following terms and definitions to avoid ambiguity:\r\n - \"Singular identity\": An identity that is registered for an\r\n entity that is one person or one process.\r\n - \"Shared identity\": An identity that is registered for an entity\r\n that is a set of singular entities (1) in which each member is\r\n authorized to assume the identity individually and (2) for\r\n which the registering system maintains a record of the singular\r\n entities that comprise the set. In this case, we would expect\r\n each member entity to be registered with a singular identity\r\n before becoming associated with the shared identity.\r\n - \"Group identity\": An identity that is registered for an entity\r\n (1) that is a set of entities (2) for which the registering\r\n system does not maintain a record of singular entities that\r\n comprise the set.\r\n Tutorial: When security services are based on identities, two\r\n properties are desirable for the set of attributes used to define\r\n identities:\r\n - The set should be sufficient to distinguish each entity from\r\n all other entities, i.e., to represent each entity uniquely.\r\n - The set should be sufficient to distinguish each identity from\r\n any other identities of the same entity.\r\n The second property is needed if a system permits an entity to\r\n register two or more concurrent identities. Having two or more\r\n identities for the same entity implies that the entity has two\r\n separate justifications for registration. In that case, the set of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 175 of 436\n\nattributes used for identities must be sufficient to represent\r\n multiple identities for a single entity.\r\n Having two or more identities registered for the same entity is\r\n different from concurrently associating two different identifiers\r\n with the same identity, and also is different from a single\r\n identity concurrently accessing the system in two different roles.\r\n (See: principal, role-based access control.)\r\nShirey Informational [Page 147]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n When an identity of a user is being registered in a system, the\r\n system may require presentation of evidence that proves the\r\n identity's authenticity (i.e., that the user has the right to\r\n claim or use the identity) and its eligibility (i.e., that the\r\n identity is qualified to be registered and needs to be\r\n registered).\r\n The following diagram illustrates how this term relates to some\r\n other terms in a PKI system: authentication information,\r\n identifier, identifier credential, registration, registered user,\r\n subscriber, and user.\r\n Relationships: === one-to-one, ==\u003e one-to-many, \u003c=\u003e many-to-many.\r\n +- - - - - - - - - - - - - - - - - - - - - - - - - - +\r\n | PKI System |\r\n + - - - - + | +------------------+ +-------------------------+ |\r\n | User, | | |Subscriber, i.e., | | Identity of Subscriber | |\r\n |i.e., one| | | Registered User, | | is system-unique | |\r\n | of the | | | is system-unique | | +---------------------+ | |\r\n |following| | | +--------------+ | | | Subscriber | | |\r\n | | | | | User's core | | | | Identity's | | |\r\n | +-----+ |===| | Registration | |==\u003e| | Registration data | | |\r\n | |human| | | | | data, i.e., | | | |+-------------------+| | |\r\n | |being| | | | | an entity's | | | || same core data || | |\r\n | +-----+ | | | |distinguishing|========|for all Identities || | |\r\n | or | | | | attribute | | | || of the same User || | |\r\n | +-----+ | | | | values | | +===|+-------------------+| | |\r\n | |auto-| | | | +--------------+ | | | +---------------------+ | |\r\n | |mated| | | +------------------+ | +------------|------------+ |\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 176 of 436\n\n| |pro- | | | | +=======+ | |\r\n | |cess | | | +-------v----|----------------------|------------+ |\r\n | +-----+ | | | +----------v---+ +------------v----------+ | |\r\n | or | | | |Authentication|\u003c===\u003e|Identifier of Identity | | |\r\n |+-------+| | | | Information | | is system-unique | | |\r\n || a set || | | +--------------+ +-----------------------+ | |\r\n || of || | | Identifier Credential that associates unit of | |\r\n || either|| | | Authentication Information with the Identifier | |\r\n |+-------+| | +------------------------------------------------+ |\r\n + - - - - + + - - - - - - - - - - - - - - - - - - - - - - - - - -+\r\n $ identity-based security policy\r\n (I) \"A security policy based on the identities and/or attributes\r\n of users, a group of users, or entities acting on behalf of the\r\n users and the resources/objects being accessed.\" [I7498-2] (See:\r\n rule-based security policy.)\r\nShirey Informational [Page 148]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ identity proofing\r\n (I) A process that vets and verifies the information that is used\r\n to establish the identity of a system entity. (See: registration.)\r\n $ IDOC\r\n (I) An abbreviation used in this Glossary to refer to a document\r\n or other item of written material that is generated in the\r\n Internet Standards Process (RFC 2026), i.e., an RFC, an Internet-\r\n Draft, or some other item of discourse.\r\n Deprecated Usage: This abbreviation SHOULD NOT be used in an IDOC\r\n unless it is first defined in the IDOC because the abbreviation\r\n was invented for this Glossary and is not widely known.\r\n $ IDS\r\n (I) See: intrusion detection system.\r\n $ IEEE\r\n (N) See: Institute of Electrical and Electronics Engineers, Inc.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 177 of 436\n\n$ IEEE 802.10\r\n (N) An IEEE committee developing security standards for LANs.\r\n (See: SILS.)\r\n $ IEEE P1363\r\n (N) An IEEE working group, Standard for Public-Key Cryptography,\r\n engaged in developing a comprehensive reference standard for\r\n asymmetric cryptography. Covers discrete logarithm (e.g., DSA),\r\n elliptic curve, and integer factorization (e.g., RSA); and covers\r\n key agreement, digital signature, and encryption.\r\n $ IESG\r\n (I) See: Internet Engineering Steering Group.\r\n $ IETF\r\n (I) See: Internet Engineering Task Force.\r\n $ IKE\r\n (I) See: IPsec Key Exchange.\r\n $ IMAP4\r\n (I) See: Internet Message Access Protocol, version 4.\r\n $ IMAP4 AUTHENTICATE\r\n (I) An IMAP4 command (better described as a transaction type, or\r\n subprotocol) by which an IMAP4 client optionally proposes a\r\n mechanism to an IMAP4 server to authenticate the client to the\r\n server and provide other security services. (See: POP3.)\r\nShirey Informational [Page 149]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: If the server accepts the proposal, the command is\r\n followed by performing a challenge-response authentication\r\n protocol and, optionally, negotiating a protection mechanism for\r\n subsequent POP3 interactions. The security mechanisms that are\r\n used by IMAP4 AUTHENTICATE -- including Kerberos, GSS-API, and\r\n S/Key -- are described in [R1731].\r\n $ impossible\r\n (O) Cannot be done in any reasonable amount of time. (See: break,\r\n brute force, strength, work factor.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 178 of 436\n\n$ in the clear\r\n (I) Not encrypted. (See: clear text.)\r\n $ Ina Jo\r\n (O) A methodology, language, and integrated set of software tools\r\n developed at the System Development Corporation for specifying,\r\n coding, and verifying software to produce correct and reliable\r\n programs. Usage: a.k.a. the Formal Development Methodology. [Cheh]\r\n $ incapacitation\r\n (I) A type of threat action that prevents or interrupts system\r\n operation by disabling a system component. (See: disruption.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Malicious logic\": In context of incapacitation, any hardware,\r\n firmware, or software (e.g., logic bomb) intentionally\r\n introduced into a system to destroy system functions or\r\n resources. (See: corruption, main entry for \"malicious logic\",\r\n masquerade, misuse.)\r\n - \"Physical destruction\": Deliberate destruction of a system\r\n component to interrupt or prevent system operation.\r\n - \"Human error\": /incapacitation/ Action or inaction that\r\n unintentionally disables a system component. (See: corruption,\r\n exposure.)\r\n - \"Hardware or software error\": /incapacitation/ Error that\r\n unintentionally causes failure of a system component and leads\r\n to disruption of system operation. (See: corruption, exposure.)\r\n - \"Natural disaster\": /incapacitation/ Any \"act of God\" (e.g.,\r\n fire, flood, earthquake, lightning, or wind) that disables a\r\n system component. [FP031 Section 2]\r\n $ incident\r\n See: security incident.\r\n $ INCITS\r\n (N) See: \"International Committee for Information Technology\r\n Standardization\" under \"ANSI\".\r\nShirey Informational [Page 150]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ indicator\r\n (N) An action -- either specific, generalized, or theoretical --\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 179 of 436\n\nthat an adversary might be expected to take in preparation for an\r\n attack. [C4009] (See: \"attack sensing, warning, and response\".\r\n Compare: message indicator.)\r\n $ indirect attack\r\n (I) See: secondary definition under \"attack\". Compare: direct\r\n attack.\r\n $ indirect certificate revocation list (ICRL)\r\n (N) In X.509, a CRL that may contain certificate revocation\r\n notifications for certificates issued by CAs other than the issuer\r\n (i.e., signer) of the ICRL.\r\n $ indistinguishability\r\n (I) An attribute of an encryption algorithm that is a\r\n formalization of the notion that the encryption of some string is\r\n indistinguishable from the encryption of an equal-length string of\r\n nonsense. (Compare: semantic security.)\r\n $ inference\r\n 1. (I) A type of threat action that reasons from characteristics\r\n or byproducts of communication and thereby indirectly accesses\r\n sensitive data, but not necessarily the data contained in the\r\n communication. (See: traffic analysis, signal analysis.)\r\n 2. (I) A type of threat action that indirectly gains unauthorized\r\n access to sensitive information in a database management system by\r\n correlating query responses with information that is already\r\n known.\r\n $ inference control\r\n (I) Protection of data confidentiality against inference attack.\r\n (See: traffic-flow confidentiality.)\r\n Tutorial: A database management system containing N records about\r\n individuals may be required to provide statistical summaries about\r\n subsets of the population, while not revealing sensitive\r\n information about a single individual. An attacker may try to\r\n obtain sensitive information about an individual by isolating a\r\n desired record at the intersection of a set of overlapping\r\n queries. A system can attempt to prevent this by restricting the\r\n size and overlap of query sets, distorting responses by rounding\r\n or otherwise perturbing database values, and limiting queries to\r\n random samples. However, these techniques may be impractical to\r\n implement or use, and no technique is totally effective. For\r\n example, restricting the minimum size of a query set -- that is,\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 180 of 436\n\nShirey Informational [Page 151]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n not responding to queries for which there are fewer than K or more\r\n than N-K records that satisfy the query -- usually cannot prevent\r\n unauthorized disclosure. An attacker can pad small query sets with\r\n extra records, and then remove the effect of the extra records.\r\n The formula for identifying the extra records is called the\r\n \"tracker\". [Denns]\r\n $ INFOCON\r\n (O) See: information operations condition\r\n $ informal\r\n (N) Expressed in natural language. [CCIB] (Compare: formal,\r\n semiformal.)\r\n $ information\r\n 1. (I) Facts and ideas, which can be represented (encoded) as\r\n various forms of data.\r\n 2. (I) Knowledge -- e.g., data, instructions -- in any medium or\r\n form that can be communicated between system entities.\r\n Tutorial: Internet security could be defined simply as protecting\r\n information in the Internet. However, the perceived need to use\r\n different protective measures for different types of information\r\n (e.g., authentication information, classified information,\r\n collateral information, national security information, personal\r\n information, protocol control information, sensitive compartmented\r\n information, sensitive information) has led to the diversity of\r\n terminology listed in this Glossary.\r\n $ information assurance\r\n (N) /U.S. Government/ \"Measures that protect and defend\r\n information and information systems by ensuring their availability\r\n integrity, authentication, confidentiality, and non-repudiation.\r\n These measures include providing for restoration of information\r\n systems by incorporating protection, detection, and reaction\r\n capabilities.\" [C4009]\r\n $ Information Assurance Technical Framework (IATF)\r\n (O) A publicly available document [IATF], developed through a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 181 of 436\n\ncollaborative effort by organizations in the U.S. Government and\r\n industry, and issued by NSA. Intended for security managers and\r\n system security engineers as a tutorial and reference document\r\n about security problems in information systems and networks, to\r\n improve awareness of tradeoffs among available technology\r\n solutions and of desired characteristics of security approaches\r\n for particular problems. (See: ISO 17799, [SP14].)\r\nShirey Informational [Page 152]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ information domain\r\n (O) See: secondary definition under \"domain\".\r\n $ information domain security policy\r\n (O) See: secondary definition under \"domain\".\r\n $ information flow policy\r\n (N) /formal model/ A triple consisting of a set of security levels\r\n (or their equivalent security labels), a binary operator that maps\r\n each pair of security levels into a security level, and a binary\r\n relation on the set that selects a set of pairs of levels such\r\n that information is permitted to flow from an object of the first\r\n level to an object of the second level. (See: flow control,\r\n lattice model.)\r\n $ information operations condition (INFOCON)\r\n (O) /U.S. DoD/ A comprehensive defense posture and response based\r\n on the status of information systems, military operations, and\r\n intelligence assessments of adversary capabilities and intent.\r\n (See: threat)\r\n Derivation: From DEFCON, i.e., defense condition.\r\n Tutorial: The U.S. DoD defines five INFOCON levels: NORMAL (normal\r\n activity), ALPHA (increased risk of attack), BRAVO (specific risk\r\n of attack), CHARLIE (limited attack), and DELTA (general attack).\r\n $ information security (INFOSEC)\r\n (N) Measures that implement and assure security services in\r\n information systems, including in computer systems (see: COMPUSEC)\r\n and in communication systems (see: COMSEC).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 182 of 436\n\n$ information system\r\n (I) An organized assembly of computing and communication resources\r\n and procedures -- i.e., equipment and services, together with\r\n their supporting infrastructure, facilities, and personnel -- that\r\n create, collect, record, process, store, transport, retrieve,\r\n display, disseminate, control, or dispose of information to\r\n accomplish a specified set of functions. (See: system entity,\r\n system resource. Compare: computer platform.)\r\n $ Information Technology Security Evaluation Criteria (ITSEC)\r\n (N) A Standard [ITSEC] jointly developed by France, Germany, the\r\n Netherlands, and the United Kingdom for use in the European Union;\r\n accommodates a wider range of security assurance and functionality\r\n combinations than the TCSEC. Superseded by the Common Criteria.\r\nShirey Informational [Page 153]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ INFOSEC\r\n (I) See: information security.\r\n $ ingress filtering\r\n (I) A method [R2827] for countering attacks that use packets with\r\n false IP source addresses, by blocking such packets at the\r\n boundary between connected networks.\r\n Tutorial: Suppose network A of an internet service provider (ISP)\r\n includes a filtering router that is connected to customer network\r\n B, and an attacker in B at IP source address \"foo\" attempts to\r\n send packets with false source address \"bar\" into A. The false\r\n address may be either fixed or randomly changing, and it may\r\n either be unreachable or be a forged address that legitimately\r\n exists within either B or some other network C. In ingress\r\n filtering, the ISP's router blocks all inbound packet that arrive\r\n from B with a source address that is not within the range of\r\n legitimately advertised addresses for B. This method does not\r\n prevent all attacks that can originate from B, but the actual\r\n source of such attacks can be more easily traced because the\r\n originating network is known.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 183 of 436\n\n$ initialization value (IV)\r\n (I) /cryptography/ An input parameter that sets the starting state\r\n of a cryptographic algorithm or mode. (Compare: activation data.)\r\n Tutorial: An IV can be used to synchronize one cryptographic\r\n process with another; e.g., CBC, CFB, and OFB use IVs. An IV also\r\n can be used to introduce cryptographic variance (see: salt)\r\n besides that provided by a key.\r\n $ initialization vector\r\n (D) /cryptography/ Synonym for \"initialization value\".\r\n Deprecated Term: To avoid international misunderstanding, IDOCs\r\n SHOULD NOT use this term in the context of cryptography because\r\n most dictionary definitions of \"vector\" includes a concept of\r\n direction or magnitude, which are irrelevant to cryptographic use.\r\n $ insertion\r\n 1. (I) /packet/ See: secondary definition under \"stream integrity\r\n service\".\r\n 2. (I) /threat action/ See: secondary definition under\r\n \"falsification\".\r\n $ inside attack\r\n (I) See: secondary definition under \"attack\". Compare: insider.\r\nShirey Informational [Page 154]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ insider\r\n 1. (I) A user (usually a person) that accesses a system from a\r\n position that is inside the system's security perimeter. (Compare:\r\n authorized user, outsider, unauthorized user.)\r\n Tutorial: An insider has been assigned a role that has more\r\n privileges to access system resources than do some other types of\r\n users, or can access those resources without being constrained by\r\n some access controls that are applied to outside users. For\r\n example, a salesclerk is an insider who has access to the cash\r\n register, but a store customer is an outsider.\r\n The actions performed by an insider in accessing the system may be\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 184 of 436\n\neither authorized or unauthorized; i.e., an insider may act either\r\n as an authorized user or as an unauthorized user.\r\n 2. (O) A person with authorized physical access to the system.\r\n Example: In this sense, an office janitor is an insider, but a\r\n burglar or casual visitor is not. [NRC98]\r\n 3. (O) A person with an organizational status that causes the\r\n system or members of the organization to view access requests as\r\n being authorized. Example: In this sense, a purchasing agent is an\r\n insider but a vendor is not. [NRC98]\r\n $ inspectable space\r\n (O) /EMSEC/ \"Three-dimensional space surrounding equipment that\r\n process classified and/or sensitive information within which\r\n TEMPEST exploitation is not considered practical or where legal\r\n authority to identify and/or remove a potential TEMPEST\r\n exploitation exists.\" [C4009] (Compare: control zone, TEMPEST\r\n zone.)\r\n $ Institute of Electrical and Electronics Engineers, Inc. (IEEE)\r\n (N) The IEEE is a not-for-profit association of approximately\r\n 300,000 individual members in 150 countries. The IEEE produces\r\n nearly one third of the world's published literature in electrical\r\n engineering, computers, and control technology; holds hundreds of\r\n major, annual conferences; and maintains more than 800 active\r\n standards, with many more under development. (See: SILS.)\r\n $ integrity\r\n See: data integrity, datagram integrity service, correctness\r\n integrity, source integrity, stream integrity service, system\r\n integrity.\r\nShirey Informational [Page 155]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ integrity check\r\n (D) A computation that is part of a mechanism to provide data\r\n integrity service or data origin authentication service. (Compare:\r\n checksum.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 185 of 436\n\nDeprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"cryptographic hash\" or \"protected checksum\". This term\r\n unnecessarily duplicates the meaning of other, well-established\r\n terms; this term only mentions integrity, even though the intended\r\n service may be data origin authentication; and not every checksum\r\n is cryptographically protected.\r\n $ integrity label\r\n (I) A security label that tells the degree of confidence that may\r\n be placed in the data, and may also tell what countermeasures are\r\n required to be applied to protect the data from alteration and\r\n destruction. (See: integrity. Compare: classification label.)\r\n $ intelligent threat\r\n (I) A circumstance in which an adversary has the technical and\r\n operational ability to detect and exploit a vulnerability and also\r\n has the demonstrated, presumed, or inferred intent to do so. (See:\r\n threat.)\r\n $ interception\r\n (I) A type of threat action whereby an unauthorized entity\r\n directly accesses sensitive data while the data is traveling\r\n between authorized sources and destinations. (See: unauthorized\r\n disclosure.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Theft\": Gaining access to sensitive data by stealing a\r\n shipment of a physical medium, such as a magnetic tape or disk,\r\n that holds the data.\r\n - \"Wiretapping (passive)\": Monitoring and recording data that is\r\n flowing between two points in a communication system. (See:\r\n wiretapping.)\r\n - \"Emanations analysis\": Gaining direct knowledge of communicated\r\n data by monitoring and resolving a signal that is emitted by a\r\n system and that contains the data but was not intended to\r\n communicate the data. (See: emanation.)\r\n $ interference\r\n (I) /threat action/ See: secondary definition under \"obstruction\".\r\n $ intermediate CA\r\n (D) The CA that issues a cross-certificate to another CA. [X509]\r\n (See: cross-certification.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 186 of 436\n\nShirey Informational [Page 156]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is not\r\n widely known and mixes concepts in a potentially misleading way.\r\n For example, suppose that end entity 1 (\"EE1) is in one PKI\r\n (\"PKI1\"), end entity 2 (\"EE2) is in another PKI (\"PKI2\"), and the\r\n root in PKI1 (\"CA1\") cross-certifies the root CA in PKI2 (\"CA2\").\r\n Then, if EE1 constructs the certification path CA1-to-CA2-to-EE2\r\n to validate a certificate of EE2, conventional English usage would\r\n describe CA2 as being in the \"intermediate\" position in that path,\r\n not CA1.\r\n $ internal controls\r\n (I) /COMPUSEC/ Functions, features, and technical characteristics\r\n of computer hardware and software, especially of operating\r\n systems. Includes mechanisms to regulate the operation of a\r\n computer system with regard to access control, flow control, and\r\n inference control. (Compare: external controls.)\r\n $ International Data Encryption Algorithm (IDEA)\r\n (N) A patented, symmetric block cipher that uses a 128-bit key and\r\n operates on 64-bit blocks. [Schn] (See: symmetric cryptography.)\r\n $ International Standard\r\n (N) See: secondary definition under \"ISO\".\r\n $ International Traffic in Arms Regulations (ITAR)\r\n (O) Rules issued by the U.S. State Department, by authority of the\r\n Arms Export Control Act (22 U.S.C. 2778), to control export and\r\n import of defense articles and defense services, including\r\n information security systems, such as cryptographic systems, and\r\n TEMPEST suppression technology. (See: type 1 product, Wassenaar\r\n Arrangement.)\r\n $ internet, Internet\r\n 1. (I) /not capitalized/ Abbreviation of \"internetwork\".\r\n 2. (I) /capitalized/ The Internet is the single, interconnected,\r\n worldwide system of commercial, governmental, educational, and\r\n other computer networks that share (a) the protocol suite\r\n specified by the IAB (RFC 2026) and (b) the name and address\r\n spaces managed by the ICANN. (See: Internet Layer, Internet\r\n Protocol Suite.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 187 of 436\n\nUsage: Use with definite article (\"the\") when using as a noun. For\r\n example, say \"My LAN is small, but the Internet is large.\" Don't\r\n say \"My LAN is small, but Internet is large.\"\r\nShirey Informational [Page 157]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Internet Architecture Board (IAB)\r\n (I) A technical advisory group of the ISOC, chartered by the ISOC\r\n Trustees to provide oversight of Internet architecture and\r\n protocols and, in the context of Internet Standards, a body to\r\n which decisions of the IESG may be appealed. Responsible for\r\n approving appointments to the IESG from among nominees submitted\r\n by the IETF nominating committee. (RFC 2026)\r\n $ Internet Assigned Numbers Authority (IANA)\r\n (I) From the early days of the Internet, the IANA was chartered by\r\n the ISOC and the U.S. Government's Federal Network Council to be\r\n the central coordination, allocation, and registration body for\r\n parameters for Internet protocols. Superseded by ICANN.\r\n $ Internet Control Message Protocol (ICMP)\r\n (I) An Internet Standard protocol (RFC 792) that is used to report\r\n error conditions during IP datagram processing and to exchange\r\n other information concerning the state of the IP network.\r\n $ Internet Corporation for Assigned Names and Numbers (ICANN)\r\n (I) The non-profit, private corporation that has assumed\r\n responsibility for the IP address space allocation, protocol\r\n parameter assignment, DNS management, and root server system\r\n management functions formerly performed under U.S. Government\r\n contract by IANA and other entities.\r\n Tutorial: The IPS, as defined by the IETF and the IESG, contains\r\n numerous parameters, such as Internet addresses, domain names,\r\n autonomous system numbers, protocol numbers, port numbers,\r\n management information base OIDs, including private enterprise\r\n numbers, and many others. The Internet community requires that the\r\n values used in these parameter fields be assigned uniquely. ICANN\r\n makes those assignments as requested and maintains a registry of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 188 of 436\n\nthe current values.\r\n ICANN was formed in October 1998, by a coalition of the Internet's\r\n business, technical, and academic communities. The U.S. Government\r\n designated ICANN to serve as the global consensus entity with\r\n responsibility for coordinating four key functions for the\r\n Internet: allocation of IP address space, assignment of protocol\r\n parameters, management of the DNS, and management of the DNS root\r\n server system.\r\n $ Internet-Draft\r\n (I) A working document of the IETF, its areas, and its working\r\n groups. (RFC 2026) (Compare: RFC.)\r\nShirey Informational [Page 158]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: The term is customarily hyphenated when used either as a\r\n adjective or a noun, even though the latter is not standard\r\n English punctuation.\r\n Tutorial: An Internet-Draft is not an archival document like an\r\n RFC is. Instead, an Internet-Draft is a preliminary or working\r\n document that is valid for a maximum of six months and may be\r\n updated, replaced, or made obsolete by other documents at any\r\n time. It is inappropriate to use an Internet-Draft as reference\r\n material or to cite it other than as a \"work in progress\".\r\n Although most of the Internet-Drafts are produced by the IETF, any\r\n interested organization may request to have its working documents\r\n published as Internet-Drafts.\r\n $ Internet Engineering Steering Group (IESG)\r\n (I) The part of the ISOC responsible for technical management of\r\n IETF activities and administration of the Internet Standards\r\n Process according to procedures approved by the ISOC Trustees.\r\n Directly responsible for actions along the \"standards track\",\r\n including final approval of specifications as Internet Standards.\r\n Composed of IETF Area Directors and the IETF chairperson, who also\r\n chairs the IESG. (RFC 2026)\r\n $ Internet Engineering Task Force (IETF)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 189 of 436\n\n(I) A self-organized group of people who make contributions to the\r\n development of Internet technology. The principal body engaged in\r\n developing Internet Standards, although not itself a part of the\r\n ISOC. Composed of Working Groups, which are arranged into Areas\r\n (such as the Security Area), each coordinated by one or more Area\r\n Directors. Nominations to the IAB and the IESG are made by a\r\n committee selected at random from regular IETF meeting attendees\r\n who have volunteered. (RFCs 2026, 3935) [R2323]\r\n $ Internet Key Exchange (IKE)\r\n (I) An Internet, IPsec, key-establishment protocol [R4306] for\r\n putting in place authenticated keying material (a) for use with\r\n ISAKMP and (b) for other security associations, such as in AH and\r\n ESP.\r\n Tutorial: IKE is based on three earlier protocol designs: ISAKMP,\r\n OAKLEY, and SKEME.\r\n $ Internet Layer\r\n (I) See: Internet Protocol Suite.\r\n $ Internet Message Access Protocol, version 4 (IMAP4)\r\n (I) An Internet protocol (RFC 2060) by which a client workstation\r\n can dynamically access a mailbox on a server host to manipulate\r\nShirey Informational [Page 159]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n and retrieve mail messages that the server has received and is\r\n holding for the client. (See: POP3.)\r\n Tutorial: IMAP4 has mechanisms for optionally authenticating a\r\n client to a server and providing other security services. (See:\r\n IMAP4 AUTHENTICATE.)\r\n $ Internet Open Trading Protocol (IOTP)\r\n (I) An Internet protocol [R2801] proposed as a general framework\r\n for Internet commerce, able to encapsulate transactions of various\r\n proprietary payment systems (e.g., GeldKarte, Mondex, SET, Visa\r\n Cash). Provides optional security services by incorporating\r\n various Internet security mechanisms (e.g., MD5) and protocols\r\n (e.g., TLS).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 190 of 436\n\n$ Internet Policy Registration Authority (IPRA)\r\n (I) An X.509-compliant CA that is the top CA of the Internet\r\n certification hierarchy operated under the auspices of the ISOC\r\n [R1422]. (See: /PEM/ under \"certification hierarchy\".)\r\n $ Internet Private Line Interface (IPLI)\r\n (O) A successor to the PLI, updated to use TCP/IP and newer\r\n military-grade COMSEC equipment (TSEC/KG-84). The IPLI was a\r\n portable, modular system that was developed for use in tactical,\r\n packet-radio networks. (See: end-to-end encryption.)\r\n $ Internet Protocol (IP)\r\n (I) An Internet Standard, Internet-Layer protocol that moves\r\n datagrams (discrete sets of bits) from one computer to another\r\n across an internetwork but does not provide reliable delivery,\r\n flow control, sequencing, or other end-to-end services that TCP\r\n provides. IP version 4 (IPv4) is specified in RFC 791, and IP\r\n version 6 (IPv6) is specified in RFC 2460. (See: IP address,\r\n TCP/IP.)\r\n Tutorial: If IP were used in an OSIRM stack, IP would be placed at\r\n the top of Layer 3, above other Layer 3 protocols in the stack.\r\n In any IPS stack, IP is always present in the Internet Layer and\r\n is always placed at the top of that layer, on top of any other\r\n protocols that are used in that layer. In some sense, IP is the\r\n only protocol specified for the IPS Internet Layer; other\r\n protocols used there, such as AH and ESP, are just IP variations.\r\n $ Internet Protocol security\r\n See: IP Security Protocol.\r\nShirey Informational [Page 160]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Internet Protocol Security Option (IPSO)\r\n (I) Refers to one of three types of IP security options, which are\r\n fields that may be added to an IP datagram for carrying security\r\n information about the datagram. (Compare: IPsec.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term without a\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 191 of 436\n\nmodifier to indicate which of the following three types is meant:\r\n - \"DoD Basic Security Option\" (IP option type 130): Defined for\r\n use on U.S. DoD common-use data networks. Identifies the DoD\r\n classification level at which the datagram is to be protected\r\n and the protection authorities whose rules apply to the\r\n datagram. (A \"protection authority\" is a National Access\r\n Program (e.g., GENSER, SIOP-ESI, SCI, NSA, Department of\r\n Energy) or Special Access Program that specifies protection\r\n rules for transmission and processing of the information\r\n contained in the datagram.) [R1108]\r\n - \"DoD Extended Security Option\" (IP option type 133): Permits\r\n additional security labeling information, beyond that present\r\n in the Basic Security Option, to be supplied in the datagram to\r\n meet the needs of registered authorities. [R1108]\r\n - \"Common IP Security Option\" (CIPSO) (IP option type 134):\r\n Designed by TSIG to carry hierarchic and non-hierarchic\r\n security labels. (Formerly called \"Commercial IP Security\r\n Option\"; a version 2.3 draft was published 9 March 1993 as an\r\n Internet-Draft but did not advance to RFC form.) [CIPSO]\r\n $ Internet Protocol Suite (IPS)\r\n (I) The set of network communication protocols that are specified\r\n by the IETF, and approved as Internet Standards by the IESG,\r\n within the oversight of the IAB. (See: OSIRM Security\r\n Architecture. Compare: OSIRM.)\r\n Usage: This set of protocols is popularly known as \"TCP/IP\"\r\n because TCP and IP are its most basic and important components.\r\n For clarity, this Glossary refers to IPS protocol layers by name\r\n and capitalizes those names, and refers to OSIRM protocol layers\r\n by number.\r\n Tutorial: The IPS does have architectural principles [R1958], but\r\n there is no Internet Standard that defines a layered IPS reference\r\n model like the OSIRM. Still, Internet community literature has\r\n referred (inconsistently) to IPS layers since early in the\r\n Internet's development [Padl].\r\nShirey Informational [Page 161]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 192 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n This Glossary treats the IPS as having five protocol layers --\r\n Application, Transport, Internet, Network Interface, and Network\r\n Hardware (or Network Substrate) -- which are illustrated in the\r\n following diagram:\r\n OSIRM Layers Examples IPS Layers Examples\r\n ------------------ --------------- --------------- --------------\r\n Message Format: P2 [X420] Message Format: ARPA (RFC 822)\r\n +----------------+ +-------------+\r\n |7.Application | P1 [X419] | Application | SMTP (RFC 821)\r\n +----------------+ - - - - - - | |\r\n |6.Presentation | [I8823] | |\r\n +----------------+ - - - - - - | |\r\n |5.Session | [I8327] +-------------+\r\n +----------------+ - - - - - - | Transport | TCP (RFC 793)\r\n |4.Transport | TP4 [I8073] | |\r\n +----------------+ - - - - - - +-------------+\r\n |3.Network | CLNP [I8473] | Internet | IP (RFC 791)\r\n | | +-------------+\r\n | | | Network | IP over IEEE\r\n +----------------+ - - - - - - | Interface | 802 (RFC 1042)\r\n |2.Data Link | +-------------+\r\n | | LLC [I8802-2] - Network - The IPS does\r\n | | MAC [I8802-3] - Hardware - not include\r\n +----------------+ - (or Network - standards for\r\n |1.Physical | Baseband - Substrate) - this layer.\r\n +----------------+ Signaling [Stal] + - - - - - - +\r\n The diagram approximates how the five IPS layers align with the\r\n seven OSIRM layers, and it offers examples of protocol stacks that\r\n provide roughly equivalent electronic mail service over a private\r\n LAN that uses baseband signaling.\r\n - IPS Application Layer: The user runs an application program.\r\n The program selects the data transport service it needs --\r\n either a sequence of data messages or a continuous stream of\r\n data -- and hands application data to the Transport Layer for\r\n delivery.\r\n - IPS Transport Layer: This layer divides application data into\r\n packets, adds a destination address to each, and communicates\r\n them end-to-end -- from one application program to another --\r\n optionally regulating the flow and ensuring reliable (error-\r\n free and sequenced) delivery.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 193 of 436\n\n- IPS Internet Layer: This layer carries transport packets in IP\r\n datagrams. It moves each datagram independently, from its\r\n source computer to its addressed destination computer, routing\r\nShirey Informational [Page 162]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n the datagram through a sequence of networks and relays and\r\n selecting appropriate network interfaces en route.\r\n - IPS Network Interface Layer: This layer accepts datagrams for\r\n transmission over a specific network. This layer specifies\r\n interface conventions for carrying IP over OSIRM Layer 3\r\n protocols and over Media Access Control sublayer protocols of\r\n OSIRM Layer 2. An example is IP over IEEE 802 (RFD 1042).\r\n - IPS Network Hardware Layer: This layer consists of specific,\r\n physical communication media. However, the IPS does not specify\r\n its own peer-to-peer protocols in this layer. Instead, the\r\n layering conventions specified by the Network Interface Layer\r\n use Layer 2 and Layer 3 protocols that are specified by bodies\r\n other than the IETF. That is, the IPS addresses *inter*-network\r\n functions and does not address *intra*-network functions.\r\n The two models are most dissimilar in the upper layers, where the\r\n IPS model does not include Session and Presentation layers.\r\n However, this omission causes fewer functional differences between\r\n the models than might be imagined, and the differences have\r\n relatively few security implications:\r\n - Formal separation of OSIRM Layers 5, 6, and 7 is not needed in\r\n implementations; the functions of these layers sometimes are\r\n mixed in a single software unit, even in protocols in the OSI\r\n suite.\r\n - Some OSIRM Layer 5 services -- for example, connection\r\n termination -- are built into TCP, and the remaining Layer 5\r\n and 6 functions are built into IPS Application-Layer protocols\r\n where needed.\r\n - The OSIRM does not place any security services in Layer 5 (see:\r\n OSIRM Security Architecture).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 194 of 436\n\n- The lack of an explicit Presentation Layer in the IPS sometimes\r\n makes it simpler to implement security in IPS applications. For\r\n example, a primary function of Layer 6 is to convert data\r\n between internal and external forms, using a transfer syntax to\r\n unambiguously encode data for transmission. If an OSIRM\r\n application encrypts data to protect against disclosure during\r\n transmission, the transfer encoding must be done before the\r\n encryption. If an application does encryption, as is done in\r\n OSI message handling and directory service protocols, then\r\n Layer 6 functions must be replicated in Layer 7. [X400, X500].\r\nShirey Informational [Page 163]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n The two models are most alike at the top of OSIRM Layer 3, where\r\n the OSI Connectionless Network Layer Protocol (CLNP) and the IPS\r\n IP are quite similar. Connection-oriented security services\r\n offered in OSIRM Layer 3 are inapplicable in the IPS, because the\r\n IPS Internet Layer lacks the explicit, connection-oriented service\r\n offered in the OSIRM.\r\n $ Internet Security Association and Key Management Protocol (ISAKMP)\r\n (I) An Internet IPsec protocol [R2408] to negotiate, establish,\r\n modify, and delete security associations, and to exchange key\r\n generation and authentication data, independent of the details of\r\n any specific key generation technique, key establishment protocol,\r\n encryption algorithm, or authentication mechanism.\r\n Tutorial: ISAKMP supports negotiation of security associations for\r\n protocols at all IPS layers. By centralizing management of\r\n security associations, ISAKMP reduces duplicated functionality\r\n within each protocol. ISAKMP can also reduce connection setup\r\n time, by negotiating a whole stack of services at once. Strong\r\n authentication is required on ISAKMP exchanges, and a digital\r\n signature algorithm based on asymmetric cryptography is used\r\n within ISAKMP's authentication component.\r\n ISAKMP negotiations are conducted in two \"phases\":\r\n - \"Phase 1 negotiation\". A phase 1 negotiation establishes a\r\n security association to be used by ISAKMP to protect its own\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 195 of 436\n\nprotocol operations.\r\n - \"Phase 2 negotiation\". A phase 2 negotiation (which is\r\n protected by a security association that was established by a\r\n phase 1 negotiation) establishes a security association to be\r\n used to protect the operations of a protocol other than ISAKMP,\r\n such as ESP.\r\n $ Internet Society (ISOC)\r\n (I) A professional society concerned with Internet development\r\n (including technical Internet Standards); with how the Internet is\r\n and can be used; and with social, political, and technical issues\r\n that result. The ISOC Board of Trustees approves appointments to\r\n the IAB from among nominees submitted by the IETF nominating\r\n committee. (RFC 2026)\r\n $ Internet Standard\r\n (I) A specification, approved by the IESG and published as an RFC,\r\n that is stable and well-understood, is technically competent, has\r\n multiple, independent, and interoperable implementations with\r\n substantial operational experience, enjoys significant public\r\n support, and is recognizably useful in some or all parts of the\r\n Internet. (RFC 2026) (Compare: RFC.)\r\nShirey Informational [Page 164]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: The \"Internet Standards Process\" is an activity of the\r\n ISOC and is organized and managed by the IAB and the IESG. The\r\n process is concerned with all protocols, procedures, and\r\n conventions used in or by the Internet, whether or not they are\r\n part of the IPS. The \"Internet Standards Track\" has three levels\r\n of increasing maturity: Proposed Standard, Draft Standard, and\r\n Standard. (Compare: ISO, W3C.)\r\n $ internetwork\r\n (I) A system of interconnected networks; a network of networks.\r\n Usually shortened to \"internet\". (See: internet, Internet.)\r\n Tutorial: An internet can be built using OSIRM Layer 3 gateways to\r\n implement connections between a set of similar subnetworks. With\r\n dissimilar subnetworks, i.e., subnetworks that differ in the Layer\r\n 3 protocol service they offer, an internet can be built by\r\n implementing a uniform internetwork protocol (e.g., IP) that\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 196 of 436\n\noperates at the top of Layer 3 and hides the underlying\r\n subnetworks' heterogeneity from hosts that use communication\r\n services provided by the internet. (See: router.)\r\n $ intranet\r\n (I) A computer network, especially one based on Internet\r\n technology, that an organization uses for its own internal (and\r\n usually private) purposes and that is closed to outsiders. (See:\r\n extranet, VPN.)\r\n $ intruder\r\n (I) An entity that gains or attempts to gain access to a system or\r\n system resource without having authorization to do so. (See:\r\n intrusion. Compare: adversary, cracker, hacker.)\r\n $ intrusion\r\n 1. (I) A security event, or a combination of multiple security\r\n events, that constitutes a security incident in which an intruder\r\n gains, or attempts to gain, access to a system or system resource\r\n without having authorization to do so. (See: IDS.)\r\n 2. (I) A type of threat action whereby an unauthorized entity\r\n gains access to sensitive data by circumventing a system's\r\n security protections. (See: unauthorized disclosure.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Trespass\": Gaining physical access to sensitive data by\r\n circumventing a system's protections.\r\n - \"Penetration\": Gaining logical access to sensitive data by\r\n circumventing a system's protections.\r\nShirey Informational [Page 165]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - \"Reverse engineering\": Acquiring sensitive data by\r\n disassembling and analyzing the design of a system component.\r\n - \"Cryptanalysis\": Transforming encrypted data into plain text\r\n without having prior knowledge of encryption parameters or\r\n processes. (See: main entry for \"cryptanalysis\".)\r\n $ intrusion detection\r\n (I) Sensing and analyzing system events for the purpose of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 197 of 436\n\nnoticing (i.e., becoming aware of) attempts to access system\r\n resources in an unauthorized manner. (See: anomaly detection, IDS,\r\n misuse detection. Compare: extrusion detection.) [IDSAN, IDSSC,\r\n IDSSE, IDSSY]\r\n Usage: This includes the following subtypes:\r\n - \"Active detection\": Real-time or near-real-time analysis of\r\n system event data to detect current intrusions, which result in\r\n an immediate protective response.\r\n - \"Passive detection\": Off-line analysis of audit data to detect\r\n past intrusions, which are reported to the system security\r\n officer for corrective action. (Compare: security audit.)\r\n $ intrusion detection system (IDS)\r\n 1. (N) A process or subsystem, implemented in software or\r\n hardware, that automates the tasks of (a) monitoring events that\r\n occur in a computer network and (b) analyzing them for signs of\r\n security problems. [SP31] (See: intrusion detection.)\r\n 2. (N) A security alarm system to detect unauthorized entry.\r\n [DC6/9].\r\n Tutorial: Active intrusion detection processes can be either host-\r\n based or network-based:\r\n - \"Host-based\": Intrusion detection components -- traffic sensors\r\n and analyzers -- run directly on the hosts that they are\r\n intended to protect.\r\n - \"Network-based\": Sensors are placed on subnetwork components,\r\n and analysis components run either on subnetwork components or\r\n hosts.\r\n $ invalidity date\r\n (N) An X.509 CRL entry extension that \"indicates the date at which\r\n it is known or suspected that the [revoked certificate's private\r\n key] was compromised or that the certificate should otherwise be\r\n considered invalid.\" [X509].\r\n Tutorial: This date may be earlier than the revocation date in the\r\n CRL entry, and may even be earlier than the date of issue of\r\n earlier CRLs. However, the invalidity date is not, by itself,\r\nShirey Informational [Page 166]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 198 of 436\n\nsufficient for purposes of non-repudiation service. For example,\r\n to fraudulently repudiate a validly generated signature, a private\r\n key holder may falsely claim that the key was compromised at some\r\n time in the past.\r\n $ IOTP\r\n (I) See: Internet Open Trading Protocol.\r\n $ IP\r\n (I) See: Internet Protocol.\r\n $ IP address\r\n (I) A computer's internetwork address that is assigned for use by\r\n IP and other protocols.\r\n Tutorial: An IP version 4 address (RFC 791) has four 8-bit parts\r\n and is written as a series of four decimal numbers separated by\r\n periods. Example: The address of the host named \"rosslyn.bbn.com\"\r\n is 192.1.7.10.\r\n An IP version 6 address (RFC 2373) has eight 16-bit parts and is\r\n written as eight hexadecimal numbers separated by colons.\r\n Examples: 1080:0:0:0:8:800:200C:417A and\r\n FEDC:BA98:7654:3210:FEDC:BA98:7654:3210.\r\n $ IP Security Option\r\n (I) See: Internet Protocol Security Option.\r\n $ IP Security Protocol (IPsec)\r\n 1a. (I) The name of the IETF working group that is specifying an\r\n architecture [R2401, R4301] and set of protocols to provide\r\n security services for IP traffic. (See: AH, ESP, IKE, SAD, SPD.\r\n Compare: IPSO.)\r\n 1b. (I) A collective name for the IP security architecture [R4301]\r\n and associated set of protocols (primarily AH, ESP, and IKE).\r\n Usage: In IDOCs that use the abbreviation \"IPsec\", the letters\r\n \"IP\" SHOULD be in uppercase, and the letters \"sec\" SHOULD NOT.\r\n Tutorial: The security services provided by IPsec include access\r\n control service, connectionless data integrity service, data\r\n origin authentication service, protection against replays\r\n (detection of the arrival of duplicate datagrams, within a\r\n constrained window), data confidentiality service, and limited\r\n traffic-flow confidentiality. IPsec specifies (a) security\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 199 of 436\n\nprotocols (AH and ESP), (b) security associations (what they are,\r\n how they work, how they are managed, and associated processing),\r\nShirey Informational [Page 167]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n (c) key management (IKE), and (d) algorithms for authentication\r\n and encryption. Implementation of IPsec is optional for IP version\r\n 4, but mandatory for IP version 6. (See: transport mode, tunnel\r\n mode.)\r\n $ IPLI\r\n (I) See: Internet Private Line Interface.\r\n $ IPRA\r\n (I) See: Internet Policy Registration Authority.\r\n $ IPS\r\n (I) See: Internet Protocol Suite.\r\n $ IPsec\r\n (I) See: IP Security Protocol.\r\n $ IPSO\r\n (I) See: Internet Protocol Security Option.\r\n $ ISAKMP\r\n (I) See: Internet Security Association and Key Management\r\n Protocol.\r\n $ ISO\r\n (I) International Organization for Standardization, a voluntary,\r\n non-treaty, non-governmental organization, established in 1947,\r\n with voting members that are designated standards bodies of\r\n participating nations and non-voting observer organizations.\r\n (Compare: ANSI, IETF, ITU-T, W3C.)\r\n Tutorial: Legally, ISO is a Swiss, non-profit, private\r\n organization. ISO and the IEC (the International Electrotechnical\r\n Commission) form the specialized system for worldwide\r\n standardization. National bodies that are members of ISO or IEC\r\n participate in developing international standards through ISO and\r\n IEC technical committees that deal with particular fields of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 200 of 436\n\nactivity. Other international governmental and non-governmental\r\n organizations, in liaison with ISO and IEC, also take part. (ANSI\r\n is the U.S. voting member of ISO. ISO is a class D member of ITU-\r\n T.)\r\n The ISO standards development process has four levels of\r\n increasing maturity: Working Draft (WD), Committee Draft (CD),\r\n Draft International Standard (DIS), and International Standard\r\n (IS). (Compare: \"Internet Standards Track\" under \"Internet\r\n Standard\".) In information technology, ISO and IEC have a joint\r\n technical committee, ISO/IEC JTC 1. DISs adopted by JTC 1 are\r\nShirey Informational [Page 168]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n circulated to national bodies for voting, and publication as an IS\r\n requires approval by at least 75% of the national bodies casting a\r\n vote.\r\n $ ISO 17799\r\n (N) An International Standard that is a code of practice, derived\r\n from Part 1 of British Standard 7799, for managing the security of\r\n information systems in an organization. This standard does not\r\n provide definitive or specific material on any security topic. It\r\n provides general guidance on a wide variety of topics, but\r\n typically does not go into depth. (See: IATF, [SP14].)\r\n $ ISOC\r\n (I) See: Internet Society.\r\n $ issue\r\n (I) /PKI/ Generate and sign a digital certificate (or a CRL) and,\r\n usually, distribute it and make it available to potential\r\n certificate users (or CRL users). (See: certificate creation.)\r\n Usage: The term \"issuing\" is usually understood to refer not only\r\n to creating a digital certificate (or a CRL) but also to making it\r\n available to potential users, such as by storing it in a\r\n repository or other directory or otherwise publishing it. However,\r\n the ABA [DSG] explicitly limits this term to the creation process\r\n and excludes any related publishing or distribution process.\r\n $ issuer\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 201 of 436\n\n1. (I) /certificate, CRL/ The CA that signs a digital certificate\r\n or CRL.\r\n Tutorial: An X.509 certificate always includes the issuer's name.\r\n The name may include a common name value.\r\n 2. (O) /payment card, SET/ \"The financial institution or its agent\r\n that issues the unique primary account number to the cardholder\r\n for the payment card brand.\" [SET2]\r\n Tutorial: The institution that establishes the account for a\r\n cardholder and issues the payment card also guarantees payment for\r\n authorized transactions that use the card in accordance with card\r\n brand regulations and local legislation. [SET1]\r\n $ ITAR\r\n (O) See: International Traffic in Arms Regulations.\r\n $ ITSEC\r\n (N) See: Information Technology System Evaluation Criteria.\r\nShirey Informational [Page 169]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ ITU-T\r\n (N) International Telecommunications Union, Telecommunication\r\n Standardization Sector (formerly \"CCITT\"), a United Nations treaty\r\n organization that is composed mainly of postal, telephone, and\r\n telegraph authorities of the member countries and that publishes\r\n standards called \"Recommendations\". (See: X.400, X.500.)\r\n Tutorial: The Department of State represents the United States.\r\n ITU-T works on many kinds of communication systems. ITU-T\r\n cooperates with ISO on communication protocol standards, and many\r\n Recommendations in that area are also published as an ISO standard\r\n with an ISO name and number.\r\n $ IV\r\n (I) See: initialization value.\r\n $ jamming\r\n (N) An attack that attempts to interfere with the reception of\r\n broadcast communications. (See: anti-jam, denial of service.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 202 of 436\n\nCompare: flooding.)\r\n Tutorial: Jamming uses \"interference\" as a type of \"obstruction\"\r\n intended to cause \"disruption\". Jamming a broadcast signal is\r\n typically done by broadcasting a second signal that receivers\r\n cannot separate from the first one. Jamming is mainly thought of\r\n in the context of wireless communication, but also can be done in\r\n some wired technologies, such as LANs that use contention\r\n techniques to share a broadcast medium.\r\n $ KAK\r\n (D) See: key-auto-key. (Compare: KEK.)\r\n $ KDC\r\n (I) See: Key Distribution Center.\r\n $ KEA\r\n (N) See: Key Exchange Algorithm.\r\n $ KEK\r\n (I) See: key-encrypting key. (Compare: KAK.)\r\n $ Kerberos\r\n (I) A system developed at the Massachusetts Institute of\r\n Technology that depends on passwords and symmetric cryptography\r\n (DES) to implement ticket-based, peer entity authentication\r\n service and access control service distributed in a client-server\r\n network environment. [R4120, Stei] (See: realm.)\r\nShirey Informational [Page 170]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Kerberos was originally developed by Project Athena and\r\n is named for the mythical three-headed dog that guards Hades. The\r\n system architecture includes authentication servers and ticket-\r\n granting servers that function as an ACC and a KDC.\r\n RFC 4556 describes extensions to the Kerberos specification that\r\n modify the initial authentication exchange between a client and\r\n the KDC. The extensions employ public-key cryptography to enable\r\n the client and KDC to mutually authenticate and establish shared,\r\n symmetric keys that are used to complete the exchange. (See:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 203 of 436\n\nPKINIT.)\r\n $ kernel\r\n (I) A small, trusted part of a system that provides services on\r\n which the other parts of the system depend. (See: security\r\n kernel.)\r\n $ Kernelized Secure Operating System (KSOS)\r\n (O) An MLS computer operating system, designed to be a provably\r\n secure replacement for UNIX Version 6, and consisting of a\r\n security kernel, non-kernel security-related utility programs, and\r\n optional UNIX application development and support environments.\r\n [Perr]\r\n Tutorial: KSOS-6 was the implementation on a SCOMP. KSOS-11 was\r\n the implementation by Ford Aerospace and Communications\r\n Corporation on the DEC PDP-11/45 and PDP-11/70 computers.\r\n $ key\r\n 1a. (I) /cryptography/ An input parameter used to vary a\r\n transformation function performed by a cryptographic algorithm.\r\n (See: private key, public key, storage key, symmetric key, traffic\r\n key. Compare: initialization value.)\r\n 1b. (O) /cryptography/ Used in singular form as a collective noun\r\n referring to keys or keying material. Example: A fill device can\r\n be used transfer key between two cryptographic devices.\r\n 2. (I) /anti-jam/ An input parameter used to vary a process that\r\n determines patterns for an anti-jam measure. (See: frequency\r\n hopping, spread spectrum.)\r\n Tutorial: A key is usually specified as a sequence of bits or\r\n other symbols. If a key value needs to be kept secret, the\r\n sequence of symbols that comprise it should be random, or at least\r\n pseudorandom, because that makes the key harder for an adversary\r\n to guess. (See: brute-force attack, cryptanalysis, strength.)\r\nShirey Informational [Page 171]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ key agreement (algorithm or protocol)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 204 of 436\n\n1. (I) A key establishment method (especially one involving\r\n asymmetric cryptography) by which two or more entities, without\r\n prior arrangement except a public exchange of data (such as public\r\n keys), each can generate the same key value. That is, the method\r\n does not send a secret from one entity to the other; instead, both\r\n entities, without prior arrangement except a public exchange of\r\n data, can compute the same secret value, but that value cannot be\r\n computed by other, unauthorized entities. (See: Diffie-Hellman-\r\n Merkle, key establishment, KEA, MQV. Compare: key transport.)\r\n 2. (O) \"A method for negotiating a key value on line without\r\n transferring the key, even in an encrypted form, e.g., the Diffie-\r\n Hellman technique.\" [X509] (See: Diffie-Hellman-Merkle.)\r\n 3. (O) \"The procedure whereby two different parties generate\r\n shared symmetric keys such that any of the shared symmetric keys\r\n is a function of the information contributed by all legitimate\r\n participants, so that no party [alone] can predetermine the value\r\n of the key.\" [A9042]\r\n Example: A message originator and the intended recipient can each\r\n use their own private key and the other's public key with the\r\n Diffie-Hellman-Merkle algorithm to first compute a shared secret\r\n value and, from that value, derive a session key to encrypt the\r\n message.\r\n $ key authentication\r\n (N) \"The assurance of the legitimate participants in a key\r\n agreement [i.e., in a key-agreement protocol] that no non-\r\n legitimate party possesses the shared symmetric key.\" [A9042]\r\n $ key-auto-key (KAK)\r\n (D) \"Cryptographic logic [i.e., a mode of operation] using\r\n previous key to produce key.\" [C4009, A1523] (See: CTAK,\r\n /cryptographic operation/ under \"mode\".)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is neither\r\n well-known nor precisely defined. Instead, use terms associated\r\n with modes that are defined in standards, such as CBC, CFB, and\r\n OFB.\r\n $ key center\r\n (I) A centralized, key-distribution process (used in symmetric\r\n cryptography), usually a separate computer system, that uses\r\n master keys (i.e., KEKs) to encrypt and distribute session keys\r\n needed by a community of users.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 205 of 436\n\nShirey Informational [Page 172]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: An ANSI standard [A9017] defines two types of key\r\n center: \"key distribution center\" and \"key translation center\".\r\n $ key confirmation\r\n (N) \"The assurance [provided to] the legitimate participants in a\r\n key establishment protocol that the [parties that are intended to\r\n share] the symmetric key actually possess the shared symmetric\r\n key.\" [A9042]\r\n $ key distribution\r\n (I) A process that delivers a cryptographic key from the location\r\n where it is generated to the locations where it is used in a\r\n cryptographic algorithm. (See: key establishment, key management.)\r\n $ key distribution center (KDC)\r\n 1. (I) A type of key center (used in symmetric cryptography) that\r\n implements a key-distribution protocol to provide keys (usually,\r\n session keys) to two (or more) entities that wish to communicate\r\n securely. (Compare: key translation center.)\r\n 2. (N) \"COMSEC facility generating and distributing key in\r\n electrical form.\" [C4009]\r\n Tutorial: A KDC distributes keys to Alice and Bob, who (a) wish to\r\n communicate with each other but do not currently share keys, (b)\r\n each share a KEK with the KDC, and (c) may not be able to generate\r\n or acquire keys by themselves. Alice requests the keys from the\r\n KDC. The KDC generates or acquires the keys and makes two\r\n identical sets. The KDC encrypts one set in the KEK it shares with\r\n Alice, and sends that encrypted set to Alice. The KDC encrypts the\r\n second set in the KEK it shares with Bob, and either (a) sends\r\n that encrypted set to Alice for her to forward to Bob or (b) sends\r\n it directly to Bob (although the latter option is not supported in\r\n the ANSI standard [A9017]).\r\n $ key encapsulation\r\n (N) A key recovery technique for storing knowledge of a\r\n cryptographic key by encrypting it with another key and ensuring\r\n that only certain third parties called \"recovery agents\" can\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 206 of 436\n\nperform the decryption operation to retrieve the stored key. Key\r\n encapsulation typically permits direct retrieval of a secret key\r\n used to provide data confidentiality. (Compare: key escrow.)\r\n $ key-encrypting key (KEK)\r\n (I) A cryptographic key that (a) is used to encrypt other keys\r\n (either DEKs or other TEKs) for transmission or storage but (b)\r\n (usually) is not used to encrypt application data. Usage:\r\n Sometimes called \"key-encryption key\".\r\nShirey Informational [Page 173]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ key escrow\r\n (N) A key recovery technique for storing knowledge of a\r\n cryptographic key or parts thereof in the custody of one or more\r\n third parties called \"escrow agents\", so that the key can be\r\n recovered and used in specified circumstances. (Compare: key\r\n encapsulation.)\r\n Tutorial: Key escrow is typically implemented with split knowledge\r\n techniques. For example, the Escrowed Encryption Standard [FP185]\r\n entrusts two components of a device-unique split key to separate\r\n escrow agents. The agents provide the components only to someone\r\n legally authorized to conduct electronic surveillance of\r\n telecommunications encrypted by that specific device. The\r\n components are used to reconstruct the device-unique key, and it\r\n is used to obtain the session key needed to decrypt\r\n communications.\r\n $ key establishment (algorithm or protocol)\r\n 1. (I) A procedure that combines the key-generation and key-\r\n distribution steps needed to set up or install a secure\r\n communication association.\r\n 2. (I) A procedure that results in keying material being shared\r\n among two or more system entities. [A9042, SP56]\r\n Tutorial: The two basic techniques for key establishment are \"key\r\n agreement\" and \"key transport\".\r\n $ Key Exchange Algorithm (KEA)\r\n (N) A key-agreement method [SKIP, R2773] that is based on the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 207 of 436\n\nDiffie-Hellman-Merkle algorithm and uses 1024-bit asymmetric keys.\r\n (See: CAPSTONE, CLIPPER, FORTEZZA, SKIPJACK.)\r\n Tutorial: KEA was developed by NSA and formerly classified at the\r\n U.S. DoD \"Secret\" level. On 23 June 1998, the NSA announced that\r\n KEA had been declassified.\r\n $ key generation\r\n (I) A process that creates the sequence of symbols that comprise a\r\n cryptographic key. (See: key management.)\r\n $ key generator\r\n 1. (I) An algorithm that uses mathematical rules to\r\n deterministically produce a pseudorandom sequence of cryptographic\r\n key values.\r\n 2. (I) An encryption device that incorporates a key-generation\r\n mechanism and applies the key to plain text to produce cipher text\r\nShirey Informational [Page 174]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n (e.g., by exclusive OR-ing (a) a bit-string representation of the\r\n key with (b) a bit-string representation of the plaintext).\r\n $ key length\r\n (I) The number of symbols (usually stated as a number of bits)\r\n needed to be able to represent any of the possible values of a\r\n cryptographic key. (See: key space.)\r\n $ key lifetime\r\n 1. (D) Synonym for \"cryptoperiod\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 1 because a key's cryptoperiod may be only a part of\r\n the key's lifetime. A key could be generated at some time prior to\r\n when its cryptoperiod begins and might not be destroyed (i.e.,\r\n zeroized) until some time after its cryptoperiod ends.\r\n 2. (O) /MISSI/ An attribute of a MISSI key pair that specifies a\r\n time span that bounds the validity period of any MISSI X.509\r\n public-key certificate that contains the public component of the\r\n pair. (See: cryptoperiod.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 208 of 436\n\n$ key loader\r\n (N) Synonym for \"fill device\".\r\n $ key loading and initialization facility (KLIF)\r\n (N) A place where ECU hardware is activated after being\r\n fabricated. (Compare: CLEF.)\r\n Tutorial: Before going to its KLIF, an ECU is not ready to be\r\n fielded, usually because it is not yet able to receive DEKs. The\r\n KLIF employs trusted processes to complete the ECU by installing\r\n needed data such as KEKs, seed values, and, in some cases,\r\n cryptographic software. After KLIF processing, the ECU is ready\r\n for deployment.\r\n $ key management\r\n 1a. (I) The process of handling keying material during its life\r\n cycle in a cryptographic system; and the supervision and control\r\n of that process. (See: key distribution, key escrow, keying\r\n material, public-key infrastructure.)\r\n Usage: Usually understood to include ordering, generating,\r\n storing, archiving, escrowing, distributing, loading, destroying,\r\n auditing, and accounting for the material.\r\n 1b. (O) /NIST/ \"The activities involving the handling of\r\n cryptographic keys and other related security parameters (e.g.,\r\nShirey Informational [Page 175]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n IVs, counters) during the entire life cycle of the keys, including\r\n their generation, storage, distribution, entry and use, deletion\r\n or destruction, and archiving.\" [FP140, SP57]\r\n 2. (O) /OSIRM/ \"The generation, storage, distribution, deletion,\r\n archiving and application of keys in accordance with a security\r\n policy.\" [I7498-2]\r\n $ Key Management Protocol (KMP)\r\n (N) A protocol to establish a shared symmetric key between a pair\r\n (or a group) of users. (One version of KMP was developed by SDNS,\r\n and another by SILS.) Superseded by ISAKMP and IKE.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 209 of 436\n\n$ key material\r\n (D) Synonym for \"keying material\".\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n \"keying material\".\r\n $ key pair\r\n (I) A set of mathematically related keys -- a public key and a\r\n private key -- that are used for asymmetric cryptography and are\r\n generated in a way that makes it computationally infeasible to\r\n derive the private key from knowledge of the public key. (See:\r\n Diffie-Hellman-Merkle, RSA.)\r\n Tutorial: A key pair's owner discloses the public key to other\r\n system entities so they can use the key to (a) encrypt data, (b)\r\n verify a digital signature, or (c) generate a key with a key-\r\n agreement algorithm. The matching private key is kept secret by\r\n the owner, who uses it to (a') decrypt data, (b') generate a\r\n digital signature, or (c') generate a key with a key-agreement\r\n algorithm.\r\n $ key recovery\r\n 1. (I) /cryptanalysis/ A process for learning the value of a\r\n cryptographic key that was previously used to perform some\r\n cryptographic operation. (See: cryptanalysis, recovery.)\r\n 2. (I) /backup/ Techniques that provide an intentional, alternate\r\n means to access the key used for data confidentiality service in\r\n an encrypted association. [DoD4] (Compare: recovery.)\r\n Tutorial: It is assumed that the cryptographic system includes a\r\n primary means of obtaining the key through a key-establishment\r\n algorithm or protocol. For the secondary means, there are two\r\n classes of key recovery techniques: key encapsulation and key\r\n escrow.\r\nShirey Informational [Page 176]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ key space\r\n (I) The range of possible values of a cryptographic key; or the\r\n number of distinct transformations supported by a particular\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 210 of 436\n\ncryptographic algorithm. (See: key length.)\r\n $ key translation center\r\n (I) A type of key center that implements a key-distribution\r\n protocol (based on symmetric cryptography) to convey keys between\r\n two (or more) parties who wish to communicate securely. (Compare:\r\n key distribution center.)\r\n Tutorial: A key translation center transfers keys for future\r\n communication between Bob and Alice, who (a) wish to communicate\r\n with each other but do not currently share keys, (b) each share a\r\n KEK with the center, and (c) have the ability to generate or\r\n acquire keys by themselves. Alice generates or acquires a set of\r\n keys for communication with Bob. Alice encrypts the set in the KEK\r\n she shares with the center and sends the encrypted set to the\r\n center. The center decrypts the set, reencrypts the set in the KEK\r\n it shares with Bob, and either (a) sends that reencrypted set to\r\n Alice for her to forward to Bob or (b) sends it directly to Bob\r\n (although direct distribution is not supported in the ANSI\r\n standard [A9017]).\r\n $ key transport (algorithm or protocol)\r\n 1. (I) A key establishment method by which a secret key is\r\n generated by a system entity in a communication association and\r\n securely sent to another entity in the association. (Compare: key\r\n agreement.)\r\n Tutorial: Either (a) one entity generates a secret key and\r\n securely sends it to the other entity, or (b) each entity\r\n generates a secret value and securely sends it to the other\r\n entity, where the two values are combined to form a secret key.\r\n For example, a message originator can generate a random session\r\n key and then use the RSA algorithm to encrypt that key with the\r\n public key of the intended recipient.\r\n 2. (O) \"The procedure to send a symmetric key from one party to\r\n other parties. As a result, all legitimate participants share a\r\n common symmetric key in such a way that the symmetric key is\r\n determined entirely by one party.\" [A9042]\r\n $ key update\r\n 1. (I) Derive a new key from an existing key. (Compare: rekey.)\r\n 2. (O) Irreversible cryptographic process that modifies a key to\r\n produce a new key. [C4009]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 211 of 436\n\nShirey Informational [Page 177]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ key validation\r\n 1. (I) \"The procedure for the receiver of a public key to check\r\n that the key conforms to the arithmetic requirements for such a\r\n key in order to thwart certain types of attacks.\" [A9042] (See:\r\n weak key)\r\n 2. (D) Synonym for \"certificate validation\".\r\n Deprecated Usage: IDOCs SHOULD NOT use the term as a synonym for\r\n \"certificate validation\"; that would unnecessarily duplicate the\r\n meaning of the latter term and mix concepts in a potentially\r\n misleading way. In validating an X.509 public-key certificate, the\r\n public key contained in the certificate is normally treated as an\r\n opaque data object.\r\n $ keyed hash\r\n (I) A cryptographic hash (e.g., [R1828]) in which the mapping to a\r\n hash result is varied by a second input parameter that is a\r\n cryptographic key. (See: checksum.)\r\n Tutorial: If the input data object is changed, a new,\r\n corresponding hash result cannot be correctly computed without\r\n knowledge of the secret key. Thus, the secret key protects the\r\n hash result so it can be used as a checksum even when there is a\r\n threat of an active attack on the data. There are two basic types\r\n of keyed hash:\r\n - A function based on a keyed encryption algorithm. Example: Data\r\n Authentication Code.\r\n - A function based on a keyless hash that is enhanced by\r\n combining (e.g., by concatenating) the input data object\r\n parameter with a key parameter before mapping to the hash\r\n result. Example: HMAC.\r\n $ keying material\r\n 1. (I) Data that is needed to establish and maintain a\r\n cryptographic security association, such as keys, key pairs, and\r\n IVs.\r\n 2. (O) \"Key, code, or authentication information in physical or\r\n magnetic form.\" [C4009] (Compare: COMSEC material.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 212 of 436\n\n$ keying material identifier (KMID)\r\n 1. (I) An identifier assigned to an item of keying material.\r\n 2. (O) /MISSI/ A 64-bit identifier that is assigned to a key pair\r\n when the public key is bound in a MISSI X.509 public-key\r\n certificate.\r\nShirey Informational [Page 178]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Khafre\r\n (N) A patented, symmetric block cipher designed by Ralph C. Merkle\r\n as a plug-in replacement for DES. [Schn]\r\n Tutorial: Khafre was designed for efficient encryption of small\r\n amounts of data. However, because Khafre does not precompute\r\n tables used for encryption, it is slower than Khufu for large\r\n amounts of data.\r\n $ Khufu\r\n (N) A patented, symmetric block cipher designed by Ralph C. Merkle\r\n as a plug-in replacement for DES. [Schn]\r\n Tutorial: Khufu was designed for fast encryption of large amounts\r\n of data. However, because Khufu precomputes tables used in\r\n encryption, it is less efficient than Khafre for small amounts of\r\n data.\r\n $ KLIF\r\n (N) See: key loading and initialization facility.\r\n $ KMID\r\n (I) See: keying material identifier.\r\n $ known-plaintext attack\r\n (I) A cryptanalysis technique in which the analyst tries to\r\n determine the key from knowledge of some plaintext-ciphertext\r\n pairs (although the analyst may also have other clues, such as\r\n knowing the cryptographic algorithm).\r\n $ kracker\r\n (O) Old spelling for \"cracker\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 213 of 436\n\n$ KSOS, KSOS-6, KSOS-11\r\n (O) See: Kernelized Secure Operating System.\r\n $ L2F\r\n (N) See: Layer 2 Forwarding Protocol.\r\n $ L2TP\r\n (N) See: Layer 2 Tunneling Protocol.\r\n $ label\r\n See: time stamp, security label.\r\nShirey Informational [Page 179]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ laboratory attack\r\n (O) \"Use of sophisticated signal recovery equipment in a\r\n laboratory environment to recover information from data storage\r\n media.\" [C4009]\r\n $ LAN\r\n (I) Abbreviation for \"local area network\" [R1983]. (See: [FP191].)\r\n $ land attack\r\n (I) A denial-of-service attack that sends an IP packet that (a)\r\n has the same address in both the Source Address and Destination\r\n Address fields and (b) contains a TCP SYN packet that has the same\r\n port number in both the Source Port and Destination Port fields.\r\n Derivation: This single-packet attack was named for \"land\", the\r\n program originally published by the cracker who invented this\r\n exploit. Perhaps that name was chosen because the inventor thought\r\n of multi-packet (i.e., flooding) attacks as arriving by sea.\r\n $ Language of Temporal Ordering Specification (LOTOS)\r\n (N) A language (ISO 8807-1990) for formal specification of\r\n computer network protocols; describes the order in which events\r\n occur.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 214 of 436\n\n$ lattice\r\n (I) A finite set together with a partial ordering on its elements\r\n such that for every pair of elements there is a least upper bound\r\n and a greatest lower bound.\r\n Example: A lattice is formed by a finite set S of security levels\r\n -- i.e., a set S of all ordered pairs (x,c), where x is one of a\r\n finite set X of hierarchically ordered classification levels X(1),\r\n non-hierarchical categories C(1), ..., C(M) -- together with the\r\n \"dominate\" relation. Security level (x,c) is said to \"dominate\"\r\n (x',c') if and only if (a) x is greater (higher) than or equal to\r\n x' and (b) c includes at least all of the elements of c'. (See:\r\n dominate, lattice model.)\r\n Tutorial: Lattices are used in some branches of cryptography, both\r\n as a basis for hard computational problems upon which\r\n cryptographic algorithms can be defined, and also as a basis for\r\n attacks on cryptographic algorithms.\r\n $ lattice model\r\n 1. (I) A description of the semantic structure formed by a finite\r\n set of security levels, such as those used in military\r\n organizations. (See: dominate, lattice, security model.)\r\nShirey Informational [Page 180]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /formal model/ A model for flow control in a system, based\r\n on the lattice that is formed by the finite security levels in a\r\n system and their partial ordering. [Denn]\r\n $ Law Enforcement Access Field (LEAF)\r\n (N) A data item that is automatically embedded in data encrypted\r\n by devices (e.g., CLIPPER chip) that implement the Escrowed\r\n Encryption Standard.\r\n $ Layer 1, 2, 3, 4, 5, 6, 7\r\n (N) See: OSIRM.\r\n $ Layer 2 Forwarding Protocol (L2F)\r\n (N) An Internet protocol (originally developed by Cisco\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 215 of 436\n\nCorporation) that uses tunneling of PPP over IP to create a\r\n virtual extension of a dial-up link across a network, initiated by\r\n the dial-up server and transparent to the dial-up user. (See:\r\n L2TP.)\r\n $ Layer 2 Tunneling Protocol (L2TP)\r\n (N) An Internet client-server protocol that combines aspects of\r\n PPTP and L2F and supports tunneling of PPP over an IP network or\r\n over frame relay or other switched network. (See: VPN.)\r\n Tutorial: PPP can in turn encapsulate any OSIRM Layer 3 protocol.\r\n Thus, L2TP does not specify security services; it depends on\r\n protocols layered above and below it to provide any needed\r\n security.\r\n $ LDAP\r\n (I) See: Lightweight Directory Access Protocol.\r\n $ least common mechanism\r\n (I) The principle that a security architecture should minimize\r\n reliance on mechanisms that are shared by many users.\r\n Tutorial: Shared mechanisms may include cross-talk paths that\r\n permit a breach of data security, and it is difficult to make a\r\n single mechanism operate in a correct and trusted manner to the\r\n satisfaction of a wide range of users.\r\n $ least privilege\r\n (I) The principle that a security architecture should be designed\r\n so that each system entity is granted the minimum system resources\r\n and authorizations that the entity needs to do its work. (Compare:\r\n economy of mechanism, least trust.)\r\nShirey Informational [Page 181]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: This principle tends to limit damage that can be caused\r\n by an accident, error, or unauthorized act. This principle also\r\n tends to reduce complexity and promote modularity, which can make\r\n certification easier and more effective. This principle is similar\r\n to the principle of protocol layering, wherein each layer provides\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 216 of 436\n\nspecific, limited communication services, and the functions in one\r\n layer are independent of those in other layers.\r\n $ least trust\r\n (I) The principle that a security architecture should be designed\r\n in a way that minimizes (a) the number of components that require\r\n trust and (b) the extent to which each component is trusted.\r\n (Compare: least privilege, trust level.)\r\n $ legacy system\r\n (I) A system that is in operation but will not be improved or\r\n expanded while a new system is being developed to supersede it.\r\n $ legal non-repudiation\r\n (I) See: secondary definition under \"non-repudiation\".\r\n $ leap of faith\r\n 1. (I) /general security/ Operating a system as though it began\r\n operation in a secure state, even though it cannot be proven that\r\n such a state was established (i.e., even though a security\r\n compromise might have occurred at or before the time when\r\n operation began).\r\n 2. (I) /COMSEC/ The initial part, i.e., the first communication\r\n step, or steps, of a protocol that is vulnerable to attack\r\n (especially a man-in-the-middle attack) during that part but, if\r\n that part is completed without being attacked, is subsequently not\r\n vulnerable in later steps (i.e., results in a secure communication\r\n association for which no man-in-the-middle attack is possible).\r\n Usage: This term is listed in English dictionaries, but their\r\n definitions are broad and can be interpreted in many ways in\r\n Internet contexts. Similarly, the definition stated here can be\r\n interpreted in several ways. Therefore, IDOCs that use this term\r\n (especially IDOCs that are protocol specifications) SHOULD state a\r\n more specific definition for it.\r\n Tutorial: In a protocol, a leap of faith typically consists of\r\n accepting a claim of peer identity, data origin, or data integrity\r\n without authenticating that claim. When a protocol includes such a\r\n step, the protocol might also be designed so that if a man-in-\r\n the-middle attack succeeds during the vulnerable first part, then\r\n the attacker must remain in the middle for all subsequent\r\nShirey Informational [Page 182]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 217 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n exchanges or else one of the legitimate parties will be able to\r\n detect the attack.\r\n $ level of concern\r\n (N) /U.S. DoD/ A rating assigned to an information system that\r\n indicates the extent to which protective measures, techniques, and\r\n procedures must be applied. (See: critical, sensitive, level of\r\n robustness.)\r\n $ level of robustness\r\n (N) /U.S. DoD/ A characterization of (a) the strength of a\r\n security function, mechanism, service, or solution and (b) the\r\n assurance (or confidence) that it is implemented and functioning.\r\n [Cons, IATF] (See: level of concern.)\r\n $ Liberty Alliance\r\n (O) An international consortium of more than 150 commercial,\r\n nonprofit, and governmental organizations that was created in 2001\r\n to address technical, business, and policy problems of identity\r\n and identity-based Web services and develop a standard for\r\n federated network identity that supports current and emerging\r\n network devices.\r\n $ Lightweight Directory Access Protocol (LDAP)\r\n (I) An Internet client-server protocol (RFC 3377) that supports\r\n basic use of the X.500 Directory (or other directory servers)\r\n without incurring the resource requirements of the full Directory\r\n Access Protocol (DAP).\r\n Tutorial: Designed for simple management and browser applications\r\n that provide simple read/write interactive directory service.\r\n Supports both simple authentication and strong authentication of\r\n the client to the directory server.\r\n $ link\r\n 1a. (I) A communication facility or physical medium that can\r\n sustain data communications between multiple network nodes, in the\r\n protocol layer immediately below IP. (RFC 3753)\r\n 1b. (I) /subnetwork/ A communication channel connecting subnetwork\r\n relays (especially one between two packet switches) that is\r\n implemented at OSIRM Layer 2. (See: link encryption.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 218 of 436\n\nTutorial: The relay computers assume that links are logically\r\n passive. If a computer at one end of a link sends a sequence of\r\n bits, the sequence simply arrives at the other end after a finite\r\n time, although some bits may have been changed either accidentally\r\n (errors) or by active wiretapping.\r\nShirey Informational [Page 183]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /World Wide Web/ See: hyperlink.\r\n $ link encryption\r\n (I) Stepwise (link-by-link) protection of data that flows between\r\n two points in a network, provided by encrypting data separately on\r\n each network link, i.e., by encrypting data when it leaves a host\r\n or subnetwork relay and decrypting when it arrives at the next\r\n host or relay. Each link may use a different key or even a\r\n different algorithm. [R1455] (Compare: end-to-end encryption.)\r\n $ liveness\r\n (I) A property of a communication association or a feature of a\r\n communication protocol that provides assurance to the recipient of\r\n data that the data is being freshly transmitted by its originator,\r\n i.e., that the data is not being replayed, by either the\r\n originator or a third party, from a previous transmission. (See:\r\n fresh, nonce, replay attack.)\r\n $ logic bomb\r\n (I) Malicious logic that activates when specified conditions are\r\n met. Usually intended to cause denial of service or otherwise\r\n damage system resources. (See: Trojan horse, virus, worm.)\r\n $ login\r\n 1a. (I) An act by which a system entity establishes a session in\r\n which the entity can use system resources. (See: principal,\r\n session.)\r\n 1b. (I) An act by which a system user has its identity\r\n authenticated by the system. (See: principal, session.)\r\n Usage: Usually understood to be accomplished by providing an\r\n identifier and matching authentication information (e.g., a\r\n password) to a security mechanism that authenticates the user's\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 219 of 436\n\nidentity; but sometimes refers to establishing a connection with a\r\n server when no authentication or specific authorization is\r\n involved.\r\n Derivation: Refers to \"log\" file, a security audit trail that\r\n records (a) security events, such as the beginning of a session,\r\n and (b) the names of the system entities that initiate events.\r\n $ long title\r\n (O) /U.S. Government/ \"Descriptive title of [an item of COMSEC\r\n material].\" [C4009] (Compare: short title.)\r\nShirey Informational [Page 184]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ low probability of detection\r\n (I) Result of TRANSEC measures used to hide or disguise a\r\n communication.\r\n $ low probability of intercept\r\n (I) Result of TRANSEC measures used to prevent interception of a\r\n communication.\r\n $ LOTOS\r\n (N) See: Language of Temporal Ordering Specification.\r\n $ MAC\r\n (N) See: mandatory access control, Message Authentication Code.\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because this abbreviation is ambiguous.\r\n $ magnetic remanence\r\n (N) Magnetic representation of residual information remaining on a\r\n magnetic medium after the medium has been cleared. [NCS25] (See:\r\n clear, degauss, purge.)\r\n $ main mode\r\n (I) See: /IKE/ under \"mode\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 220 of 436\n\n$ maintenance hook\r\n (N) \"Special instructions (trapdoors) in software allowing easy\r\n maintenance and additional feature development. Since maintenance\r\n hooks frequently allow entry into the code without the usual\r\n checks, they are a serious security risk if they are not removed\r\n prior to live implementation.\" [C4009] (See: back door.)\r\n $ malicious logic\r\n (I) Hardware, firmware, or software that is intentionally included\r\n or inserted in a system for a harmful purpose. (See: logic bomb,\r\n Trojan horse, spyware, virus, worm. Compare: secondary definitions\r\n under \"corruption\", \"incapacitation\", \"masquerade\", and \"misuse\".)\r\n $ malware\r\n (D) A contraction of \"malicious software\". (See: malicious logic.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is not listed\r\n in most dictionaries and could confuse international readers.\r\n $ MAN\r\n (I) metropolitan area network.\r\nShirey Informational [Page 185]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ man-in-the-middle attack\r\n (I) A form of active wiretapping attack in which the attacker\r\n intercepts and selectively modifies communicated data to\r\n masquerade as one or more of the entities involved in a\r\n communication association. (See: hijack attack, piggyback attack.)\r\n Tutorial: For example, suppose Alice and Bob try to establish a\r\n session key by using the Diffie-Hellman-Merkle algorithm without\r\n data origin authentication service. A \"man in the middle\" could\r\n (a) block direct communication between Alice and Bob and then (b)\r\n masquerade as Alice sending data to Bob, (c) masquerade as Bob\r\n sending data to Alice, (d) establish separate session keys with\r\n each of them, and (e) function as a clandestine proxy server\r\n between them to capture or modify sensitive information that Alice\r\n and Bob think they are sending only to each other.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 221 of 436\n\n$ manager\r\n (I) A person who controls the service configuration of a system or\r\n the functional privileges of operators and other users. (See:\r\n administrative security. Compare: operator, SSO, user.)\r\n $ mandatory access control\r\n 1. (I) An access control service that enforces a security policy\r\n based on comparing (a) security labels, which indicate how\r\n sensitive or critical system resources are, with (b) security\r\n clearances, which indicate that system entities are eligible to\r\n access certain resources. (See: discretionary access control, MAC,\r\n rule-based security policy.)\r\n Derivation: This kind of access control is called \"mandatory\"\r\n because an entity that has clearance to access a resource is not\r\n permitted, just by its own volition, to enable another entity to\r\n access that resource.\r\n 2. (O) \"A means of restricting access to objects based on the\r\n sensitivity (as represented by a label) of the information\r\n contained in the objects and the formal authorization (i.e.,\r\n clearance) of subjects to access information of such sensitivity.\"\r\n [DoD1]\r\n $ manipulation detection code\r\n (D) Synonym for \"checksum\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"checksum\"; the word \"manipulation\" implies protection against\r\n active attacks, which an ordinary checksum might not provide.\r\n Instead, if such protection is intended, use \"protected checksum\"\r\n or some particular type thereof, depending on which is meant. If\r\nShirey Informational [Page 186]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n such protection is not intended, use \"error detection code\" or\r\n some specific type of checksum that is not protected.\r\n $ marking\r\n See: time stamp, security marking.\r\n $ MARS\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 222 of 436\n\n(O) A symmetric, 128-bit block cipher with variable key length\r\n (128 to 448 bits), developed by IBM as a candidate for the AES.\r\n $ Martian\r\n (D) /slang/ A packet that arrives unexpectedly at the wrong\r\n address or on the wrong network because of incorrect routing or\r\n because it has a non-registered or ill-formed IP address. [R1208]\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ masquerade\r\n (I) A type of threat action whereby an unauthorized entity gains\r\n access to a system or performs a malicious act by illegitimately\r\n posing as an authorized entity. (See: deception.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - \"Spoof\": Attempt by an unauthorized entity to gain access to a\r\n system by posing as an authorized user.\r\n - \"Malicious logic\": In context of masquerade, any hardware,\r\n firmware, or software (e.g., Trojan horse) that appears to\r\n perform a useful or desirable function, but actually gains\r\n unauthorized access to system resources or tricks a user into\r\n executing other malicious logic. (See: corruption,\r\n incapacitation, main entry for \"malicious logic\", misuse.)\r\n $ MCA\r\n (O) See: merchant certification authority.\r\n $ MD2\r\n (N) A cryptographic hash [R1319] that produces a 128-bit hash\r\n result, was designed by Ron Rivest, and is similar to MD4 and MD5\r\n but slower.\r\n Derivation: Apparently, an abbreviation of \"message digest\", but\r\n that term is deprecated by this Glossary.\r\nShirey Informational [Page 187]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 223 of 436\n\n$ MD4\r\n (N) A cryptographic hash [R1320] that produces a 128-bit hash\r\n result and was designed by Ron Rivest. (See: Derivation under\r\n \"MD2\", SHA-1.)\r\n $ MD5\r\n (N) A cryptographic hash [R1321] that produces a 128-bit hash\r\n result and was designed by Ron Rivest to be an improved version of\r\n MD4. (See: Derivation under \"MD2\".)\r\n $ merchant\r\n (O) /SET/ \"A seller of goods, services, and/or other information\r\n who accepts payment for these items electronically.\" [SET2] A\r\n merchant may also provide electronic selling services and/or\r\n electronic delivery of items for sale. With SET, the merchant can\r\n offer its cardholders secure electronic interactions, but a\r\n merchant that accepts payment cards is required to have a\r\n relationship with an acquirer. [SET1, SET2]\r\n $ merchant certificate\r\n (O) /SET/ A public-key certificate issued to a merchant. Sometimes\r\n used to refer to a pair of such certificates where one is for\r\n digital signature use and the other is for encryption.\r\n $ merchant certification authority (MCA)\r\n (O) /SET/ A CA that issues digital certificates to merchants and\r\n is operated on behalf of a payment card brand, an acquirer, or\r\n another party according to brand rules. Acquirers verify and\r\n approve requests for merchant certificates prior to issuance by\r\n the MCA. An MCA does not issue a CRL, but does distribute CRLs\r\n issued by root CAs, brand CAs, geopolitical CAs, and payment\r\n gateway CAs. [SET2]\r\n $ mesh PKI\r\n (I) A non-hierarchical PKI architecture in which there are several\r\n trusted CAs rather than a single root. Each certificate user bases\r\n path validations on the public key of one of the trusted CAs,\r\n usually the one that issued that user's own public-key\r\n certificate. Rather than having superior-to-subordinate\r\n relationships between CAs, the relationships are peer-to-peer, and\r\n CAs issue cross-certificates to each other. (Compare: hierarchical\r\n PKI, trust-file PKI.)\r\n $ Message Authentication Code (MAC), message authentication code\r\n 1. (N) /capitalized/ A specific ANSI standard for a checksum that\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 224 of 436\n\nis computed with a keyed hash that is based on DES. [A9009] Usage:\r\n a.k.a. Data Authentication Code, which is a U.S. Government\r\n standard. [FP113] (See: MAC.)\r\nShirey Informational [Page 188]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (D) /not capitalized/ Synonym for \"error detection code\".\r\n Deprecated Term: IDOCs SHOULD NOT use the uncapitalized form\r\n \"message authentication code\". Instead, use \"checksum\", \"error\r\n detection code\", \"hash\", \"keyed hash\", \"Message Authentication\r\n Code\", or \"protected checksum\", depending on what is meant. (See:\r\n authentication code.)\r\n The uncapitalized form mixes concepts in a potentially misleading\r\n way. The word \"message\" is misleading because it implies that the\r\n mechanism is particularly suitable for or limited to electronic\r\n mail (see: Message Handling Systems). The word \"authentication\" is\r\n misleading because the mechanism primarily serves a data integrity\r\n function rather than an authentication function. The word \"code\"\r\n is misleading because it implies that either encoding or\r\n encryption is involved or that the term refers to computer\r\n software.\r\n $ message digest\r\n (D) Synonym for \"hash result\". (See: cryptographic hash.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"hash result\"; this term unnecessarily duplicates the meaning of\r\n the other, more general term and mixes concepts in a potentially\r\n misleading way. The word \"message\" is misleading because it\r\n implies that the mechanism is particularly suitable for or limited\r\n to electronic mail (see: Message Handling Systems).\r\n $ message handling system\r\n (D) Synonym for the Internet electronic mail system.\r\n Deprecated Term: IDOCs SHOULD NOT use this term, because it could\r\n be confused with Message Handling System. Instead, use \"Internet\r\n electronic mail\" or some other, more specific term.\r\n $ Message Handling System\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 225 of 436\n\n(O) An ITU-T system concept that encompasses the notion of\r\n electronic mail but defines more comprehensive OSI systems and\r\n services that enable users to exchange messages on a store-and-\r\n forward basis. (The ISO equivalent is \"Message Oriented Text\r\n Interchange System\".) (See: X.400.)\r\n $ message indicator\r\n 1. (D) /cryptographic function/ Synonym for \"initialization\r\n value\". (Compare: indicator.)\r\n 2. (D) \"Sequence of bits transmitted over a communications system\r\n for synchronizing cryptographic equipment.\" [C4009]\r\nShirey Informational [Page 189]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"initialization value\"; the term mixes concepts in a potentially\r\n misleading way. The word \"message\" is misleading because it\r\n suggests that the mechanism is specific to electronic mail. (See:\r\n Message Handling System.)\r\n $ message integrity check\r\n $ message integrity code (MIC)\r\n (D) Synonyms for some form of \"checksum\".\r\n Deprecated Term: IDOCs SHOULD NOT use these terms for any form of\r\n checksum. Instead, use \"checksum\", \"error detection code\", \"hash\",\r\n \"keyed hash\", \"Message Authentication Code\", or \"protected\r\n checksum\", depending on what is meant.\r\n These two terms mix concepts in potentially misleading ways. The\r\n word \"message\" is misleading because it suggests that the\r\n mechanism is particularly suitable for or limited to electronic\r\n mail. The word \"integrity\" is misleading because the checksum may\r\n be used to perform a data origin authentication function rather\r\n than an integrity function. The word \"code\" is misleading because\r\n it suggests either that encoding or encryption is involved or that\r\n the term refers to computer software.\r\n $ Message Security Protocol (MSP)\r\n (N) A secure message handling protocol [SDNS7] for use with X.400\r\n and Internet mail protocols. Developed by NSA's SDNS program and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 226 of 436\n\nused in the U.S. DoD's Defense Message System.\r\n $ meta-data\r\n (I) Descriptive information about a data object; i.e., data about\r\n data, or data labels that describe other data. (See: security\r\n label. Compare: metadata)\r\n Tutorial: Meta-data can serve various management purposes:\r\n - System management: File name, type, size, creation date.\r\n - Application management: Document title, version, author.\r\n - Usage management: Data categories, keywords, classifications.\r\n Meta-data can be associated with a data object in two basic ways:\r\n - Explicitly: Be part of the data object (e.g., a header field of\r\n a data file or packet) or be linked to the object.\r\n - Implicitly: Be associated with the data object because of some\r\n other, explicit attribute of the object.\r\n $ metadata, Metadata(trademark), METADATA(trademark)\r\n (D) Proprietary variants of \"meta-data\". (See: SPAM(trademark).)\r\nShirey Informational [Page 190]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Usage: IDOCs SHOULD NOT use these unhypenated forms;\r\n IDOCs SHOULD use only the uncapitalized, hyphenated \"meta-data\".\r\n The terms \"Metadata\" and \"METADATA\" are claimed as registered\r\n trademarks (numbers 1,409,260 and 2,185,504) owned by The Metadata\r\n Company, originally known as Metadata Information Partners, a\r\n company founded by Jack Myers. The status of \"metadata\" is\r\n unclear.\r\n $ MHS\r\n (N) See: message handling system.\r\n $ MIC\r\n (D) See: message integrity code.\r\n $ MIME\r\n (I) See: Multipurpose Internet Mail Extensions.\r\n $ MIME Object Security Services (MOSS)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 227 of 436\n\n(I) An Internet protocol [R1848] that applies end-to-end\r\n encryption and digital signature to MIME message content, using\r\n symmetric cryptography for encryption and asymmetric cryptography\r\n for key distribution and signature. MOSS is based on features and\r\n specifications of PEM. (See: S/MIME.)\r\n $ Minimum Interoperability Specification for PKI Components (MISPC)\r\n (N) A technical description to provide a basis for interoperation\r\n between PKI components from different vendors; consists primarily\r\n of a profile of certificate and CRL extensions and a set of\r\n transactions for PKI operation. [SP15]\r\n $ misappropriation\r\n (I) A type of threat action whereby an entity assumes unauthorized\r\n logical or physical control of a system resource. (See:\r\n usurpation.)\r\n Usage: This type of threat action includes the following subtypes:\r\n - Theft of data: Unauthorized acquisition and use of data\r\n contained in a system.\r\n - Theft of service: Unauthorized use of a system service.\r\n - Theft of functionality: Unauthorized acquisition of actual\r\n hardware, firmware, or software of a system component.\r\n $ MISPC\r\n (N) See: Minimum Interoperability Specification for PKI\r\n Components.\r\nShirey Informational [Page 191]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ MISSI\r\n (O) Multilevel Information System Security Initiative, an NSA\r\n program to encourage development of interoperable, modular\r\n products for constructing secure network information systems in\r\n support of a wide variety of U.S. Government missions. (See: MSP,\r\n SP3, SP4.)\r\n $ MISSI user\r\n (O) /MISSI/ A system entity that is the subject of one or more\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 228 of 436\n\nMISSI X.509 public-key certificates issued under a MISSI\r\n certification hierarchy. (See: personality.)\r\n Tutorial: MISSI users include both end users and the authorities\r\n that issue certificates. A MISSI user is usually a person but may\r\n be a machine or other automated process. Machines that are\r\n required to operate nonstop may be issued their own certificates\r\n to avoid downtime needed to exchange the FORTEZZA cards of machine\r\n operators at shift changes.\r\n $ mission\r\n (I) A statement of a (relatively long-term) duty or (relatively\r\n short-term) task that is assigned to an organization or system,\r\n indicates the purpose and objectives of the duty or task, and may\r\n indicate the actions to be taken to achieve it.\r\n $ mission critical\r\n (I) A condition of a system service or other system resource such\r\n that denial of access to, or lack of availability of, the resource\r\n would jeopardize a system user's ability to perform a primary\r\n mission function or would result in other serious consequences.\r\n (See: Critical. Compare: mission essential.)\r\n $ mission essential\r\n (O) /U.S. DoD/ Refers to materiel that is authorized and available\r\n to combat, combat support, combat service support, and combat\r\n readiness training forces to accomplish their assigned missions.\r\n [JP1] (Compare: mission critical.)\r\n $ misuse\r\n 1. (I) The intentional use (by authorized users) of system\r\n resources for other than authorized purposes. Example: An\r\n authorized system administrator creates an unauthorized account\r\n for a friend. (See: misuse detection.)\r\n 2. (I) A type of threat action that causes a system component to\r\n perform a function or service that is detrimental to system\r\n security. (See: usurpation.)\r\nShirey Informational [Page 192]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 229 of 436\n\nUsage: This type of threat action includes the following subtypes:\r\n - \"Tampering\": /misuse/ Deliberately altering a system's logic,\r\n data, or control information to cause the system to perform\r\n unauthorized functions or services. (See: corruption, main\r\n entry for \"tampering\".)\r\n - \"Malicious logic\": /misuse/ Any hardware, firmware, or software\r\n intentionally introduced into a system to perform or control\r\n execution of an unauthorized function or service. (See:\r\n corruption, incapacitation, main entry for \"malicious logic\",\r\n masquerade.)\r\n - \"Violation of authorizations\": Action by an entity that exceeds\r\n the entity's system privileges by executing an unauthorized\r\n function. (See: authorization.)\r\n $ misuse detection\r\n (I) An intrusion detection method that is based on rules that\r\n specify system events, sequences of events, or observable\r\n properties of a system that are believed to be symptomatic of\r\n security incidents. (See: IDS, misuse. Compare: anomaly\r\n detection.)\r\n $ MLS\r\n (I) See: multilevel secure\r\n $ mobile code\r\n 1a. (I) Software that originates from a remote server, is\r\n transmitted across a network, and is loaded onto and executed on a\r\n local client system without explicit initiation by the client's\r\n user and, in some cases, without that user's knowledge. (Compare:\r\n active content.)\r\n Tutorial: One form of mobile code is active content in a file that\r\n is transferred across a network.\r\n 1b. (O) /U.S. DoD/ \"Software modules obtained from remote systems,\r\n transferred across a network, and then downloaded and executed on\r\n local systems without explicit installation or execution by the\r\n recipient.\" [JP1]\r\n 2a. (O) /U.S. DoD/ Technology that enables the creation of\r\n executable information that can be delivered to an information\r\n system and directly executed on any hardware/software architecture\r\n that has an appropriate host execution environment.\r\n 2b. (O) \"Programs (e.g., script, macro, or other portable\r\n instruction) that can be shipped unchanged to a heterogeneous\r\n collection of platforms and executed with identical semantics\"\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 230 of 436\n\n[SP28]. (See: active content.)\r\nShirey Informational [Page 193]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Mobile code might be malicious. Using techniques such as\r\n \"code signing\" and a \"sandbox\" can reduce the risks of receiving\r\n and executing mobile code.\r\n $ mode\r\n $ mode of operation\r\n 1. (I) /cryptographic operation/ A technique for enhancing the\r\n effect of a cryptographic algorithm or adapting the algorithm for\r\n an application, such as applying a block cipher to a sequence of\r\n data blocks or a data stream. (See: CBC, CCM, CMAC, CFB, CTR, ECB,\r\n OFB.)\r\n 2. (I) /system operation/ A type of security policy that states\r\n the range of classification levels of information that a system is\r\n permitted to handle and the range of clearances and authorizations\r\n of users who are permitted to access the system. (See:\r\n compartmented security mode, controlled security mode, dedicated\r\n security mode, multilevel security mode, partitioned security\r\n mode, system-high security mode. Compare: protection level.)\r\n 3. (I) /IKE/ IKE refers to its various types of ISAKMP-scripted\r\n exchanges of messages as \"modes\". Among these are the following:\r\n - \"Main mode\": One of IKE's two phase 1 modes. (See: ISAKMP.)\r\n - \"Quick mode\": IKE's only phase 2 mode. (See: ISAKMP.)\r\n $ model\r\n See: formal model, security model.\r\n $ modulus\r\n (I) The defining constant in modular arithmetic, and usually a\r\n part of the public key in asymmetric cryptography that is based on\r\n modular arithmetic. (See: Diffie-Hellman-Merkle, RSA.)\r\n $ Mondex\r\n (O) A smartcard-based electronic money system that incorporates\r\n cryptography and can be used to make payments via the Internet.\r\n (See: IOTP.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 231 of 436\n\n$ Morris Worm\r\n (I) A worm program that flooded the ARPANET in November 1988,\r\n causing problems for thousands of hosts. [R1135] (See: community\r\n risk, worm)\r\n $ MOSS\r\n (I) See: MIME Object Security Services.\r\nShirey Informational [Page 194]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ MQV\r\n (N) A key-agreement protocol [Mene] that was proposed by A.J.\r\n Menezes, M. Qu, and S.A. Vanstone in 1995 and is based on the\r\n Diffie-Hellman-Merkle algorithm.\r\n $ MSP\r\n (N) See: Message Security Protocol.\r\n $ multicast security\r\n See: secure multicast\r\n $ Multics\r\n (N) MULTiplexed Information and Computing Service, an MLS computer\r\n timesharing system designed and implemented during 1965-69 by a\r\n consortium including Massachusetts Institute of Technology,\r\n General Electric, and Bell Laboratories, and later offered\r\n commercially by Honeywell.\r\n Tutorial: Multics was one of the first large, general-purpose,\r\n operating systems to include security as a primary goal from the\r\n inception of the design and development and was rated in TCSEC\r\n Class B2. Its many innovative hardware and software security\r\n mechanisms (e.g., protection ring) were adopted by later systems.\r\n $ multilevel secure (MLS)\r\n (I) Describes an information system that is trusted to contain,\r\n and maintain separation between, resources (particularly stored\r\n data) of different security levels. (Examples: BLACKER, CANEWARE,\r\n KSOS, Multics, SCOMP.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 232 of 436\n\nUsage: Usually understood to mean that the system permits\r\n concurrent access by users who differ in their access\r\n authorizations, while denying users access to resources for which\r\n they lack authorization.\r\n $ multilevel security mode\r\n 1. (N) A mode of system operation wherein (a) two or more security\r\n levels of information are allowed to be to be handled concurrently\r\n within the same system when some users having access to the system\r\n have neither a security clearance nor need-to-know for some of the\r\n data handled by the system and (b) separation of the users and the\r\n classified material on the basis, respectively, of clearance and\r\n classification level are dependent on operating system control.\r\n (See: /system operation/ under \"mode\", need to know, protection\r\n level, security clearance. Compare: controlled mode.)\r\nShirey Informational [Page 195]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: Usually abbreviated as \"multilevel mode\". This term was\r\n defined in U.S. Government policy regarding system accreditation,\r\n but the term is also used outside the Government.\r\n 2. (O) A mode of system operation in which all three of the\r\n following statements are true: (a) Some authorized users do not\r\n have a security clearance for all the information handled in the\r\n system. (b) All authorized users have the proper security\r\n clearance and appropriate specific access approval for the\r\n information to which they have access. (c) All authorized users\r\n have a need-to-know only for information to which they have\r\n access. [C4009] (See: formal access approval, protection level.)\r\n $ Multipurpose Internet Mail Extensions (MIME)\r\n (I) An Internet protocol (RFC 2045) that enhances the basic format\r\n of Internet electronic mail messages (RFC 822) (a) to enable\r\n character sets other than U.S. ASCII to be used for textual\r\n headers and content and (b) to carry non-textual and multi-part\r\n content. (See: S/MIME.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 233 of 436\n\n$ mutual suspicion\r\n (I) The state that exists between two interacting system entities\r\n in which neither entity can trust the other to function correctly\r\n with regard to some security requirement.\r\n $ name\r\n (I) Synonym for \"identifier\".\r\n $ naming authority\r\n (O) /U.S. DoD/ An organizational entity responsible for assigning\r\n DNs and for assuring that each DN is meaningful and unique within\r\n its domain. [DoD9]\r\n $ National Computer Security Center (NCSC)\r\n (O) A U.S. DoD organization, housed in NSA, that has\r\n responsibility for encouraging widespread availability of trusted\r\n systems throughout the U.S. Federal Government. It has established\r\n criteria for, and performed evaluations of, computer and network\r\n systems that have a TCB. (See: Rainbow Series, TCSEC.)\r\n $ National Information Assurance Partnership (NIAP)\r\n (N) A joint initiative of NIST and NSA to enhance the quality of\r\n commercial products for information security and increase consumer\r\n confidence in those products through objective evaluation and\r\n testing methods.\r\nShirey Informational [Page 196]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: NIAP is registered, through the U.S. DoD, as a National\r\n Performance Review Reinvention Laboratory. NIAP functions include\r\n the following:\r\n - Developing tests, test methods, and other tools that developers\r\n and testing laboratories may use to improve and evaluate\r\n security products.\r\n - Collaborating with industry and others on research and testing\r\n programs.\r\n - Using the Common Criteria to develop protection profiles and\r\n associated test sets for security products and systems.\r\n - Cooperating with the NIST National Voluntary Laboratory\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 234 of 436\n\nAccreditation Program to develop a program to accredit private-\r\n sector laboratories for the testing of information security\r\n products using the Common Criteria.\r\n - Working to establish a formal, international mutual recognition\r\n scheme for a Common Criteria-based evaluation.\r\n $ National Institute of Standards and Technology (NIST)\r\n (N) A U.S. Department of Commerce organization that promotes U.S.\r\n economic growth by working with industry to develop and apply\r\n technology, measurements, and standards. Has primary U.S.\r\n Government responsibility for INFOSEC standards for sensitive\r\n unclassified information. (See: ANSI, DES, DSA, DSS, FIPS, NIAP,\r\n NSA.)\r\n $ National Reliability and Interoperability Council (NRIC)\r\n (N) An advisory committee chartered by the U.S. Federal\r\n Communications Commission (FCC), with participation by network\r\n service providers and vendors, to provide recommendations to the\r\n FCC for assuring reliability, interoperability, robustness, and\r\n security of wireless, wireline, satellite, cable, and public data\r\n communication networks.\r\n $ national security\r\n (O) /U.S. Government/ The national defense or foreign relations of\r\n the United States of America.\r\n $ National Security Agency (NSA)\r\n (N) A U.S. DoD organization that has primary U.S. Government\r\n responsibility for INFOSEC standards for classified information\r\n and for sensitive unclassified information handled by national\r\n security systems. (See: FORTEZZA, KEA, MISSI, national security\r\n system, NIAP, NIST, SKIPJACK.)\r\n $ national security information\r\n (O) /U.S. Government/ Information that has been determined,\r\n pursuant to Executive Order 12958 or any predecessor order, to\r\n require protection against unauthorized disclosure. [C4009]\r\nShirey Informational [Page 197]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ national security system\r\n (O) /U.S. Government/ Any Government-operated information system\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 235 of 436\n\nfor which the function, operation, or use (a) involves\r\n intelligence activities; (b) involves cryptologic activities\r\n related to national security; (c) involves command and control of\r\n military forces; (d) involves equipment that is an integral part\r\n of a weapon or weapon system; or (e) is critical to the direct\r\n fulfillment of military or intelligence missions and does not\r\n include a system that is to be used for routine administrative and\r\n business applications (including payroll, finance, logistics, and\r\n personnel management applications). [Title 40 U.S.C. Section 1552,\r\n Information Technology Management Reform Act of 1996.] (See: type\r\n 2 product.)\r\n $ natural disaster\r\n (I) /threat action/ See: secondary definitions under \"corruption\"\r\n and \"incapacitation\".\r\n $ NCSC\r\n (O) See: National Computer Security Center.\r\n $ need to know, need-to-know\r\n (I) The necessity for access to, knowledge of, or possession of\r\n specific information required to carry out official duties.\r\n Usage: The compound \"need-to-know\" is commonly used as either an\r\n adjective or a noun.\r\n Tutorial: The need-to-know criterion is used in security\r\n procedures that require a custodian of sensitive information,\r\n prior to disclosing the information to someone else, to establish\r\n that the intended recipient has proper authorization to access the\r\n information.\r\n $ network\r\n (I) An information system comprised of a collection of\r\n interconnected nodes. (See: computer network.)\r\n $ Network Hardware Layer\r\n (I) See: Internet Protocol Suite.\r\n $ Network Interface Layer\r\n (I) See: Internet Protocol Suite.\r\n $ Network Layer Security Protocol (NLSP).\r\n (N) An OSI protocol (IS0 11577) for end-to-end encryption services\r\n at the top of OSIRM Layer 3. NLSP is derived from SP3 but is more\r\n complex. (Compare: IPsec.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 236 of 436\n\nShirey Informational [Page 198]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Network Substrate Layer\r\n (I) Synonym for \"Network Hardware Layer\".\r\n $ network weaving\r\n (I) A penetration technique in which an intruder avoids detection\r\n and traceback by using multiple, linked, communication networks to\r\n access and attack a system. [C4009]\r\n $ NIAP\r\n (N) See: National Information Assurance Partnership.\r\n $ nibble\r\n (D) Half of a byte (i.e., usually, 4 bits).\r\n Deprecated Term: To avoid international misunderstanding, IDOCs\r\n SHOULD NOT use this term; instead, state the size of the block\r\n explicitly (e.g., \"4-bit block\"). (See: Deprecated Usage under\r\n \"Green Book\".)\r\n $ NIPRNET\r\n (O) The U.S. DoD's common-use Non-Classified Internet Protocol\r\n Router Network; the part of the Internet that is wholly controlled\r\n by the U.S. DoD and is used for official DoD business.\r\n $ NIST\r\n (N) See: National Institute of Standards and Technology.\r\n $ NLSP\r\n (N) See: Network Layer Security Protocol\r\n $ no-lone zone\r\n (I) A room or other space or area to which no person may have\r\n unaccompanied access and that, when occupied, is required to be\r\n occupied by two or more appropriately authorized persons. [C4009]\r\n (See: dual control.)\r\n $ no-PIN ORA (NORA)\r\n (O) /MISSI/ An organizational RA that operates in a mode in which\r\n the ORA performs no card management functions and, therefore, does\r\n not require knowledge of either the SSO PIN or user PIN for an end\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 237 of 436\n\nuser's FORTEZZA PC card.\r\n $ node\r\n (I) A collection of related subsystems located on one or more\r\n computer platforms at a single site. (See: site.)\r\nShirey Informational [Page 199]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ nonce\r\n (I) A random or non-repeating value that is included in data\r\n exchanged by a protocol, usually for the purpose of guaranteeing\r\n liveness and thus detecting and protecting against replay attacks.\r\n (See: fresh.)\r\n $ non-critical\r\n See: critical.\r\n $ non-repudiation service\r\n 1. (I) A security service that provide protection against false\r\n denial of involvement in an association (especially a\r\n communication association that transfers data). (See: repudiation,\r\n time stamp.)\r\n Tutorial: Two separate types of denial are possible -- an entity\r\n can deny that it sent a data object, or it can deny that it\r\n received a data object -- and, therefore, two separate types of\r\n non-repudiation service are possible. (See: non-repudiation with\r\n proof of origin, non-repudiation with proof of receipt.)\r\n 2. (D) \"Assurance [that] the sender of data is provided with proof\r\n of delivery and the recipient is provided with proof of the\r\n sender's identity, so neither can later deny having processed the\r\n data.\" [C4009]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 2 because\r\n it bundles two security services -- non-repudiation with proof of\r\n origin, and non-repudiation with proof of receipt -- that can be\r\n provided independently of each other.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 238 of 436\n\nUsage: IDOCs SHOULD distinguish between the technical aspects and\r\n the legal aspects of a non-repudiation service:\r\n - \"Technical non-repudiation\": Refers to the assurance a relying\r\n party has that if a public key is used to validate a digital\r\n signature, then that signature had to have been made by the\r\n corresponding private signature key. [SP32]\r\n - \"Legal non-repudiation\": Refers to how well possession or\r\n control of the private signature key can be established. [SP32]\r\n Tutorial: Non-repudiation service does not prevent an entity from\r\n repudiating a communication. Instead, the service provides\r\n evidence that can be stored and later presented to a third party\r\n to resolve disputes that arise if and when a communication is\r\n repudiated by one of the entities involved.\r\nShirey Informational [Page 200]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Ford describes the six phases of a complete non-repudiation\r\n service and uses \"critical action\" to refer to the act of\r\n communication that is the subject of the service [For94, For97]:\r\n -------- -------- -------- -------- -------- . --------\r\n Phase 1: Phase 2: Phase 3: Phase 4: Phase 5: . Phase 6:\r\n Request Generate Transfer Verify Retain . Resolve\r\n Service Evidence Evidence Evidence Evidence . Dispute\r\n -------- -------- -------- -------- -------- . --------\r\n Service Critical Evidence Evidence Archive . Evidence\r\n Request =\u003e Action =\u003e Stored =\u003e Is =\u003e Evidence . Is\r\n Is Made Occurs For Later Tested In Case . Verified\r\n and Use | ^ Critical . ^\r\n Evidence v | Action Is . |\r\n Is +-------------------+ Repudiated . |\r\n Generated |Verifiable Evidence|------\u003e ... . ----+\r\n +-------------------+\r\n Phase / Explanation\r\n -------------------\r\n 1. Request service: Before the critical action, the service\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 239 of 436\n\nrequester asks, either implicitly or explicitly, to have\r\n evidence of the action be generated.\r\n 2. Generate evidence: When the critical action occurs, evidence is\r\n generated by a process involving the potential repudiator and\r\n possibly also a trusted third party.\r\n 3. Transfer evidence: The evidence is transferred to the requester\r\n or stored by a third party, for later use (if needed).\r\n 4. Verify evidence: The entity that holds the evidence tests it to\r\n be sure that it will suffice if a dispute arises.\r\n 5. Retain evidence: The evidence is retained for possible future\r\n retrieval and use.\r\n 6. Resolve dispute: In this phase, which occurs only if the\r\n critical action is repudiated, the evidence is retrieved from\r\n storage, presented, and verified to resolve the dispute.\r\n $ non-repudiation with proof of origin\r\n (I) A security service that provides the recipient of data with\r\n evidence that proves the origin of the data, and thus protects the\r\n recipient against an attempt by the originator to falsely deny\r\n sending the data. (See: non-repudiation service.)\r\n Tutorial: This service is a strong version of data origin\r\n authentication service. This service can not only verify the\r\n identity of a system entity that is the original source of\r\n received data; it can also provide proof of that identity to a\r\n third party.\r\nShirey Informational [Page 201]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ non-repudiation with proof of receipt\r\n (I) A security service that provides the originator of data with\r\n evidence that proves the data was received as addressed, and thus\r\n protects the originator against an attempt by the recipient to\r\n falsely deny receiving the data. (See: non-repudiation service.)\r\n $ non-volatile media\r\n (I) Storage media that, once written into, provide stable storage\r\n of information without an external power supply. (Compare:\r\n permanent storage, volatile media.)\r\n $ NORA\r\n (O) See: no-PIN ORA.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 240 of 436\n\n$ notarization\r\n (I) Registration of data under the authority or in the care of a\r\n trusted third party, thus making it possible to provide subsequent\r\n assurance of the accuracy of characteristics claimed for the data,\r\n such as content, origin, time of existence, and delivery.\r\n [I7498-2] (See: digital notary.)\r\n $ NRIC\r\n (N) See: Network Reliability and Interoperability Council.\r\n $ NSA\r\n (N) See: National Security Agency\r\n $ null\r\n (N) /encryption/ \"Dummy letter, letter symbol, or code group\r\n inserted into an encrypted message to delay or prevent its\r\n decryption or to complete encrypted groups for transmission or\r\n transmission security purposes.\" [C4009]\r\n $ NULL encryption algorithm\r\n (I) An algorithm [R2410] that is specified as doing nothing to\r\n transform plaintext data; i.e., a no-op. It originated because ESP\r\n always specifies the use of an encryption algorithm for\r\n confidentiality. The NULL encryption algorithm is a convenient way\r\n to represent the option of not applying encryption in ESP (or in\r\n any other context where a no-op is needed). (Compare: null.)\r\n $ OAKLEY\r\n (I) A key establishment protocol (proposed for IPsec but\r\n superseded by IKE) based on the Diffie-Hellman-Merkle algorithm\r\n and designed to be a compatible component of ISAKMP. [R2412]\r\n Tutorial: OAKLEY establishes a shared key with an assigned\r\n identifier and associated authenticated identities for parties;\r\nShirey Informational [Page 202]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n i.e., OAKLEY provides authentication service to ensure the\r\n entities of each other's identity, even if the Diffie-Hellman-\r\n Merkle exchange is threatened by active wiretapping. Also, it\r\n provides public-key forward secrecy for the shared key and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 241 of 436\n\nsupports key updates, incorporation of keys distributed by out-of-\r\n band mechanisms, and user-defined abstract group structures for\r\n use with Diffie-Hellman-Merkle.\r\n $ object\r\n (I) /formal model/ Trusted-system modeling usage: A system\r\n component that contains or receives information. (See: Bell-\r\n LaPadula model, object reuse, trusted system.)\r\n $ object identifier (OID)\r\n 1. (N) An official, globally unique name for a thing, written as a\r\n sequence of integers (which are formed and assigned as defined in\r\n the ASN.1 standard) and used to reference the thing in abstract\r\n specifications and during negotiation of security services in a\r\n protocol.\r\n 2. (O) \"A value (distinguishable from all other such values)\r\n [that] is associated with an object.\" [X680]\r\n Tutorial: Objects named by OIDs are leaves of the object\r\n identifier tree (which is similar to but different from the X.500\r\n Directory Information Tree). Each arc (i.e., each branch of the\r\n tree) is labeled with a non-negative integer. An OID is the\r\n sequence of integers on the path leading from the root of the tree\r\n to a named object.\r\n The OID tree has three arcs immediately below the root: {0} for\r\n use by ITU-T, {1} for use by ISO, and {2} for use by both jointly.\r\n Below ITU-T are four arcs, where {0 0} is for ITU-T\r\n recommendations. Below {0 0} are 26 arcs, one for each series of\r\n recommendations starting with the letters A to Z, and below these\r\n are arcs for each recommendation. Thus, the OID for ITU-T\r\n Recommendation X.509 is {0 0 24 509}. Below ISO are four arcs,\r\n where {1 0 }is for ISO standards, and below these are arcs for\r\n each ISO standard. Thus, the OID for ISO/IEC 9594-8 (the ISO\r\n number for X.509) is {1 0 9594 8}.\r\n ANSI registers organization names below the branch {joint-iso-\r\n ccitt(2) country(16) US(840) organization(1) gov(101) csor(3)}.\r\n The NIST CSOR records PKI objects below the branch {joint-iso-itu-\r\n t(2) country(16) us(840) organization (1) gov(101) csor(3)}. The\r\n U.S. DoD registers INFOSEC objects below the branch {joint-iso-\r\n itu-t(2) country(16) us(840) organization(1) gov(101) dod(2)\r\n infosec(1)}.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 242 of 436\n\nShirey Informational [Page 203]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n The IETF's Public-Key Infrastructure (pkix) Working Group\r\n registers PKI objects below the branch {iso(1) identified-\r\n organization(3) dod(6) internet(1) security(5) mechanisms(5)\r\n pkix(7)}. [R3280]\r\n $ object reuse\r\n (N) /COMPUSEC/ Reassignment and reuse of an area of a storage\r\n medium (e.g., random-access memory, floppy disk, magnetic tape)\r\n that once contained sensitive data objects. Before being\r\n reassigned for use by a new subject, the area needs to be erased\r\n or, in some cases, purged. [NCS04] (See: object.)\r\n $ obstruction\r\n (I) A type of threat action that interrupts delivery of system\r\n services by hindering system operations. (See: disruption.)\r\n Tutorial: This type of threat action includes the following\r\n subtypes:\r\n - \"Interference\": Disruption of system operations by blocking\r\n communication of user data or control information. (See:\r\n jamming.)\r\n - \"Overload\": Hindrance of system operation by placing excess\r\n burden on the performance capabilities of a system component.\r\n (See: flooding.)\r\n $ OCSP\r\n (I) See: Online Certificate Status Protocol.\r\n $ octet\r\n (I) A data unit of eight bits. (Compare: byte.)\r\n Usage: This term is used in networking (especially in OSI\r\n standards) in preference to \"byte\", because some systems use\r\n \"byte\" for data storage units of a size other than eight bits.\r\n $ OFB\r\n (N) See: output feedback.\r\n $ off-line attack\r\n (I) See: secondary definition under \"attack\".\r\n $ ohnosecond\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 243 of 436\n\n(D) That minuscule fraction of time in which you realize that your\r\n private key has been compromised.\r\n Deprecated Usage: IDOCs SHOULD NOT use this term; it is a joke for\r\n English speakers. (See: Deprecated Usage under \"Green Book\".)\r\nShirey Informational [Page 204]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ OID\r\n (N) See: object identifier.\r\n $ Online Certificate Status Protocol (OCSP)\r\n (I) An Internet protocol [R2560] used by a client to obtain from a\r\n server the validity status and other information about a digital\r\n certificate. (Mentioned in [X509] but not specified there.)\r\n Tutorial: In some applications, such as those involving high-value\r\n commercial transactions, it may be necessary either (a) to obtain\r\n certificate revocation status that is timelier than is possible\r\n with CRLs or (b) to obtain other kinds of status information. OCSP\r\n may be used to determine the current revocation status of a\r\n digital certificate, in lieu of or as a supplement to checking\r\n against a periodic CRL. An OCSP client issues a status request to\r\n an OCSP server and suspends acceptance of the certificate in\r\n question until the server provides a response.\r\n $ one-time pad\r\n 1. (N) A manual encryption system in the form of a paper pad for\r\n one-time use.\r\n 2. (I) An encryption algorithm in which the key is a random\r\n sequence of symbols and each symbol is used for encryption only\r\n one time -- i.e., used to encrypt only one plaintext symbol and\r\n thus produce only one ciphertext symbol -- and a copy of the key\r\n is used similarly for decryption.\r\n Tutorial: To ensure one-time use, the copy of the key used for\r\n encryption is destroyed after use, as is the copy used for\r\n decryption. This is the only encryption algorithm that is truly\r\n unbreakable, even given unlimited resources for cryptanalysis\r\n [Schn], but key management costs and synchronization problems make\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 244 of 436\n\nit impractical except in special situations.\r\n $ one-time password, One-Time Password (OTP)\r\n 1. (I) /not capitalized/ A \"one-time password\" is a simple\r\n authentication technique in which each password is used only once\r\n as authentication information that verifies an identity. This\r\n technique counters the threat of a replay attack that uses\r\n passwords captured by wiretapping.\r\n 2. (I) /capitalized/ \"One-Time Password\" is an Internet protocol\r\n [R2289] that is based on S/KEY and uses a cryptographic hash\r\n function to generate one-time passwords for use as authentication\r\n information in system login and in other processes that need\r\n protection against replay attacks.\r\nShirey Informational [Page 205]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ one-way encryption\r\n (I) Irreversible transformation of plain text to cipher text, such\r\n that the plain text cannot be recovered from the cipher text by\r\n other than exhaustive procedures even if the cryptographic key is\r\n known. (See: brute force, encryption.)\r\n $ one-way function\r\n (I) \"A (mathematical) function, f, [that] is easy to compute, but\r\n which for a general value y in the range, it is computationally\r\n difficult to find a value x in the domain such that f(x) = y.\r\n There may be a few values of y for which finding x is not\r\n computationally difficult.\" [X509]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n \"cryptographic hash\".\r\n $ onion routing\r\n (I) A system that can be used to provide both (a) data\r\n confidentiality and (b) traffic-flow confidentiality for network\r\n packets, and also provide (c) anonymity for the source of the\r\n packets.\r\n Tutorial: The source, instead of sending a packet directly to the\r\n intended destination, sends it to an \"onion routing proxy\" that\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 245 of 436\n\nbuilds an anonymous connection through several other \"onion\r\n routers\" to the destination. The proxy defines a route through the\r\n \"onion routing network\" by encapsulating the original payload in a\r\n layered data packet called an \"onion\", in which each layer defines\r\n the next hop in the route and each layer is also encrypted. Along\r\n the route, each onion router that receives the onion peels off one\r\n layer; decrypts that layer and reads from it the address of the\r\n next onion router on the route; pads the remaining onion to some\r\n constant size; and sends the padded onion to that next router.\r\n $ open security environment\r\n (O) /U.S. DoD/ A system environment that meets at least one of the\r\n following two conditions: (a) Application developers (including\r\n maintainers) do not have sufficient clearance or authorization to\r\n provide an acceptable presumption that they have not introduced\r\n malicious logic. (b) Configuration control does not provide\r\n sufficient assurance that applications and the equipment are\r\n protected against the introduction of malicious logic prior to and\r\n during the operation of system applications. [NCS04] (See: \"first\r\n law\" under \"Courtney's laws\". Compare: closed security\r\n environment.)\r\nShirey Informational [Page 206]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ open storage\r\n (N) /U.S. Government/ \"Storage of classified information within an\r\n accredited facility, but not in General Services Administration\r\n approved secure containers, while the facility is unoccupied by\r\n authorized personnel.\" [C4009]\r\n $ Open Systems Interconnection (OSI) Reference Model (OSIRM)\r\n (N) A joint ISO/ITU-T standard [I7498-1] for a seven-layer,\r\n architectural communication framework for interconnection of\r\n computers in networks. (See: OSIRM Security Architecture. Compare:\r\n Internet Protocol Suite.)\r\n Tutorial: OSIRM-based standards include communication protocols\r\n that are mostly incompatible with the IPS, but also include\r\n security models, such as X.509, that are used in the Internet.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 246 of 436\n\nThe OSIRM layers, from highest to lowest, are (7) Application, (6)\r\n Presentation, (5) Session, (4) Transport, (3) Network, (2) Data\r\n Link, and (1) Physical.\r\n Usage: This Glossary refers to OSIRM layers by number to avoid\r\n confusing them with IPS layers, which are referred to by name.\r\n Some unknown person described how the OSIRM layers correspond to\r\n the seven deadly sins:\r\n 7. Wrath: Application is always angry with the mess it sees below\r\n itself. (Hey! Who is it to be pointing fingers?)\r\n 6. Sloth: Presentation is too lazy to do anything productive by\r\n itself.\r\n 5. Lust: Session is always craving and demanding what truly\r\n belongs to Application's functionality.\r\n 4. Avarice: Transport wants all of the end-to-end functionality.\r\n (Of course, it deserves it, but life isn't fair.)\r\n 3. Gluttony: (Connection-Oriented) Network is overweight and\r\n overbearing after trying too often to eat Transport's lunch.\r\n 2. Envy: Poor Data Link is always starved for attention. (With\r\n Asynchronous Transfer Mode, maybe now it is feeling less\r\n neglected.)\r\n 1. Pride: Physical has managed to avoid much of the controversy,\r\n and nearly all of the embarrassment, suffered by the others.\r\n John G. Fletcher described how the OSIRM layers correspond to Snow\r\n White's dwarf friends:\r\n 7. Doc: Application acts as if it is in charge, but sometimes\r\n muddles its syntax.\r\nShirey Informational [Page 207]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 6. Sleepy: Presentation is indolent, being guilty of the sin of\r\n Sloth.\r\n 5. Dopey: Session is confused because its charter is not very\r\n clear.\r\n 4. Grumpy: Transport is irritated because Network has encroached\r\n on Transport's turf.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 247 of 436\n\n3. Happy: Network smiles for the same reason that Transport is\r\n irritated.\r\n 2. Sneezy: Data Link makes loud noises in the hope of attracting\r\n attention.\r\n 1. Bashful: Physical quietly does its work, unnoticed by the\r\n others.\r\n $ operational integrity\r\n (I) Synonym for \"system integrity\"; this synonym emphasizes the\r\n actual performance of system functions rather than just the\r\n ability to perform them.\r\n $ operational security\r\n 1. (I) System capabilities, or performance of system functions,\r\n that are needed either (a) to securely manage a system or (b) to\r\n manage security features of a system. (Compare: operations\r\n security (OPSEC).)\r\n Usage: IDOCs that use this term SHOULD state a definition because\r\n (a) the definition provided here is general and vague and (b) the\r\n term could easily be confused with \"operations security\", which is\r\n a different concept.\r\n Tutorial: For example, in the context of an Internet service\r\n provider, the term could refer to capabilities to manage network\r\n devices in the event of attacks, simplify troubleshooting, keep\r\n track of events that affect system integrity, help analyze sources\r\n of attacks, and provide administrators with control over network\r\n addresses and protocols to help mitigate the most common attacks\r\n and exploits. [R3871]\r\n 2. (D) Synonym for \"administrative security\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"administrative security\". Any type of security may affect\r\n system operations; therefore, the term may be misleading. Instead,\r\n use \"administrative security\", \"communication security\", \"computer\r\n security\", \"emanations security\", \"personnel security\", \"physical\r\n security\", or whatever specific type is meant. (See: security\r\n architecture. Compare: operational integrity, OPSEC.)\r\nShirey Informational [Page 208]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 248 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ operations security (OPSEC)\r\n (I) A process to identify, control, and protect evidence of the\r\n planning and execution of sensitive activities and operations, and\r\n thereby prevent potential adversaries from gaining knowledge of\r\n capabilities and intentions. (See: communications cover. Compare:\r\n operational security.)\r\n $ operator\r\n (I) A person who has been authorized to direct selected functions\r\n of a system. (Compare: manager, user.)\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because a system operator may or may not be treated as a \"user\".\r\n $ OPSEC\r\n 1. (I) Abbreviation for \"operations security\".\r\n 2. (D) Abbreviation for \"operational security\".\r\n Deprecated Usage: IDOCs SHOULD NOT use this abbreviation for\r\n \"operational security\" (as defined in this Glossary), because its\r\n use for \"operations security\" has been well established for many\r\n years, particular in the military community.\r\n $ ORA\r\n See: organizational registration authority.\r\n $ Orange Book\r\n (D) /slang/ Synonym for \"Trusted Computer System Evaluation\r\n Criteria\" [CSC1, DoD1].\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n \"Trusted Computer System Evaluation Criteria\" [CSC1, DoD1].\r\n Instead, use the full, proper name of the document or, in\r\n subsequent references, the abbreviation \"TCSEC\". (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ organizational certificate\r\n 1. (I) An X.509 public-key certificate in which the \"subject\"\r\n field contains the name of an institution or set (e.g., a\r\n business, government, school, labor union, club, ethnic group,\r\n nationality, system, or group of individuals playing the same\r\n role), rather than the name of an individual person or device.\r\n (Compare: persona certificate, role certificate.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 249 of 436\n\nTutorial: Such a certificate might be issued for one of the\r\n following purposes:\r\nShirey Informational [Page 209]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - To enable an individual to prove membership in the\r\n organization.\r\n - To enable an individual to represent the organization, i.e., to\r\n act in its name and with its powers or permissions.\r\n 2. (O) /MISSI/ A type of MISSI X.509 public-key certificate that\r\n is issued to support organizational message handling for the U.S.\r\n DoD's Defense Message System.\r\n $ organizational registration authority (ORA)\r\n 1. (I) /PKI/ An RA for an organization.\r\n 2. (O) /MISSI/ An end entity that (a) assists a PCA, CA, or SCA to\r\n register other end entities, by gathering, verifying, and entering\r\n data and forwarding it to the signing authority and (b) may also\r\n assist with card management functions. An ORA is a local\r\n administrative authority, and the term refers both to the role and\r\n to the person who plays that role. An ORA does not sign\r\n certificates, CRLs, or CKLs. (See: no-PIN ORA, SSO-PIN ORA, user-\r\n PIN ORA.)\r\n $ origin authentication\r\n (D) Synonym for \"data origin authentication\". (See:\r\n authentication, data origin authentication.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it suggests\r\n careless use of the internationally standardized term \"data origin\r\n authentication\" and also could be confused with \"peer entity\r\n authentication.\"\r\n $ origin authenticity\r\n (D) Synonym for \"data origin authentication\". (See: authenticity,\r\n data origin authentication.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it suggests\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 250 of 436\n\ncareless use of the internationally standardized term \"data origin\r\n authentication\" and mixes concepts in a potentially misleading\r\n way.\r\n $ OSI, OSIRM\r\n (N) See: Open Systems Interconnection Reference Model.\r\n $ OSIRM Security Architecture\r\n (N) The part of the OSIRM [I7498-2] that specifies the security\r\n services and security mechanisms that can be applied to protect\r\n communications between two systems. (See: security architecture.)\r\nShirey Informational [Page 210]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: This part of the OSIRM includes an allocation of\r\n security services to protocol layers. The following table shows\r\n which security services (see definitions in this Glossary) are\r\n permitted by the OSIRM in each of its layers. (Also, an\r\n application process that operates above the Application Layer may\r\n itself provide security services.) Similarly, the table suggests\r\n which services are suitable for each IPS layer. However,\r\n explaining and justifying these allocations is beyond the scope of\r\n this Glossary.\r\n Legend for Table Entries:\r\n O = Yes, [I7498-2] permits the service in this OSIRM layer.\r\n I = Yes, the service can be incorporated in this IPS layer.\r\n * = This layer subsumed by Application Layer in IPS.\r\n IPS Protocol Layers +-----------------------------------------+\r\n |Network| Net |In-| Trans | Application |\r\n | H/W |Inter|ter| -port | |\r\n | |-face|net| | |\r\n OSIRM Protocol Layers +-----------------------------------------+\r\n | 1 | 2 | 3 | 4 | 5 | 6 | 7 |\r\n Confidentiality +-----------------------------------------+\r\n - Datagram | O I | O I | O I | O I | | O * | O I |\r\n - Selective Field | | | I | | | O * | O I |\r\n - Traffic Flow | O | | O | | | | O |\r\n -- Full | I | | | | | | |\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 251 of 436\n\n-- Partial | | I | I | | | | I |\r\n Integrity +-----------------------------------------+\r\n - Datagram | I | I | O I | O I | | | O I |\r\n - Selective Field | | | I | | | | O I |\r\n - Stream | | | O I | O I | | | O I |\r\n Authentication +-----------------------------------------+\r\n - Peer Entity | | I | O I | O I | | | O I |\r\n - Data Origin | | I | O I | O I | | | O I |\r\n Access Control +-----------------------------------------+\r\n - type as appropriate | | I | O I | O I | | | O I |\r\n Non-Repudiation +-----------------------------------------+\r\n - of Origin | | | | | | | O I |\r\n - of Receipt | | | | | | | O I |\r\n +-----------------------------------------+\r\n $ OTAR\r\n (N) See: over-the-air rekeying.\r\n $ OTP\r\n (I) See: One-Time Password.\r\nShirey Informational [Page 211]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ out-of-band\r\n (I) /adjective, adverb/ Information transfer using a channel or\r\n method that is outside (i.e., separate from or different from) the\r\n main channel or normal method.\r\n Tutorial: Out-of-band mechanisms are often used to distribute\r\n shared secrets (e.g., a symmetric key) or other sensitive\r\n information items (e.g., a root key) that are needed to initialize\r\n or otherwise enable the operation of cryptography or other\r\n security mechanisms. Example: Using postal mail to distribute\r\n printed or magnetic media containing symmetric cryptographic keys\r\n for use in Internet encryption devices. (See: key distribution.)\r\n $ output feedback (OFB)\r\n (N) A block cipher mode that modifies ECB mode to operate on\r\n plaintext segments of variable length less than or equal to the\r\n block length. [FP081] (See: block cipher, [SP38A].)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 252 of 436\n\nTutorial: This mode operates by directly using the algorithm's\r\n previously generated output block as the algorithm's next input\r\n block (i.e., by \"feeding back\" the output block) and combining\r\n (exclusive OR-ing) the output block with the next plaintext\r\n segment (of block length or less) to form the next ciphertext\r\n segment.\r\n $ outside attack\r\n (I) See: secondary definition under \"attack\". Compare: outsider.)\r\n $ outsider\r\n (I) A user (usually a person) that accesses a system from a\r\n position that is outside the system's security perimeter.\r\n (Compare: authorized user, insider, unauthorized user.)\r\n Tutorial: The actions performed by an outsider in accessing the\r\n system may be either authorized or unauthorized; i.e., an outsider\r\n may act either as an authorized user or as an unauthorized user.\r\n $ over-the-air rekeying (OTAR)\r\n (N) Changing a key in a remote cryptographic device by sending a\r\n new key directly to the device via a channel that the device is\r\n protecting. [C4009]\r\n $ overload\r\n (I) /threat action/ See: secondary definition under \"obstruction\".\r\n $ P1363\r\n (N) See: IEEE P1363.\r\nShirey Informational [Page 212]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ PAA\r\n (O) See: policy approving authority.\r\n $ package\r\n (N) /Common Criteria/ A reusable set of either functional or\r\n assurance components, combined in a single unit to satisfy a set\r\n of identified security objectives. (Compare: protection profile.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 253 of 436\n\nExample: The seven EALs defined in Part 3 of the Common Criteria\r\n are predefined assurance packages.\r\n Tutorial: A package is a combination of security requirement\r\n components and is intended to be reusable in the construction of\r\n either more complex packages or protection profiles and security\r\n targets. A package expresses a set of either functional or\r\n assurance requirements that meet some particular need, expressed\r\n as a set of security objectives.\r\n $ packet\r\n (I) A block of data that is carried from a source to a destination\r\n through a communication channel or, more generally, across a\r\n network. (Compare: datagram, PDU.)\r\n $ packet filter\r\n (I) See: secondary definition under \"filtering router\".\r\n $ packet monkey\r\n (D) /slang/ Someone who floods a system with packets, creating a\r\n denial-of-service condition for the system's users. (See:\r\n cracker.)\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ pagejacking\r\n (D) /slang/ A contraction of \"Web page hijacking\". A masquerade\r\n attack in which the attacker copies (steals) a home page or other\r\n material from the target server, rehosts the page on a server the\r\n attacker controls, and causes the rehosted page to be indexed by\r\n the major Web search services, thereby diverting browsers from the\r\n target server to the attacker's server.\r\n Deprecated Term: IDOCs SHOULD NOT use this contraction. The term\r\n is not listed in most dictionaries and could confuse international\r\n readers. (See: Deprecated Usage under \"Green Book\".)\r\nShirey Informational [Page 213]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 254 of 436\n\n$ PAN\r\n (O) See: primary account number.\r\n $ PAP\r\n (I) See: Password Authentication Protocol.\r\n $ parity bit\r\n (I) A checksum that is computed on a block of bits by computing\r\n the binary sum of the individual bits in the block and then\r\n discarding all but the low-order bit of the sum. (See: checksum.)\r\n $ partitioned security mode\r\n (N) A mode of system operation wherein all users having access to\r\n the system have the necessary security clearances for all data\r\n handled by the system, but some users might not have either formal\r\n access approval or need-to-know for all the data. (See: /system\r\n operation/ under \"mode\", formal access approval, need to know,\r\n protection level, security clearance.)\r\n Usage: Usually abbreviated as \"partitioned mode\". This term was\r\n defined in U.S. Government policy on system accreditation.\r\n $ PASS\r\n (N) See: personnel authentication system string.\r\n $ passive attack\r\n (I) See: secondary definition under \"attack\".\r\n $ passive user\r\n (I) See: secondary definition under \"system user\".\r\n $ passive wiretapping\r\n (I) A wiretapping attack that attempts only to observe a\r\n communication flow and gain knowledge of the data it contains, but\r\n does not alter or otherwise affect that flow. (See: wiretapping.\r\n Compare: passive attack, active wiretapping.)\r\n $ password\r\n 1a. (I) A secret data value, usually a character string, that is\r\n presented to a system by a user to authenticate the user's\r\n identity. (See: authentication information, challenge-response,\r\n PIN, simple authentication.)\r\n 1b. (O) \"A character string used to authenticate an identity.\"\r\n [CSC2]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 255 of 436\n\nShirey Informational [Page 214]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 1c. (O) \"A string of characters (letters, numbers, and other\r\n symbols) used to authenticate an identity or to verify access\r\n authorization.\" [FP140]\r\n 1d. (O) \"A secret that a claimant memorizes and uses to\r\n authenticate his or her identity. Passwords are typically\r\n character strings.\" [SP63]\r\n Tutorial: A password is usually paired with a user identifier that\r\n is explicit in the authentication process, although in some cases\r\n the identifier may be implicit. A password is usually verified by\r\n matching it to a stored value held by the access control system\r\n for that identifier.\r\n Using a password as authentication information is based on\r\n assuming that the password is known only by the system entity for\r\n which the identity is being authenticated. Therefore, in a network\r\n environment where wiretapping is possible, simple authentication\r\n that relies on transmission of static (i.e., repetitively used)\r\n passwords in cleartext form is inadequate. (See: one-time\r\n password, strong authentication.)\r\n $ Password Authentication Protocol (PAP)\r\n (I) A simple authentication mechanism in PPP. In PAP, a user\r\n identifier and password are transmitted in cleartext form. [R1334]\r\n (See: CHAP.)\r\n $ password sniffing\r\n (D) /slang/ Passive wiretapping to gain knowledge of passwords.\r\n (See: Deprecated Usage under \"sniffing\".)\r\n $ path discovery\r\n (I) For a digital certificate, the process of finding a set of\r\n public-key certificates that comprise a certification path from a\r\n trusted key to that specific certificate.\r\n $ path validation\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 256 of 436\n\n(I) The process of validating (a) all of the digital certificates\r\n in a certification path and (b) the required relationships between\r\n those certificates, thus validating the contents of the last\r\n certificate on the path. (See: certificate validation.)\r\n Tutorial: To promote interoperable PKI applications in the\r\n Internet, RFC 3280 specifies a detailed algorithm for validation\r\n of a certification path.\r\nShirey Informational [Page 215]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ payment card\r\n (N) /SET/ Collectively refers \"to credit cards, debit cards,\r\n charge cards, and bank cards issued by a financial institution and\r\n which reflects a relationship between the cardholder and the\r\n financial institution.\" [SET2]\r\n $ payment gateway\r\n (O) /SET/ A system operated by an acquirer, or a third party\r\n designated by an acquirer, to provide electronic commerce services\r\n to the merchants in support of the acquirer, and which interfaces\r\n to the acquirer to support the authorization, capture, and\r\n processing of merchant payment messages, including payment\r\n instructions from cardholders. [SET1, SET2]\r\n $ payment gateway certification authority (SET PCA)\r\n (O) /SET/ A CA that issues digital certificates to payment\r\n gateways and is operated on behalf of a payment card brand, an\r\n acquirer, or another party according to brand rules. A SET PCA\r\n issues a CRL for compromised payment gateway certificates. [SET2]\r\n (See: PCA.)\r\n $ PC card\r\n (N) A type of credit card-sized, plug-in peripheral device that\r\n was originally developed to provide memory expansion for portable\r\n computers, but is also used for other kinds of functional\r\n expansion. (See: FORTEZZA, PCMCIA.)\r\n Tutorial: The international PC Card Standard defines a non-https://www.ietf.org/rfc/rfc4949.txt\r\nPage 257 of 436\n\nproprietary form factor in three sizes -- Types I, II, and III --\r\n each of which have a 68-pin interface between the card and the\r\n socket into which it plugs. All three types have the same length\r\n and width, roughly the size of a credit card, but differ in their\r\n thickness from 3.3 to 10.5 mm. Examples include storage modules,\r\n modems, device interface adapters, and cryptographic modules.\r\n $ PCA\r\n (D) Abbreviation of various kinds of \"certification authority\".\r\n (See: Internet policy certification authority, (MISSI) policy\r\n creation authority, (SET) payment gateway certification\r\n authority.)\r\n Deprecated Usage: An IDOC that uses this abbreviation SHOULD\r\n define it at the point of first use.\r\n $ PCI\r\n (N) See: \"protocol control information\" under \"protocol data\r\n unit\".\r\nShirey Informational [Page 216]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ PCMCIA\r\n (N) Personal Computer Memory Card International Association, a\r\n group of manufacturers, developers, and vendors, founded in 1989\r\n to standardize plug-in peripheral memory cards for personal\r\n computers and now extended to deal with any technology that works\r\n in the PC Card form factor. (See: PC card.)\r\n $ PDS\r\n (N) See: protective distribution system.\r\n $ PDU\r\n (N) See: protocol data unit.\r\n $ peer entity authentication\r\n (I) \"The corroboration that a peer entity in an association is the\r\n one claimed.\" [I7498-2] (See: authentication.)\r\n $ peer entity authentication service\r\n (I) A security service that verifies an identity claimed by or for\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 258 of 436\n\na system entity in an association. (See: authentication,\r\n authentication service.)\r\n Tutorial: This service is used at the establishment of, or at\r\n times during, an association to confirm the identity of one entity\r\n to another, thus protecting against a masquerade by the first\r\n entity. However, unlike data origin authentication service, this\r\n service requires an association to exist between the two entities,\r\n and the corroboration provided by the service is valid only at the\r\n current time that the service is provided. (See: \"relationship\r\n between data integrity service and authentication services\" under\r\n \"data integrity service\").\r\n $ PEM\r\n (I) See: Privacy Enhanced Mail.\r\n $ penetrate\r\n 1a. (I) Circumvent a system's security protections. (See: attack,\r\n break, violation.)\r\n 1b. (I) Successfully and repeatedly gain unauthorized access to a\r\n protected system resource. [Huff]\r\n $ penetration\r\n (I) /threat action/ See: secondary definition under \"intrusion\".\r\nShirey Informational [Page 217]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ penetration test\r\n (I) A system test, often part of system certification, in which\r\n evaluators attempt to circumvent the security features of a\r\n system. [NCS04, SP42] (See: tiger team.)\r\n Tutorial: Penetration testing evaluates the relative vulnerability\r\n of a system to attacks and identifies methods of gaining access to\r\n a system by using tools and techniques that are available to\r\n adversaries. Testing may be performed under various constraints\r\n and conditions, including a specified level of knowledge of the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 259 of 436\n\nsystem design and implementation. For a TCSEC evaluation, testers\r\n are assumed to have all system design and implementation\r\n documentation, including source code, manuals, and circuit\r\n diagrams, and to work under no greater constraints than those\r\n applied to ordinary users.\r\n $ perfect forward secrecy\r\n (I) For a key agreement protocol, the property that compromises\r\n long-term keying material does not compromise session keys that\r\n were previously derived from the long-term material. (Compare:\r\n public-key forward secrecy.)\r\n Usage: Some existing RFCs use this term but either do not define\r\n it or do not define it precisely. While preparing this Glossary,\r\n we found this to be a muddled area. Experts did not agree. For all\r\n practical purposes, the literature defines \"perfect forward\r\n secrecy\" by stating the Diffie-Hellman-Merkle algorithm. The term\r\n \"public-key forward secrecy\" (suggested by Hilarie Orman) and the\r\n definition stated for it in this Glossary were crafted to be\r\n compatible with current Internet documents, yet be narrow and\r\n leave room for improved terminology.\r\n Challenge to the Internet security community: We need a taxonomy\r\n of terms and definitions to cover the basic properties discussed\r\n here for the full range of cryptographic algorithms and protocols\r\n used in Internet Standards:\r\n Involvement of session keys vs. long-term keys: Experts disagree\r\n about the basic ideas involved:\r\n - One concept of \"forward secrecy\" is that, given observations of\r\n the operation of a key establishment protocol up to time t, and\r\n given some of the session keys derived from those protocol\r\n runs, you cannot derive unknown past session keys or future\r\n session keys.\r\n - A related property is that, given observations of the protocol\r\n and knowledge of the derived session keys, you cannot derive\r\n one or more of the long-term private keys.\r\nShirey Informational [Page 218]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - The \"I\" definition presented above involves a third concept of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 260 of 436\n\n\"forward secrecy\" that refers to the effect of the compromise\r\n of long-term keys.\r\n - All three concepts involve the idea that a compromise of \"this\"\r\n encryption key is not supposed to compromise the \"next\" one.\r\n There also is the idea that compromise of a single key will\r\n compromise only the data protected by the single key. In\r\n Internet literature, the focus has been on protection against\r\n decryption of back traffic in the event of a compromise of\r\n secret key material held by one or both parties to a\r\n communication.\r\n Forward vs. backward: Experts are unhappy with the word \"forward\",\r\n because compromise of \"this\" encryption key also is not supposed\r\n to compromise the \"previous\" one, which is \"backward\" rather than\r\n forward. In S/KEY, if the key used at time t is compromised, then\r\n all keys used prior to that are compromised. If the \"long-term\"\r\n key (i.e., the base of the hashing scheme) is compromised, then\r\n all keys past and future are compromised; thus, you could say that\r\n S/KEY has neither forward nor backward secrecy.\r\n Asymmetric cryptography vs. symmetric: Experts disagree about\r\n forward secrecy in the context of symmetric cryptographic systems.\r\n In the absence of asymmetric cryptography, compromise of any long-\r\n term key seems to compromise any session key derived from the\r\n long-term key. For example, Kerberos isn't forward secret, because\r\n compromising a client's password (thus compromising the key shared\r\n by the client and the authentication server) compromises future\r\n session keys shared by the client and the ticket-granting server.\r\n Ordinary forward secrecy vs. \"perfect\" forward secret: Experts\r\n disagree about the difference between these two. Some say there is\r\n no difference, and some say that the initial naming was\r\n unfortunate and suggest dropping the word \"perfect\". Some suggest\r\n using \"forward secrecy\" for the case where one long-term private\r\n key is compromised, and adding \"perfect\" for when both private\r\n keys (or, when the protocol is multi-party, all private keys) are\r\n compromised.\r\n Acknowledgements: Bill Burr, Burt Kaliski, Steve Kent, Paul Van\r\n Oorschot, Jonathan Trostle, Michael Wiener, and, especially,\r\n Hilarie Orman contributed ideas to this discussion.\r\n $ perimeter\r\n See: security perimeter.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 261 of 436\n\nShirey Informational [Page 219]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ periods processing\r\n (I) A mode of system operation in which information of different\r\n sensitivities is processed at distinctly different times by the\r\n same system, with the system being properly purged or sanitized\r\n between periods. (See: color change.)\r\n Tutorial: The security mode of operation and maximum\r\n classification of data handled by the system is established for an\r\n interval of time and then is changed for the following interval of\r\n time. A period extends from the secure initialization of the\r\n system to the completion of any purging of sensitive data handled\r\n by the system during the period.\r\n $ permanent storage\r\n (I) Non-volatile media that, once written into, can never be\r\n completely erased.\r\n $ permission\r\n 1a. (I) Synonym for \"authorization\". (Compare: privilege.)\r\n 1b. (N) An authorization or set of authorizations to perform\r\n security-relevant functions in the context of role-based access\r\n control. [ANSI]\r\n Tutorial: A permission is a positively stated authorization for\r\n access that (a) can be associated with one or more roles and (b)\r\n enables a user in a role to access a specified set of system\r\n resources by causing a specific set of system actions to be\r\n performed on the resources.\r\n $ persona certificate\r\n (I) An X.509 certificate issued to a system entity that wishes to\r\n use a persona to conceal its true identity when using PEM or other\r\n Internet services that depend on PKI support. (See: anonymity.)\r\n [R1422]\r\n Tutorial: PEM designers intended that (a) a CA issuing persona\r\n certificates would explicitly not be vouching for the identity of\r\n the system entity to whom the certificate is issued, (b) such\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 262 of 436\n\ncertificates would be issued only by CAs subordinate to a policy\r\n CA having a policy stating that purpose (i.e., that would warn\r\n relying parties that the \"subject\" field DN represented only a\r\n persona and not a true, vetted user identity), and (c) the CA\r\n would not need to maintain records binding the true identity of\r\n the subject to the certificate.\r\nShirey Informational [Page 220]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n However, the PEM designers also intended that a CA issuing persona\r\n certificates would establish procedures (d) to enable \"the holder\r\n of a PERSONA certificate to request that his certificate be\r\n revoked\" and (e) to ensure that it did not issue the same subject\r\n DN to multiple users. The latter condition implies that a persona\r\n certificate is not an organizational certificate unless the\r\n organization has just one member or representative.\r\n $ personal identification number (PIN)\r\n 1a. (I) A character string used as a password to gain access to a\r\n system resource. (See: authentication information.)\r\n Example: A cryptographic token typically requires its user to\r\n enter a PIN in order to access information stored in the token and\r\n invoke the token's cryptographic functions.\r\n 1b. (O) An alphanumeric code or password used to authenticate an\r\n identity.\r\n Tutorial: Despite the words \"identification\" and \"number\", a PIN\r\n seldom serves as a user identifier, and a PIN's characters are not\r\n necessarily all numeric. Retail banking applications use 4-digit\r\n numeric user PINs, but the FORTEZZA PC card uses 12-character\r\n alphanumeric SSO PINs. (See: SSO PIN, user PIN.)\r\n A better name for this concept would have been \"personnel\r\n authentication system string\" (PASS), in which case, an\r\n alphanumeric character string for this purpose would have been\r\n called, obviously, a \"PASSword\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 263 of 436\n\n$ personal information\r\n (I) Information about a particular person, especially information\r\n of an intimate or critical nature, that could cause harm or pain\r\n to that person if disclosed to unauthorized parties. Examples:\r\n medical record, arrest record, credit report, academic transcript,\r\n training report, job application, credit card number, Social\r\n Security number. (See: privacy.)\r\n $ personality\r\n 1. (I) Synonym for \"principal\".\r\n 2. (O) /MISSI/ A set of MISSI X.509 public-key certificates that\r\n have the same subject DN, together with their associated private\r\n keys and usage specifications, that is stored on a FORTEZZA PC\r\n card to support a role played by the card's user.\r\n Tutorial: When a card's user selects a personality to use in a\r\n FORTEZZA-aware application, the data determines behavior traits\r\nShirey Informational [Page 221]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n (the personality) of the application. A card's user may have\r\n multiple personalities on the card. Each has a \"personality\r\n label\", a user-friendly character string that applications can\r\n display to the user for selecting or changing the personality to\r\n be used. For example, a military user's card might contain three\r\n personalities: GENERAL HALFTRACK, COMMANDER FORT SWAMPY, and NEW\r\n YEAR'S EVE PARTY CHAIRMAN. Each personality includes one or more\r\n certificates of different types (such as DSA versus RSA), for\r\n different purposes (such as digital signature versus encryption),\r\n or with different authorizations.\r\n $ personnel authentication system string (PASS)\r\n (N) See: Tutorial under \"personal identification number\".\r\n $ personnel security\r\n (I) Procedures to ensure that persons who access a system have\r\n proper clearance, authorization, and need-to-know as required by\r\n the system's security policy. (See: security architecture.)\r\n $ PGP(trademark)\r\n (O) See: Pretty Good Privacy(trademark).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 264 of 436\n\n$ phase 1 negotiation\r\n $ phase 2 negotiation\r\n (I) /ISAKMP/ See: secondary definition under \"Internet Security\r\n Association and Key Management Protocol\".\r\n $ phishing\r\n (D) /slang/ A technique for attempting to acquire sensitive data,\r\n such as bank account numbers, through a fraudulent solicitation in\r\n email or on a Web site, in which the perpetrator masquerades as a\r\n legitimate business or reputable person. (See: social\r\n engineering.)\r\n Derivation: Possibly from \"phony fishing\"; the solicitation\r\n usually involves some kind of lure or bait to hook unwary\r\n recipients. (Compare: phreaking.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is not listed\r\n in most dictionaries and could confuse international readers.\r\n (See: Deprecated Usage under \"Green Book\".)\r\n $ Photuris\r\n (I) A UDP-based, key establishment protocol for session keys,\r\n designed for use with the IPsec protocols AH and ESP. Superseded\r\n by IKE.\r\nShirey Informational [Page 222]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ phreaking\r\n (D) A contraction of \"telephone breaking\". An attack on or\r\n penetration of a telephone system or, by extension, any other\r\n communication or information system. [Raym]\r\n Deprecated Term: IDOCs SHOULD NOT use this contraction; it is not\r\n listed in most dictionaries and could confuse international\r\n readers. (See: Deprecated Usage under \"Green Book\".)\r\n $ physical destruction\r\n (I) /threat action/ See: secondary definition under\r\n \"incapacitation\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 265 of 436\n\n$ physical security\r\n (I) Tangible means of preventing unauthorized physical access to a\r\n system. Examples: Fences, walls, and other barriers; locks, safes,\r\n and vaults; dogs and armed guards; sensors and alarm bells.\r\n [FP031, R1455] (See: security architecture.)\r\n $ piggyback attack\r\n (I) A form of active wiretapping in which the attacker gains\r\n access to a system via intervals of inactivity in another user's\r\n legitimate communication connection. Sometimes called a \"between-\r\n the-lines\" attack. (See: hijack attack, man-in-the-middle attack.)\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the term could confuse international\r\n readers.\r\n $ PIN\r\n (I) See: personal identification number.\r\n $ ping of death\r\n (D) A denial-of-service attack that sends an improperly large ICMP\r\n echo request packet (a \"ping\") with the intent of causing the\r\n destination system to fail. (See: ping sweep, teardrop.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; instead, use\r\n \"ping packet overflow attack\" or some other term that is specific\r\n with regard to the attack mechanism.\r\n Tutorial: This attack seeks to exploit an implementation\r\n vulnerability. The IP specification requires hosts to be prepared\r\n to accept datagrams of up to 576 octets, but also permits IP\r\n datagrams to be up to 65,535 octets long. If an IP implementation\r\n does not properly handle very long IP packets, the ping packet may\r\n overflow the input buffer and cause a fatal system error.\r\nShirey Informational [Page 223]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ ping sweep\r\n (I) An attack that sends ICMP echo requests (\"pings\") to a range\r\n of IP addresses, with the goal of finding hosts that can be probed\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 266 of 436\n\nfor vulnerabilities. (See: ping of death. Compare: port scan.)\r\n $ PKCS\r\n (N) See: Public-Key Cryptography Standards.\r\n $ PKCS #5\r\n (N) A standard [PKC05] (see: RFC 2898) from the PKCS series;\r\n defines a method for encrypting an octet string with a secret key\r\n derived from a password.\r\n Tutorial: Although the method can be used for arbitrary octet\r\n strings, its intended primary application in public-key\r\n cryptography is for encrypting private keys when transferring them\r\n from one computer system to another, as described in PKCS #8.\r\n $ PKCS #7\r\n (N) A standard [PKC07] (see: RFC 2315) from the PKCS series;\r\n defines a syntax for data that may have cryptography applied to\r\n it, such as for digital signatures and digital envelopes. (See:\r\n CMS.)\r\n $ PKCS #10\r\n (N) A standard [PKC10] (see: RFC 2986) from the PKCS series;\r\n defines a syntax for certification requests. (See: certification\r\n request.)\r\n Tutorial: A PKCS #10 request contains a DN and a public key, and\r\n may contain other attributes, and is signed by the entity making\r\n the request. The request is sent to a CA, who converts it to an\r\n X.509 public-key certificate (or some other form), and returns it,\r\n possibly in PKCS #7 format.\r\n $ PKCS #11\r\n (N) A standard [PKC11] from the PKCS series; defines CAPI called\r\n \"Cryptoki\" for devices that hold cryptographic information and\r\n perform cryptographic functions.\r\n $ PKI\r\n (I) See: public-key infrastructure.\r\n $ PKINIT\r\n (I) Abbreviation for \"Public Key Cryptography for Initial\r\n Authentication in Kerberos\" (RFC 4556). (See: Tutorial under\r\n \"Kerberos\".)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 267 of 436\n\nShirey Informational [Page 224]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ PKIX\r\n 1a. (I) A contraction of \"Public-Key Infrastructure (X.509)\", the\r\n name of the IETF working group that is specifying an architecture\r\n [R3280] and set of protocols [R4210] to provide X.509-based PKI\r\n services for the Internet.\r\n 1b. (I) A collective name for that Internet PKI architecture and\r\n associated set of protocols.\r\n Tutorial: The goal of PKIX is to facilitate the use of X.509\r\n public-key certificates in multiple Internet applications and to\r\n promote interoperability between different implementations that\r\n use those certificates. The resulting PKI is intended to provide a\r\n framework that supports a range of trust and hierarchy\r\n environments and a range of usage environments. PKIX specifies (a)\r\n profiles of the v3 X.509 public-key certificate standards and the\r\n v2 X.509 CRL standards for the Internet, (b) operational protocols\r\n used by relying parties to obtain information such as certificates\r\n or certificate status, (c) management protocols used by system\r\n entities to exchange information needed for proper management of\r\n the PKI, and (d) information about certificate policies and CPSs,\r\n covering the areas of PKI security not directly addressed in the\r\n rest of PKIX.\r\n $ plain text\r\n 1. (I) /noun/ Data that is input to an encryption process. (See:\r\n plaintext. Compare: cipher text, clear text.)\r\n 2. (D) /noun/ Synonym for \"clear text\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"clear text\". Sometimes plain text that is input to an\r\n encryption operation is clear text, but other times plain text is\r\n cipher text that was output from a previous encryption operation.\r\n (See: superencryption.)\r\n $ plaintext\r\n 1. (O) /noun/ Synonym for \"plain text\".\r\n 2. (I) /adjective/ Referring to plain text. Usage: Commonly used\r\n instead of \"plain-text\". (Compare: ciphertext, cleartext.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 268 of 436\n\n3. (D) /noun/ Synonym for \"cleartext\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"cleartext\". Cleartext data is, by definition, not encrypted;\r\n but plaintext data that is input to an encryption operation may be\r\nShirey Informational [Page 225]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n cleartext data or may be ciphertext data that was output from a\r\n previous encryption operation. (See: superencryption.)\r\n $ PLI\r\n (I) See: Private Line Interface.\r\n $ PMA\r\n (N) See: policy management authority.\r\n $ Point-to-Point Protocol (PPP)\r\n (I) An Internet Standard protocol (RFC 1661) for encapsulation and\r\n full-duplex transportation of protocol data packets in OSIRM Layer\r\n 3 over an OSIRM Layer 2 link between two peers, and for\r\n multiplexing different Layer 3 protocols over the same link.\r\n Includes optional negotiation to select and use a peer entity\r\n authentication protocol to authenticate the peers to each other\r\n before they exchange Layer 3 data. (See: CHAP, EAP, PAP.)\r\n $ Point-to-Point Tunneling Protocol (PPTP)\r\n (I) An Internet client-server protocol (RFC 2637) (originally\r\n developed by Ascend and Microsoft) that enables a dial-up user to\r\n create a virtual extension of the dial-up link across a network by\r\n tunneling PPP over IP. (See: L2TP.)\r\n Tutorial: PPP can encapsulate any IPS Network Interface Layer\r\n protocol or OSIRM Layer 3 protocol. Therefore, PPTP does not\r\n specify security services; it depends on protocols above and below\r\n it to provide any needed security. PPTP makes it possible to\r\n divorce the location of the initial dial-up server (i.e., the PPTP\r\n Access Concentrator, the client, which runs on a special-purpose\r\n host) from the location at which the dial-up protocol (PPP)\r\n connection is terminated and access to the network is provided\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 269 of 436\n\n(i.e., at the PPTP Network Server, which runs on a general-purpose\r\n host).\r\n $ policy\r\n 1a. (I) A plan or course of action that is stated for a system or\r\n organization and is intended to affect and direct the decisions\r\n and deeds of that entity's components or members. (See: security\r\n policy.)\r\n 1b. (O) A definite goal, course, or method of action to guide and\r\n determine present and future decisions, that is implemented or\r\n executed within a particular context, such as within a business\r\n unit. [R3198]\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use \"policy\" as an\r\n abbreviation of either \"security policy\" or \"certificate policy\".\r\nShirey Informational [Page 226]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Instead, to avoid misunderstanding, use a fully qualified term, at\r\n least at the point of first usage.\r\n Tutorial: The introduction of new technology to replace\r\n traditional systems can result in new systems being deployed\r\n without adequate policy definition and before the implications of\r\n the new technology are fully understand. In some cases, it can be\r\n difficult to establish policies for new technology before the\r\n technology has been operationally tested and evaluated. Thus,\r\n policy changes tend to lag behind technological changes, such that\r\n either old policies impede the technical innovation, or the new\r\n technology is deployed without adequate policies to govern its\r\n use.\r\n When new technology changes the ways that things are done, new\r\n \"procedures\" must be defined to establish operational guidelines\r\n for using the technology and achieving satisfactory results, and\r\n new \"practices\" must be established for managing new systems and\r\n monitoring results. Practices and procedures are more directly\r\n coupled to actual systems and business operations than are\r\n polices, which tend to be more abstract.\r\n - \"Practices\" define how a system is to be managed and what\r\n controls are in place to monitor the system and detect abnormal\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 270 of 436\n\nbehavior or quality problems. Practices are established to\r\n ensure that a system is managed in compliance with stated\r\n policies. System audits are primarily concerned with whether or\r\n not practices are being followed. Auditors evaluate the\r\n controls to make sure they conform to accepted industry\r\n standards, and then confirm that controls are in place and that\r\n control measurements are being gathered. Audit trails are\r\n examples of control measurements that are recorded as part of\r\n system operations.\r\n - \"Procedures\" define how a system is operated, and relate\r\n closely to issues of what technology is used, who the operators\r\n are, and how the system is deployed physically. Procedures\r\n define both normal and abnormal operating circumstances.\r\n - For every control defined by a practice statement, there should\r\n be corresponding procedures to implement the control and\r\n provide ongoing measurement of the control parameters.\r\n Conversely, procedures require management practices to insure\r\n consistent and correct operational behavior.\r\n $ policy approval authority\r\n (D) /PKI/ Synonym for \"policy management authority\". [PAG]\r\n Deprecated Term: IDOCs SHOULD NOT use this term as synonym for\r\n \"policy management authority\". The term suggests a limited,\r\n passive role that is not typical of PMAs.\r\nShirey Informational [Page 227]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ policy approving authority (PAA)\r\n (O) /MISSI/ The top-level signing authority of a MISSI\r\n certification hierarchy. The term refers both to that\r\n authoritative office or role and to the person who plays that\r\n role. (See: policy management authority, root registry.)\r\n Tutorial: A MISSI PAA (a) registers MISSI PCAs and signs their\r\n X.509 public-key certificates, (b) issues CRLs but does not issue\r\n a CKL, and (c) may issue cross-certificates to other PAAs.\r\n $ policy authority\r\n (D) /PKI/ Synonym for \"policy management authority\". [PAG]\r\n Deprecated Term: IDOCs SHOULD NOT use this term as synonym for\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 271 of 436\n\n\"policy management authority\". The term is unnecessarily vague and\r\n thus may be confused with other PKI entities, such as CAs and RAs,\r\n that enforce of apply various aspects of PKI policy.\r\n $ policy certification authority (Internet PCA)\r\n (I) An X.509-compliant CA at the second level of the Internet\r\n certification hierarchy, under the IPRA. Each PCA operates under\r\n its published security policy (see: certificate policy, CPS) and\r\n within constraints established by the IPRA for all PCAs. [R1422].\r\n (See: policy creation authority.)\r\n $ policy creation authority (MISSI PCA)\r\n (O) /MISSI/ The second level of a MISSI certification hierarchy;\r\n the administrative root of a security policy domain of MISSI users\r\n and other, subsidiary authorities. The term refers both to that\r\n authoritative office or role and to the person who fills that\r\n office. (See: policy certification authority.)\r\n Tutorial: A MISSI PCA's certificate is issued by a PAA. The PCA\r\n registers the CAs in its domain, defines their configurations, and\r\n issues their X.509 public-key certificates. (The PCA may also\r\n issue certificates for SCAs, ORAs, and other end entities, but a\r\n PCA does not usually do this.) The PCA periodically issues CRLs\r\n and CKLs for its domain.\r\n $ policy management authority (PMA)\r\n (I) /PKI/ A person, role, or organization within a PKI that is\r\n responsible for (a) creating or approving the content of the\r\n certificate policies and CPSs that are used in the PKI; (b)\r\n ensuring the administration of those policies; and (c) approving\r\n any cross-certification or interoperability agreements with CAs\r\n external to the PKI and any related policy mappings. The PMA may\r\n also be the accreditor for the PKI as a whole or for some of its\r\nShirey Informational [Page 228]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n components or applications. [DoD9, PAG] (See: policy approving\r\n authority.)\r\n Example: In the U.S. Department of Defense, an organization called\r\n the Policy Management Authority is responsible for DoD PKI [DoD9].\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 272 of 436\n\n$ policy mapping\r\n (I) \"Recognizing that, when a CA in one domain certifies a CA in\r\n another domain, a particular certificate policy in the second\r\n domain may be considered by the authority of the first domain to\r\n be equivalent (but not necessarily identical in all respects) to a\r\n particular certificate policy in the first domain.\" [X509]\r\n $ policy rule\r\n (I) A building block of a security policy; it (a) defines a set of\r\n system conditions and (b) specifies a set of system actions that\r\n are to be performed if those conditions occur. [R3198]\r\n $ POP3\r\n (I) See: Post Office Protocol, version 3.\r\n $ POP3 APOP\r\n (I) A POP3 command (better described as a transaction type, or\r\n subprotocol) by which a POP3 client optionally uses a keyed hash\r\n (based on MD5) to authenticate itself to a POP3 server and,\r\n depending on the server implementation, to protect against replay\r\n attacks. (See: CRAM, POP3 AUTH, IMAP4 AUTHENTICATE.)\r\n Tutorial: The server includes a unique time stamp in its greeting\r\n to the client. The subsequent APOP command sent by the client to\r\n the server contains the client's name and the hash result of\r\n applying MD5 to a string formed from both the time stamp and a\r\n shared secret value that is known only to the client and the\r\n server. APOP was designed to provide an alternative to using\r\n POP3's USER and PASS (i.e., password) command pair, in which the\r\n client sends a cleartext password to the server.\r\n $ POP3 AUTH\r\n (I) A POP3 command [R1734] (better described as a transaction\r\n type, or subprotocol) by which a POP3 client optionally proposes a\r\n mechanism to a POP3 server to authenticate the client to the\r\n server and provide other security services. (See: POP3 APOP, IMAP4\r\n AUTHENTICATE.)\r\n Tutorial: If the server accepts the proposal, the command is\r\n followed by performing a challenge-response authentication\r\n protocol and, optionally, negotiating a protection mechanism for\r\nShirey Informational [Page 229]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 273 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n subsequent POP3 interactions. The security mechanisms used by POP3\r\n AUTH are those used by IMAP4.\r\n $ port scan\r\n (I) A technique that sends client requests to a range of service\r\n port addresses on a host. (See: probe. Compare: ping sweep.)\r\n Tutorial: A port scan can be used for pre-attack surveillance,\r\n with the goal of finding an active port and subsequently\r\n exploiting a known vulnerability of that port's service. A port\r\n scan can also be used as a flooding attack.\r\n $ positive authorization\r\n (I) The principle that a security architecture should be designed\r\n so that access to system resources is permitted only when\r\n explicitly granted; i.e., in the absence of an explicit\r\n authorization that grants access, the default action shall be to\r\n refuse access. (See: authorization, access.)\r\n $ POSIX\r\n (N) Portable Operating System Interface for Computer Environments,\r\n a standard [FP151, I9945] (originally IEEE Standard P1003.1) that\r\n defines an operating system interface and environment to support\r\n application portability at the source code level. It is intended\r\n to be used by both application developers and system implementers.\r\n Tutorial: P1003.1 supports security functionality like that on\r\n most UNIX systems, including discretionary access control and\r\n privileges. IEEE Draft Standard P1003.6 specifies additional\r\n functionality not provided in the base standard, including (a)\r\n discretionary access control, (b) audit trail mechanisms, (c)\r\n privilege mechanisms, (d) mandatory access control, and (e)\r\n information label mechanisms.\r\n $ Post Office Protocol, version 3 (POP3)\r\n (I) An Internet Standard protocol (RFC 1939) by which a client\r\n workstation can dynamically access a mailbox on a server host to\r\n retrieve mail messages that the server has received and is holding\r\n for the client. (See: IMAP4.)\r\n Tutorial: POP3 has mechanisms for optionally authenticating a\r\n client to a server and providing other security services. (See:\r\n POP3 APOP, POP3 AUTH.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 274 of 436\n\n$ PPP\r\n (I) See: Point-to-Point Protocol.\r\nShirey Informational [Page 230]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ PPTP\r\n (I) See: Point-to-Point Tunneling Protocol.\r\n $ preauthorization\r\n (N) /PKI/ A CAW feature that enables certification requests to be\r\n automatically validated against data provided in advance to the CA\r\n by an authorizing entity.\r\n $ precedence\r\n 1. (I) /information system/ A ranking assigned to events or data\r\n objects that determines the relative order in which they are\r\n processed.\r\n 2. (N) /communication system/ A designation assigned to a\r\n communication (i.e., packet, message, data stream, connection,\r\n etc.) by the originator to state the importance or urgency of that\r\n communication versus other communications, and thus indicate to\r\n the transmission system the relative order of handling, and\r\n indicate to the receiver the order in which the communication is\r\n to be noted. [F1037] (See: availability, critical, preemption.)\r\n Example: The \"Precedence\" subfield of the \"Type of Service\" field\r\n of the IPv4 header supports the following designations (in\r\n descending order of importance): 111 Network Control, 110\r\n Internetwork Control, 101 CRITIC/ECP (Critical Intelligence\r\n Communication/Emergency Command Precedence), 100 Flash Override,\r\n 011 Flash, 010 Immediate, 001 Priority, and 000 Routine. These\r\n designations were adopted from U.S. DoD systems that existed\r\n before ARPANET.\r\n $ preemption\r\n (N) The seizure, usually automatic, of system resources that are\r\n being used to serve a lower-precedence communication, in order to\r\n serve immediately a higher-precedence communication. [F1037]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 275 of 436\n\n$ Pretty Good Privacy(trademark) (PGP(trademark))\r\n (O) Trademarks of Network Associates, Inc., referring to a\r\n computer program (and related protocols) that uses cryptography to\r\n provide data security for electronic mail and other applications\r\n on the Internet. (Compare: DKIM, MOSS, MSP, PEM, S/MIME.)\r\n Tutorial: PGP encrypts messages with a symmetric algorithm\r\n (originally, IDEA in CFB mode), distributes the symmetric keys by\r\n encrypting them with an asymmetric algorithm (originally, RSA),\r\n and creates digital signatures on messages with a cryptographic\r\n hash and an asymmetric encryption algorithm (originally, MD5 and\r\n RSA). To establish ownership of public keys, PGP depends on the\r\n \"web of trust\".\r\nShirey Informational [Page 231]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ prevention\r\n (I) See: secondary definition under \"security\".\r\n $ primary account number (PAN)\r\n (O) /SET/ \"The assigned number that identifies the card issuer and\r\n cardholder. This account number is composed of an issuer\r\n identification number, an individual account number\r\n identification, and an accompanying check digit as defined by ISO\r\n 7812-1985.\" [SET2, I7812] (See: bank identification number.)\r\n Tutorial: The PAN is embossed, encoded, or both on a magnetic-\r\n strip-based credit card. The PAN identifies the issuer to which a\r\n transaction is to be routed and the account to which it is to be\r\n applied unless specific instructions indicate otherwise. The\r\n authority that assigns the BIN part of the PAN is the American\r\n Bankers Association.\r\n $ principal\r\n (I) A specific identity claimed by a user when accessing a system.\r\n Usage: Usually understood to be an identity that is registered in\r\n and authenticated by the system; equivalent to the notion of login\r\n account identifier. Each principal is normally assigned to a\r\n single user, but a single user may be assigned (or attempt to use)\r\n more than one principal. Each principal can spawn one or more\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 276 of 436\n\nsubjects, but each subject is associated with only one principal.\r\n (Compare: role, subject, user.)\r\n (I) /Kerberos/ A uniquely identified (i.e., uniquely named) client\r\n or server instance that participates in a network communication.\r\n $ priority\r\n (I) /information system/ Precedence for processing an event or\r\n data object, determined by security importance or other factors.\r\n (See: precedence.)\r\n $ privacy\r\n 1. (I) The right of an entity (normally a person), acting in its\r\n own behalf, to determine the degree to which it will interact with\r\n its environment, including the degree to which the entity is\r\n willing to share its personal information with others. (See:\r\n HIPAA, personal information, Privacy Act of 1974. Compare:\r\n anonymity, data confidentiality.) [FP041]\r\n 2. (O) \"The right of individuals to control or influence what\r\n information related to them may be collected and stored and by\r\n whom and to whom that information may be disclosed.\" [I7498-2]\r\nShirey Informational [Page 232]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 3. (D) Synonym for \"data confidentiality\".\r\n Deprecated Definition: IDOCs SHOULD NOT use this term as a synonym\r\n for \"data confidentiality\" or \"data confidentiality service\",\r\n which are different concepts. Privacy is a reason for security\r\n rather than a kind of security. For example, a system that stores\r\n personal data needs to protect the data to prevent harm,\r\n embarrassment, inconvenience, or unfairness to any person about\r\n whom data is maintained, and to protect the person's privacy. For\r\n that reason, the system may need to provide data confidentiality\r\n service.\r\n Tutorial: The term \"privacy\" is used for various separate but\r\n related concepts, including bodily privacy, territorial privacy,\r\n personal information privacy, and communication privacy. IDOCs are\r\n expected to address only communication privacy, which in this\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 277 of 436\n\nGlossary is defined primarily by \"data confidentiality\" and\r\n secondarily by \"data integrity\".\r\n IDOCs are not expected to address information privacy, but this\r\n Glossary provides definition 1 for that concept because personal\r\n information privacy is often confused with communication privacy.\r\n IDOCs are not expected to address bodily privacy or territorial\r\n privacy, and this Glossary does not define those concepts because\r\n they are not easily confused with communication privacy.\r\n $ Privacy Act of 1974\r\n (O) A U.S. Federal law (Section 552a of Title 5, United States\r\n Code) that seeks to balance the U.S. Government's need to maintain\r\n data about individuals with the rights of individuals to be\r\n protected against unwarranted invasions of their privacy stemming\r\n from federal agencies' collection, maintenance, use, and\r\n disclosure of personal data. (See: privacy.)\r\n Tutorial: In 1974, the U.S. Congress was concerned with the\r\n potential for abuses that could arise from the Government's\r\n increasing use of computers to store and retrieve personal data.\r\n Therefore, the Act has four basic policy objectives:\r\n - To restrict disclosure of personally identifiable records\r\n maintained by Federal agencies.\r\n - To grant individuals increased rights of access to Federal\r\n agency records maintained on themselves.\r\n - To grant individuals the right to seek amendment of agency\r\n records maintained on themselves upon a showing that the\r\n records are not accurate, relevant, timely, or complete.\r\n - To establish a code of \"fair information practices\" that\r\n requires agencies to comply with statutory norms for\r\n collection, maintenance, and dissemination of records.\r\nShirey Informational [Page 233]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Privacy Enhanced Mail (PEM)\r\n (I) An Internet protocol to provide data confidentiality, data\r\n integrity, and data origin authentication for electronic mail.\r\n [R1421, R1422]. (Compare: DKIM, MOSS, MSP, PGP, S/MIME.)\r\n Tutorial: PEM encrypts messages with a symmetric algorithm\r\n (originally, DES in CBC mode), provides distribution for the\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 278 of 436\n\nsymmetric keys by encrypting them with an asymmetric algorithm\r\n (originally, RSA), and signs messages with an asymmetric\r\n encryption algorithm over a cryptographic hash (originally, RSA\r\n over either MD2 or MD5). To establish ownership of public keys,\r\n PEM uses a certification hierarchy, with X.509 public-key\r\n certificates and X.509 CRLs that are signed with an asymmetric\r\n encryption algorithm over a cryptographic hash (originally, RSA\r\n over MD2).\r\n PEM is designed to be compatible with a wide range of key\r\n management methods, but is limited to specifying security services\r\n only for text messages and, like MOSS, has not been widely\r\n implemented in the Internet.\r\n $ private component\r\n (I) Synonym for \"private key\".\r\n Deprecated Usage: In most cases, IDOCs SHOULD NOT use this term;\r\n instead, to avoid confusing readers, use \"private key\". However,\r\n the term MAY be used when discussing a key pair; e.g., \"A key pair\r\n has a public component and a private component.\"\r\n $ private extension\r\n (I) See: secondary definition under \"extension\".\r\n $ private key\r\n 1. (I) The secret component of a pair of cryptographic keys used\r\n for asymmetric cryptography. (See: key pair, public key, secret\r\n key.)\r\n 2. (O) In a public key cryptosystem, \"that key of a user's key\r\n pair which is known only by that user.\" [X509]\r\n $ Private Line Interface (PLI)\r\n (I) The first end-to-end packet encryption system for a computer\r\n network, developed by BBN starting in 1975 for the U.S. DoD,\r\n incorporating U.S. Government-furnished, military-grade COMSEC\r\n equipment (TSEC/KG-34). [B1822] (Compare: IPLI.)\r\nShirey Informational [Page 234]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 279 of 436\n\n$ privilege\r\n 1a. (I) /access control/ A synonym for \"authorization\". (See\r\n authorization. Compare: permission.)\r\n 1b. (I) /computer platform/ An authorization to perform a\r\n security-relevant function in the context of a computer's\r\n operating system.\r\n $ privilege management infrastructure\r\n (O) \"The infrastructure able to support the management of\r\n privileges in support of a comprehensive authorization service and\r\n in relationship with a\" PKI; i.e., processes concerned with\r\n attribute certificates. [X509]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term with this\r\n definition. This definition is vague, and there is no consensus on\r\n a more specific one.\r\n $ privileged process\r\n (I) A computer process that is authorized (and, therefore,\r\n trusted) to perform some security-relevant functions that ordinary\r\n processes are not. (See: privilege, trusted process.)\r\n $ privileged user\r\n (I) An user that has access to system control, monitoring, or\r\n administration functions. (See: privilege, /UNIX/ under \"root\",\r\n superuser, user.)\r\n Tutorial: Privileged users include the following types:\r\n - Users with near or complete control of a system, who are\r\n authorized to set up and administer user accounts, identifiers,\r\n and authentication information, or are authorized to assign or\r\n change other users' access to system resources.\r\n - Users that are authorized to change control parameters (e.g.,\r\n network addresses, routing tables, processing priorities) on\r\n routers, multiplexers, and other important equipment.\r\n - Users that are authorized to monitor or perform troubleshooting\r\n for a system's security functions, typically using special\r\n tools and features that are not available to ordinary users.\r\n $ probe\r\n (I) /verb/ A technique that attempts to access a system to learn\r\n something about the system. (See: port scan.)\r\n Tutorial: The purpose of a probe may be offensive, e.g., an\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 280 of 436\n\nattempt to gather information for circumventing the system's\r\n protections; or the purpose may be defensive, e.g., to verify that\r\n the system is working properly.\r\nShirey Informational [Page 235]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ procedural security\r\n (D) Synonym for \"administrative security\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n \"administrative security\". The term may be misleading because any\r\n type of security may involve procedures, and procedures may be\r\n either external to the system or internal. Instead, use\r\n \"administrative security\", \"communication security\", \"computer\r\n security\", \"emanations security\", \"personnel security\", \"physical\r\n security\", or whatever specific type is meant. (See: security\r\n architecture.)\r\n $ profile\r\n See: certificate profile, protection profile.\r\n $ proof-of-possession protocol\r\n (I) A protocol whereby a system entity proves to another that it\r\n possesses and controls a cryptographic key or other secret\r\n information. (See: zero-knowledge proof.)\r\n $ proprietary\r\n (I) Refers to information (or other property) that is owned by an\r\n individual or organization and for which the use is restricted by\r\n that entity.\r\n $ protected checksum\r\n (I) A checksum that is computed for a data object by means that\r\n protect against active attacks that would attempt to change the\r\n checksum to make it match changes made to the data object. (See:\r\n digital signature, keyed hash, Tutorial under \"checksum\".)\r\n $ protective packaging\r\n (N) \"Packaging techniques for COMSEC material that discourage\r\n penetration, reveal a penetration has occurred or was attempted,\r\n or inhibit viewing or copying of keying material prior to the time\r\n it is exposed for use.\" [C4009] (See: tamper-evident, tamper-https://www.ietf.org/rfc/rfc4949.txt\r\nPage 281 of 436\n\nresistant. Compare: QUADRANT.)\r\n $ protection authority\r\n (I) See: secondary definition under \"Internet Protocol Security\r\n Option\".\r\n $ protection level\r\n (N) /U.S. Government/ An indication of the trust that is needed in\r\n a system's technical ability to enforce security policy for\r\n confidentiality. (Compare: /system operation/ under \"mode of\r\n operation\".)\r\nShirey Informational [Page 236]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: An organization's security policy could define\r\n protection levels that are based on comparing (a) the sensitivity\r\n of information handled by a system to (b) the authorizations of\r\n users that receive information from the system without manual\r\n intervention and reliable human review. For each level, the policy\r\n could specify security features and assurances that must be\r\n included in any system that was intended to operate at that level.\r\n Example: Given some set of data objects that are classified at one\r\n or more hierarchical levels and in one or more non-hierarchical\r\n categories, the following table defines five protection levels for\r\n systems that would handle that data. Beginning with PL1 and\r\n evolving to PL5, each successive level would require stronger\r\n features and assurances to handle the dataset. (See: clearance,\r\n formal access approval, and need-to-know.)\r\n Lowest Clearance Formal Access Need-To-Know\r\n Among All Users Approval of Users of Users\r\n +-------------------+-------------------+-------------------+\r\n PL5 | Some user has no | [Does not matter.]| [Does not matter.]|\r\n High | clearance at all. | | |\r\n +-------------------+-------------------+-------------------+\r\n PL4 | All are cleared | [Does not matter.]| [Does not matter.]|\r\n | for some data. | | |\r\n +-------------------+-------------------+-------------------+\r\n PL3 | All are cleared | Some not approved | [Does not matter.]|\r\n | for all data. | for all data. | |\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 282 of 436\n\n+-------------------+-------------------+-------------------+\r\n PL2 | All are cleared | All are approved | Some don't need to|\r\n | for all data. | for all data. | to know all data. |\r\n +-------------------+-------------------+-------------------+\r\n PL1 | All are cleared | All are approved | All have a need |\r\n Low | for all data. | for all data. | to know all data. |\r\n +-------------------+-------------------+-------------------+\r\n Each of these protection levels can be viewed as being equivalent to\r\n one or more modes of system operation defined in this Glossary:\r\n - PL5 is equivalent to multilevel security mode.\r\n - PL4 is equivalent to either multilevel or compartmented\r\n security mode, depending on the details of users' clearances.\r\n - PL3 is equivalent to partitioned security mode.\r\n - PL2 is equivalent to system-high security mode.\r\n - PL1 is equivalent to dedicated security mode.\r\n $ protection profile\r\n (N) /Common Criteria/ An implementation-independent set of\r\n security requirements for a category of targets of evaluation that\r\nShirey Informational [Page 237]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n meet specific consumer needs. [CCIB] Example: [IDSAN]. (See:\r\n target of evaluation. Compare: certificate profile, package.)\r\n Tutorial: A protection profile (PP) is the kind of document used\r\n by consumers to specify functional requirements they want in a\r\n product, and a security target (ST) is the kind of document used\r\n by vendors to make functional claims about a product.\r\n A PP is intended to be a reusable statement of product security\r\n needs, which are known to be useful and effective, for a set of\r\n information technology security products that could be built. A PP\r\n contains a set of security requirements, preferably taken from the\r\n catalogs in Parts 2 and 3 of the Common Criteria, and should\r\n include an EAL. A PP could be developed by user communities,\r\n product developers, or any other parties interested in defining a\r\n common set of requirements.\r\n $ protection ring\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 283 of 436\n\n(I) One of a hierarchy of privileged operation modes of a system\r\n that gives certain access rights to processes authorized to\r\n operate in that mode. (See: Multics.)\r\n $ protective distribution system (PDS)\r\n (N) A wireline or fiber-optic communication system used to\r\n transmit cleartext classified information through an area of\r\n lesser classification or control. [N7003]\r\n $ protocol\r\n 1a. (I) A set of rules (i.e., formats and procedures) to implement\r\n and control some type of association (e.g., communication) between\r\n systems. Example: Internet Protocol.\r\n 1b. (I) A series of ordered computing and communication steps that\r\n are performed by two or more system entities to achieve a joint\r\n objective. [A9042]\r\n $ protocol control information (PCI)\r\n (N) See: secondary definition under \"protocol data unit\".\r\n $ protocol data unit (PDU)\r\n (N) A data packet that is defined for peer-to-peer transfers in a\r\n protocol layer.\r\n Tutorial: A PDU consists of two disjoint subsets of data: the SDU\r\n and the PCI. (Although these terms -- PDU, SDU, and PCI --\r\n originated in the OSIRM, they are also useful and permissible in\r\n an IPS context.)\r\nShirey Informational [Page 238]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - The \"service data unit\" (SDU) in a packet is data that the\r\n protocol transfers between peer protocol entities on behalf of\r\n the users of that layer's services. For Layers 1 through 6, the\r\n layer's users are peer protocol entities at a higher layer; for\r\n Layer 7, the users are application entities outside the scope\r\n of the OSIRM.\r\n - The \"protocol control information\" (PCI) in a packet is data\r\n that peer protocol entities exchange between themselves to\r\n control their joint operation of the layer.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 284 of 436\n\n$ protocol suite\r\n (I) A complementary collection of communication protocols used in\r\n a computer network. (See: IPS, OSI.)\r\n $ proxy\r\n 1. (I) A computer process that acts on behalf of a user or client.\r\n 2. (I) A computer process -- often used as, or as part of, a\r\n firewall -- that relays application transactions or a protocol\r\n between client and server computer systems, by appearing to the\r\n client to be the server and appearing to the server to be the\r\n client. (See: SOCKS.)\r\n Tutorial: In a firewall, a proxy server usually runs on a bastion\r\n host, which may support proxies for several applications and\r\n protocols (e.g., FTP, HTTP, and TELNET). Instead of a client in\r\n the protected enclave connecting directly to an external server,\r\n the internal client connects to the proxy server, which in turn\r\n connects to the external server. The proxy server waits for a\r\n request from inside the firewall, forwards the request to the\r\n server outside the firewall, gets the response, then sends the\r\n response back to the client. The proxy may be transparent to the\r\n clients, or they may need to connect first to the proxy server,\r\n and then use that association to also initiate a connection to the\r\n real server.\r\n Proxies are generally preferred over SOCKS for their ability to\r\n perform caching, high-level logging, and access control. A proxy\r\n can provide security service beyond that which is normally part of\r\n the relayed protocol, such as access control based on peer entity\r\n authentication of clients, or peer entity authentication of\r\n servers when clients do not have that ability. A proxy at OSIRM\r\n Layer 7 can also provide finer-grained security service than can a\r\n filtering router at Layer 3. For example, an FTP proxy could\r\n permit transfers out of, but not into, a protected network.\r\nShirey Informational [Page 239]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 285 of 436\n\n$ proxy certificate\r\n (I) An X.509 public-key certificate derived from an end-entity\r\n certificate, or from another proxy certificate, for the purpose of\r\n establishing proxies and delegating authorizations in the context\r\n of a PKI-based authentication system. [R3820]\r\n Tutorial: A proxy certificate has the following properties:\r\n - It contains a critical extension that (a) identifies it as a\r\n proxy certificate and (b) may contain a certification path\r\n length constraint and policy constraints.\r\n - It contains the public component of a key pair that is distinct\r\n from that associated with any other certificate.\r\n - It is signed by the private component of a key pair that is\r\n associated with an end-entity certificate or another proxy\r\n certificate.\r\n - Its associated private key can be used to sign only other proxy\r\n certificates (not end-entity certificates).\r\n - Its \"subject\" DN is derived from its \"issuer\" DN and is unique.\r\n - Its \"issuer\" DN is the \"subject\" DN of an end-entity\r\n certificate or another proxy certificate.\r\n $ pseudorandom\r\n (I) A sequence of values that appears to be random (i.e.,\r\n unpredictable) but is actually generated by a deterministic\r\n algorithm. (See: compression, random, random number generator.)\r\n $ pseudorandom number generator\r\n (I) See: secondary definition under \"random number generator\".\r\n $ public component\r\n (I) Synonym for \"public key\".\r\n Deprecated Usage: In most cases, IDOCs SHOULD NOT use this term;\r\n to avoid confusing readers, use \"private key\" instead. However,\r\n the term MAY be used when discussing a key pair; e.g., \"A key pair\r\n has a public component and a private component.\"\r\n $ public key\r\n 1. (I) The publicly disclosable component of a pair of\r\n cryptographic keys used for asymmetric cryptography. (See: key\r\n pair. Compare: private key.)\r\n 2. (O) In a public key cryptosystem, \"that key of a user's key\r\n pair which is publicly known.\" [X509]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 286 of 436\n\nShirey Informational [Page 240]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ public-key certificate\r\n 1. (I) A digital certificate that binds a system entity's\r\n identifier to a public key value, and possibly to additional,\r\n secondary data items; i.e., a digitally signed data structure that\r\n attests to the ownership of a public key. (See: X.509 public-key\r\n certificate.)\r\n 2. (O) \"The public key of a user, together with some other\r\n information, rendered unforgeable by encipherment with the private\r\n key of the certification authority which issued it.\" [X509]\r\n Tutorial: The digital signature on a public-key certificate is\r\n unforgeable. Thus, the certificate can be published, such as by\r\n posting it in a directory, without the directory having to protect\r\n the certificate's data integrity.\r\n $ public-key cryptography\r\n (I) Synonym for \"asymmetric cryptography\".\r\n $ Public-Key Cryptography Standards (PKCS)\r\n (N) A series of specifications published by RSA Laboratories for\r\n data structures and algorithms used in basic applications of\r\n asymmetric cryptography. [PKCS] (See: PKCS #5 through PKCS #11.)\r\n Tutorial: The PKCS were begun in 1991 in cooperation with industry\r\n and academia, originally including Apple, Digital, Lotus,\r\n Microsoft, Northern Telecom, Sun, and MIT. Today, the\r\n specifications are widely used, but they are not sanctioned by an\r\n official standards organization, such as ANSI, ITU-T, or IETF. RSA\r\n Laboratories retains sole decision-making authority over the PKCS.\r\n $ public-key forward secrecy (PFS)\r\n (I) For a key-agreement protocol based on asymmetric cryptography,\r\n the property that ensures that a session key derived from a set of\r\n long-term public and private keys will not be compromised if one\r\n of the private keys is compromised in the future. (See: Usage note\r\n and other discussion under \"perfect forward secrecy\".)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 287 of 436\n\n$ public-key Kerberos\r\n (I) See: Tutorial under \"Kerberos\", PKINIT.\r\n $ public-key infrastructure (PKI)\r\n 1. (I) A system of CAs (and, optionally, RAs and other supporting\r\n servers and agents) that perform some set of certificate\r\n management, archive management, key management, and token\r\n management functions for a community of users in an application of\r\n asymmetric cryptography. (See: hierarchical PKI, mesh PKI,\r\n security management infrastructure, trust-file PKI.)\r\nShirey Informational [Page 241]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /PKIX/ The set of hardware, software, people, policies, and\r\n procedures needed to create, manage, store, distribute, and revoke\r\n digital certificates based on asymmetric cryptography.\r\n Tutorial: The core PKI functions are (a) to register users and\r\n issue their public-key certificates, (b) to revoke certificates\r\n when required, and (c) to archive data needed to validate\r\n certificates at a much later time. Key pairs for data\r\n confidentiality may be generated (and perhaps escrowed) by CAs or\r\n RAs, but requiring a PKI client to generate its own digital\r\n signature key pair helps maintain system integrity of the\r\n cryptographic system, because then only the client ever possesses\r\n the private key it uses. Also, an authority may be established to\r\n approve or coordinate CPSs, which are security policies under\r\n which components of a PKI operate.\r\n A number of other servers and agents may support the core PKI, and\r\n PKI clients may obtain services from them, such as certificate\r\n validation services. The full range of such services is not yet\r\n fully understood and is evolving, but supporting roles may include\r\n archive agent, certified delivery agent, confirmation agent,\r\n digital notary, directory, key escrow agent, key generation agent,\r\n naming agent who ensures that issuers and subjects have unique\r\n identifiers within the PKI, repository, ticket-granting agent,\r\n time-stamp agent, and validation agent.\r\n $ purge\r\n 1. (I) Synonym for \"erase\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 288 of 436\n\n2. (O) /U.S. Government/ Use degaussing or other methods to render\r\n magnetically stored data unusable and irrecoverable by any means,\r\n including laboratory methods. [C4009] (Compare: /U.S. Government/\r\n erase.)\r\n $ QUADRANT\r\n (O) /U.S. Government/ Short name for technology and methods that\r\n protect cryptographic equipment by making the equipment tamper-\r\n resistant. [C4009] (Compare: protective packaging, TEMPEST.)\r\n Tutorial: Equipment cannot be made completely tamper-proof, but it\r\n can be made tamper-resistant or tamper-evident.\r\n $ qualified certificate\r\n (I) A public-key certificate that has the primary purpose of\r\n identifying a person with a high level of assurance, where the\r\n certificate meets some qualification requirements defined by an\r\n applicable legal framework, such as the European Directive on\r\n Electronic Signature. [R3739]\r\nShirey Informational [Page 242]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ quick mode\r\n (I) See: /IKE/ under \"mode\".\r\n $ RA\r\n (I) See: registration authority.\r\n $ RA domains\r\n (I) A feature of a CAW that allows a CA to divide the\r\n responsibility for certificate requests among multiple RAs.\r\n Tutorial: This ability might be used to restrict access to private\r\n authorization data that is provided with a certificate request,\r\n and to distribute the responsibility to review and approve\r\n certificate requests in high-volume environments. RA domains might\r\n segregate certificate requests according to an attribute of the\r\n certificate's subject, such as an organizational unit.\r\n $ RADIUS\r\n (I) See: Remote Authentication Dial-In User Service.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 289 of 436\n\n$ Rainbow Series\r\n (O) /COMPUSEC/ A set of more than 30 technical and policy\r\n documents with colored covers, issued by the NCSC, that discuss in\r\n detail the TCSEC and provide guidance for meeting and applying the\r\n criteria. (See: Green Book, Orange Book, Red Book, Yellow Book.)\r\n $ random\r\n (I) In essence, \"random\" means \"unpredictable\". [SP22, Knut,\r\n R4086] (See: cryptographic key, pseudorandom.)\r\n - \"Random sequence\": A sequence in which each successive value is\r\n obtained merely by chance and does not depend on the preceding\r\n values of the sequence. In a random sequence of bits, each bit\r\n is unpredictable; i.e., (a) the probability of each bit being a\r\n \"0\" or \"1\" is 1/2, and (b) the value of each bit is independent\r\n of any other bit in the sequence.\r\n - \"Random value\": An individual value that is unpredictable;\r\n i.e., each value in the total population of possibilities has\r\n equal probability of being selected.\r\n $ random number generator\r\n (I) A process that is invoked to generate a random sequence of\r\n values (usually a sequence of bits) or an individual random value.\r\n Tutorial: There are two basic types of generators. [SP22]\r\n - \"(True) random number generator\": It uses one or more non-\r\n deterministic bit sources (e.g., electrical circuit noise,\r\n timing of human processes such as key strokes or mouse\r\n movements, semiconductor quantum effects, and other physical\r\nShirey Informational [Page 243]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n phenomena) and a processing function that formats the bits, and\r\n it outputs a sequence of values that is unpredictable and\r\n uniformly distributed.\r\n - \"Pseudorandom number generator\": It uses a deterministic\r\n computational process (usually implemented by software) that\r\n has one or more inputs called \"seeds\", and it outputs a\r\n sequence of values that appears to be random according to\r\n specified statistical tests.\r\n $ RBAC\r\n (N) See: role-based access control, rule-based access control.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 290 of 436\n\nDeprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the abbreviation is ambiguous.\r\n $ RC2, RC4, RC6\r\n (N) See: Rivest Cipher #2, #4, #6.\r\n $ read\r\n (I) /security model/ A system operation that causes a flow of\r\n information from an object to a subject. (See: access mode.\r\n Compare: write.)\r\n $ realm\r\n (I) /Kerberos/ A domain consisting of a set of Kerberized clients,\r\n Kerberized application servers, and one or more Kerberos\r\n authentication servers and ticket-granting servers that support\r\n the clients and applications, all operating under the same\r\n security policy. (See: domain.)\r\n $ recovery\r\n 1. (I) /cryptography/ The process of learning or obtaining\r\n cryptographic data or plain text through cryptanalysis. (See: key\r\n recovery, data recovery.)\r\n 2a. (I) /system integrity/ The process of restoring a secure state\r\n in a system after there has been an accidental failure or a\r\n successful attack. (See: secondary definition under \"security\",\r\n system integrity.)\r\n 2b. (I) /system integrity/ The process of restoring an information\r\n system's assets and operation following damage or destruction.\r\n (See: contingency plan.)\r\n $ RED\r\n 1. (N) Designation for data that consists only of clear text, and\r\n for information system equipment items and facilities that handle\r\nShirey Informational [Page 244]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n clear text. Example: \"RED key\". (See: BCR, color change, RED/BLACK\r\n separation. Compare: BLACK.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 291 of 436\n\nDerivation: From the practice of marking equipment with colors to\r\n prevent operational errors.\r\n 2. (O) /U.S. Government/ Designation applied to information\r\n systems, and to associated areas, circuits, components, and\r\n equipment, \"in which unencrypted national security information is\r\n being processed.\" [C4009]\r\n $ RED/BLACK separation\r\n (N) An architectural concept for cryptographic systems that\r\n strictly separates the parts of a system that handle plain text\r\n (i.e., RED information) from the parts that handle cipher text\r\n (i.e., BLACK information). (See: BLACK, RED.)\r\n $ Red Book\r\n (D) /slang/ Synonym for \"Trusted Network Interpretation of the\r\n Trusted Computer System Evaluation Criteria\" [NCS05].\r\n Deprecated Term: IDOCs SHOULD NOT use this term. Instead, use the\r\n full proper name of the document or, in subsequent references, a\r\n more conventional abbreviation, e.g., TNI-TCSEC. (See: TCSEC,\r\n Rainbow Series, Deprecated Usage under \"Green Book\".)\r\n $ RED key\r\n (N) A cleartext key, which is usable in its present form (i.e., it\r\n does not need to be decrypted before being used). (See: RED.\r\n Compare: BLACK key.)\r\n $ reference monitor\r\n (I) \"An access control concept that refers to an abstract machine\r\n that mediates all accesses to objects by subjects.\" [NCS04] (See:\r\n security kernel.)\r\n Tutorial: This concept was described in the Anderson report. A\r\n reference monitor should be (a) complete (i.e., it mediates every\r\n access), (b) isolated (i.e., it cannot be modified by other system\r\n entities), and (c) verifiable (i.e., small enough to be subjected\r\n to analysis and tests to ensure that it is correct).\r\n $ reflection attack\r\n (I) An attack in which a valid data transmission is replayed to\r\n the originator by an attacker who intercepts the original\r\n transmission. (Compare: indirect attack, replay attack.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 292 of 436\n\nShirey Informational [Page 245]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ reflector attack\r\n (D) Synonym for \"indirect attack\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it could be\r\n confused with \"reflection attack\", which is a different concept.\r\n $ registered user\r\n (I) A system entity that is authorized to receive a system's\r\n products and services or otherwise access system resources. (See:\r\n registration, user.)\r\n $ registration\r\n 1. (I) /information system/ A system process that (a) initializes\r\n an identity (of a system entity) in the system, (b) establishes an\r\n identifier for that identity, (c) may associate authentication\r\n information with that identifier, and (d) may issue an identifier\r\n credential (depending on the type of authentication mechanism\r\n being used). (See: authentication information, credential,\r\n identifier, identity, identity proofing.)\r\n 2. (I) /PKI/ An administrative act or process whereby an entity's\r\n name and other attributes are established for the first time at a\r\n CA, prior to the CA issuing a digital certificate that has the\r\n entity's name as the subject. (See: registration authority.)\r\n Tutorial: Registration may be accomplished either directly, by the\r\n CA, or indirectly, by a separate RA. An entity is presented to the\r\n CA or RA, and the authority either records the name(s) claimed for\r\n the entity or assigns the entity's name(s). The authority also\r\n determines and records other attributes of the entity that are to\r\n be bound in a certificate (such as a public key or authorizations)\r\n or maintained in the authority's database (such as street address\r\n and telephone number). The authority is responsible, possibly\r\n assisted by an RA, for verifying the entity's identity and vetting\r\n the other attributes, in accordance with the CA's CPS.\r\n Among the registration issues that a CPS may address are the\r\n following [R3647]:\r\n - How a claimed identity and other attributes are verified.\r\n - How organization affiliation or representation is verified.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 293 of 436\n\n- What forms of names are permitted, such as X.500 DN, domain\r\n name, or IP address.\r\n - Whether names are required to be meaningful or unique, and\r\n within what domain.\r\n - How naming disputes are resolved, including the role of\r\n trademarks.\r\n - Whether certificates are issued to entities that are not\r\n persons.\r\nShirey Informational [Page 246]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - Whether a person is required to appear before the CA or RA, or\r\n can instead be represented by an agent.\r\n - Whether and how an entity proves possession of the private key\r\n matching a public key.\r\n $ registration authority (RA)\r\n 1. (I) An optional PKI entity (separate from the CAs) that does\r\n not sign either digital certificates or CRLs but has\r\n responsibility for recording or verifying some or all of the\r\n information (particularly the identities of subjects) needed by a\r\n CA to issue certificates and CRLs and to perform other certificate\r\n management functions. (See: ORA, registration.)\r\n 2. (I) /PKIX/ An optional PKI component, separate from the CA(s).\r\n The functions that the RA performs will vary from case to case but\r\n may include identity authentication and name assignment, key\r\n generation and archiving of key pairs, token distribution, and\r\n revocation reporting. [R4210]\r\n Tutorial: Sometimes, a CA may perform all certificate management\r\n functions for all end users for which the CA signs certificates.\r\n Other times, such as in a large or geographically dispersed\r\n community, it may be necessary or desirable to offload secondary\r\n CA functions and delegate them to an assistant, while the CA\r\n retains the primary functions (signing certificates and CRLs). The\r\n tasks that are delegated to an RA by a CA may include personal\r\n authentication, name assignment, token distribution, revocation\r\n reporting, key generation, and archiving.\r\n An RA is an optional PKI entity, separate from the CA, that is\r\n assigned secondary functions. The duties assigned to RAs vary from\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 294 of 436\n\ncase to case but may include the following:\r\n - Verifying a subject's identity, i.e., performing personal\r\n authentication functions.\r\n - Assigning a name to a subject. (See: distinguished name.)\r\n - Verifying that a subject is entitled to have the attributes\r\n requested for a certificate.\r\n - Verifying that a subject possesses the private key that matches\r\n the public key requested for a certificate.\r\n - Performing functions beyond mere registration, such as\r\n generating key pairs, distributing tokens, handling revocation\r\n reports, and archiving data. (Such functions may be assigned to\r\n a PKI component that is separate from both the CA and the RA.)\r\n 3. (O) /SET/ \"An independent third-party organization that\r\n processes payment card applications for multiple payment card\r\n brands and forwards applications to the appropriate financial\r\n institutions.\" [SET2]\r\nShirey Informational [Page 247]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ regrade\r\n (I) Deliberately change the security level (especially the\r\n hierarchical classification level) of information in an authorized\r\n manner. (See: downgrade, upgrade.)\r\n $ rekey\r\n (I) Change the value of a cryptographic key that is being used in\r\n an application of a cryptographic system. (See: certificate\r\n rekey.)\r\n Tutorial: Rekey is required at the end of a cryptoperiod or key\r\n lifetime.\r\n $ reliability\r\n (I) The ability of a system to perform a required function under\r\n stated conditions for a specified period of time. (Compare:\r\n availability, survivability.)\r\n $ reliable human review\r\n (I) Any manual, automated, or hybrid process or procedure that\r\n ensures that a human examines a digital object, such as text or an\r\n image, to determine whether the object may be permitted, according\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 295 of 436\n\nto some security policy, to be transferred across a controlled\r\n interface. (See: guard.)\r\n $ relying party\r\n (I) Synonym for \"certificate user\".\r\n Usage: Used in a legal context to mean a recipient of a\r\n certificate who acts in reliance on that certificate. (See: ABA\r\n Guidelines.)\r\n $ remanence\r\n (I) Residual information that can be recovered from a storage\r\n medium after clearing. (See: clear, magnetic remanence, purge.)\r\n $ Remote Authentication Dial-In User Service (RADIUS)\r\n (I) An Internet protocol [R2865] for carrying dial-in users'\r\n authentication information and configuration information between a\r\n shared, centralized authentication server (the RADIUS server) and\r\n a network access server (the RADIUS client) that needs to\r\n authenticate the users of its network access ports. (See: TACACS.)\r\n User presents authentication and possibly other information to the\r\n RADIUS client (e.g., health information regarding the user\r\n device).\r\nShirey Informational [Page 248]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: A user presents authentication information and possibly\r\n other information to the RADIUS client, and the client passes that\r\n information to the RADIUS server. The server authenticates the\r\n client using a shared secret value and checks the presented\r\n information, and then returns to the client all authorization and\r\n configuration information needed by the client to serve the user.\r\n $ renew\r\n See: certificate renewal.\r\n $ reordering\r\n (I) /packet/ See: secondary definition under \"stream integrity\r\n service\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 296 of 436\n\n$ replay attack\r\n (I) An attack in which a valid data transmission is maliciously or\r\n fraudulently repeated, either by the originator or by a third\r\n party who intercepts the data and retransmits it, possibly as part\r\n of a masquerade attack. (See: active wiretapping, fresh, liveness,\r\n nonce. Compare: indirect attack, reflection attack.)\r\n $ repository\r\n 1. (I) A system for storing and distributing digital certificates\r\n and related information (including CRLs, CPSs, and certificate\r\n policies) to certificate users. (Compare: archive, directory.)\r\n 2. (O) \"A trustworthy system for storing and retrieving\r\n certificates or other information relevant to certificates.\" [DSG]\r\n Tutorial: A certificate is published to those who might need it by\r\n putting it in a repository. The repository usually is a publicly\r\n accessible, on-line server. In the FPKI, for example, the expected\r\n repository is a directory that uses LDAP, but also may be an X.500\r\n Directory that uses DAP, or an HTTP server, or an FTP server that\r\n permits anonymous login.\r\n $ repudiation\r\n 1. (I) Denial by a system entity that was involved in an\r\n association (especially a communication association that transfers\r\n data) of having participated in the relationship. (See:\r\n accountability, non-repudiation service.)\r\n 2. (I) A type of threat action whereby an entity deceives another\r\n by falsely denying responsibility for an act. (See: deception.)\r\nShirey Informational [Page 249]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: This type of threat action includes the following subtypes:\r\n - False denial of origin: Action whereby an originator denies\r\n responsibility for sending data.\r\n - False denial of receipt: Action whereby a recipient denies\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 297 of 436\n\nreceiving and possessing data.\r\n 3. (O) /OSIRM/ \"Denial by one of the entities involved in a\r\n communication of having participated in all or part of the\r\n communication.\" [I7498-2]\r\n $ Request for Comment (RFC)\r\n 1. (I) One of the documents in the archival series that is the\r\n official channel for IDOCs and other publications of the Internet\r\n Engineering Steering Group, the Internet Architecture Board, and\r\n the Internet community in general. (RFC 2026, 2223) (See: Internet\r\n Standard.)\r\n 2. (D) A popularly misused synonym for a document on the Internet\r\n Standards Track, i.e., an Internet Standard, Draft Standard, or\r\n Proposed Standard. (See: Internet Standard.)\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 2 because many other types of documents also are\r\n published as RFCs.\r\n $ residual risk\r\n (I) The portion of an original risk or set of risks that remains\r\n after countermeasures have been applied. (Compare: acceptable\r\n risk, risk analysis.)\r\n $ restore\r\n See: card restore.\r\n $ reverse engineering\r\n (I) /threat action/ See: secondary definition under \"intrusion\".\r\n $ revocation\r\n See: certificate revocation.\r\n $ revocation date\r\n (N) /X.509/ In a CRL entry, a date-time field that states when the\r\n certificate revocation occurred, i.e., when the CA declared the\r\n digital certificate to be invalid. (See: invalidity date.)\r\n Tutorial: The revocation date may not resolve some disputes\r\n because, in the worst case, all signatures made during the\r\n validity period of the certificate may have to be considered\r\n invalid. However, it may be desirable to treat a digital signature\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 298 of 436\n\nShirey Informational [Page 250]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n as valid even though the private key used to sign was compromised\r\n after the signing. If more is known about when the compromise\r\n actually occurred, a second date-time, an \"invalidity date\", can\r\n be included in an extension of the CRL entry.\r\n $ revocation list\r\n See: certificate revocation list.\r\n $ revoke\r\n (I) See: certificate revocation.\r\n $ RFC\r\n (I) See: Request for Comment.\r\n $ Rijndael\r\n (N) A symmetric, block cipher that was designed by Joan Daemen and\r\n Vincent Rijmen as a candidate for the AES, and that won that\r\n competition. [Daem] (See: Advanced Encryption Standard.)\r\n $ risk\r\n 1. (I) An expectation of loss expressed as the probability that a\r\n particular threat will exploit a particular vulnerability with a\r\n particular harmful result. (See: residual risk.)\r\n 2. (O) /SET/ \"The possibility of loss because of one or more\r\n threats to information (not to be confused with financial or\r\n business risk).\" [SET2]\r\n Tutorial: There are four basic ways to deal with a risk [SP30]:\r\n - \"Risk avoidance\": Eliminate the risk by either countering the\r\n threat or removing the vulnerability. (Compare: \"avoidance\"\r\n under \"security\".)\r\n - \"Risk transference\": Shift the risk to another system or\r\n entity; e.g., buy insurance to compensate for potential loss.\r\n - \"Risk limitation\": Limit the risk by implementing controls that\r\n minimize resulting loss.\r\n - \"Risk assumption\": Accept the potential for loss and continue\r\n operating the system.\r\n $ risk analysis\r\n (I) An assessment process that systematically (a) identifies\r\n valuable system resources and threats to those resources, (b)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 299 of 436\n\nquantifies loss exposures (i.e., loss potential) based on\r\n estimated frequencies and costs of occurrence, and (c)\r\n (optionally) recommends how to allocate available resources to\r\n countermeasures so as to minimize total exposure. (See: risk\r\n management, business-case analysis. Compare: threat analysis.)\r\nShirey Informational [Page 251]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Usually, it is financially and technically infeasible to\r\n avoid or transfer all risks (see: \"first corollary\" of \"second\r\n law\" under \"Courtney's laws\"), and some residual risks will\r\n remain, even after all available countermeasures have been\r\n deployed (see: \"second corollary\" of \"second law\" under\r\n \"Courtney's laws\"). Thus, a risk analysis typically lists risks in\r\n order of cost and criticality, thereby determining where\r\n countermeasures should be applied first. [FP031, R2196]\r\n In some contexts, it is infeasible or inadvisable to attempt a\r\n complete or quantitative risk analysis because needed data, time,\r\n and expertise are not available. Instead, basic answers to\r\n questions about threats and risks may be already built into\r\n institutional security policies. For example, U.S. DoD policies\r\n for data confidentiality \"do not explicitly itemize the range of\r\n expected threats\" but instead \"reflect an operational approach ...\r\n by stating the particular management controls that must be used to\r\n achieve [confidentiality] ... Thus, they avoid listing threats,\r\n which would represent a severe risk in itself, and avoid the risk\r\n of poor security design implicit in taking a fresh approach to\r\n each new problem\". [NRC91]\r\n $ risk assumption\r\n (I) See: secondary definition under \"risk\".\r\n $ risk avoidance\r\n (I) See: secondary definition under \"risk\".\r\n $ risk limitation\r\n (I) See: secondary definition under \"risk\".\r\n $ risk management\r\n 1. (I) The process of identifying, measuring, and controlling\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 300 of 436\n\n(i.e., mitigating) risks in information systems so as to reduce\r\n the risks to a level commensurate with the value of the assets\r\n protected. (See: risk analysis.)\r\n 2. (I) The process of controlling uncertain events that may affect\r\n information system resources.\r\n 3. (O) \"The total process of identifying, controlling, and\r\n mitigating information system-related risks. It includes risk\r\n assessment; cost-benefit analysis; and the selection,\r\n implementation, test, and security evaluation of safeguards. This\r\n overall system security review considers both effectiveness and\r\n efficiency, including impact on the mission and constraints due to\r\n policy, regulations, and laws.\" [SP30]\r\nShirey Informational [Page 252]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ risk transference\r\n (I) See: secondary definition under \"risk\".\r\n $ Rivest Cipher #2 (RC2)\r\n (N) A proprietary, variable-key-length block cipher invented by\r\n Ron Rivest for RSA Data Security, Inc.\r\n $ Rivest Cipher #4 (RC4)\r\n (N) A proprietary, variable-key-length stream cipher invented by\r\n Ron Rivest for RSA Data Security, Inc.\r\n $ Rivest Cipher #6 (RC6)\r\n (N) A symmetric, block cipher with 128-bit or longer key length,\r\n developed by Ron Rivest for RSA Data Security, Inc. as a candidate\r\n for the AES.\r\n $ Rivest-Shamir-Adleman (RSA)\r\n (N) An algorithm for asymmetric cryptography, invented in 1977 by\r\n Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78].\r\n Tutorial: RSA uses exponentiation modulo the product of two large\r\n prime numbers. The difficulty of breaking RSA is believed to be\r\n equivalent to the difficulty of factoring integers that are the\r\n product of two large prime numbers of approximately equal size.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 301 of 436\n\nTo create an RSA key pair, randomly choose two large prime\r\n numbers, p and q, and compute the modulus, n = pq. Randomly choose\r\n a number e, the public exponent, that is less than n and\r\n relatively prime to (p-1)(q-1). Choose another number d, the\r\n private exponent, such that ed-1 evenly divides (p-1)(q-1). The\r\n public key is the set of numbers (n,e), and the private key is the\r\n set (n,d).\r\n It is assumed to be difficult to compute the private key (n,d)\r\n from the public key (n,e). However, if n can be factored into p\r\n and q, then the private key d can be computed easily. Thus, RSA\r\n security depends on the assumption that it is computationally\r\n difficult to factor a number that is the product of two large\r\n prime numbers. (Of course, p and q are treated as part of the\r\n private key, or else are destroyed after computing n.)\r\n For encryption of a message, m, to be sent to Bob, Alice uses\r\n Bob's public key (n,e) to compute m**e (mod n) = c. She sends c to\r\n Bob. Bob computes c**d (mod n) = m. Only Bob knows d, so only Bob\r\n can compute c**d (mod n) to recover m.\r\n To provide data origin authentication of a message, m, to be sent\r\n to Bob, Alice computes m**d (mod n) = s, where (d,n) is Alice's\r\nShirey Informational [Page 253]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n private key. She sends m and s to Bob. To recover the message that\r\n only Alice could have sent, Bob computes s**e (mod n) = m, where\r\n (e,n) is Alice's public key.\r\n To ensure data integrity in addition to data origin authentication\r\n requires extra computation steps in which Alice and Bob use a\r\n cryptographic hash function h (see: digital signature). Alice\r\n computes the hash value h(m) = v, and then encrypts v with her\r\n private key to get s. She sends m and s. Bob receives m' and s',\r\n either of which might have been changed from the m and s that\r\n Alice sent. To test this, he decrypts s' with Alice's public key\r\n to get v'. He then computes h(m') = v\". If v' equals v\", Bob is\r\n assured that m' is the same m that Alice sent.\r\n $ robustness\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 302 of 436\n\n(N) See: level of robustness.\r\n $ role\r\n 1. (I) A job function or employment position to which people or\r\n other system entities may be assigned in a system. (See: role-\r\n based access control. Compare: duty, billet, principal, user.)\r\n 2. (O) /Common Criteria/ A pre-defined set of rules establishing\r\n the allowed interactions between a user and the TOE.\r\n $ role-based access control\r\n (I) A form of identity-based access control wherein the system\r\n entities that are identified and controlled are functional\r\n positions in an organization or process. [Sand] (See:\r\n authorization, constraint, identity, principal, role.)\r\n Tutorial: Administrators assign permissions to roles as needed to\r\n perform functions in the system. Administrators separately assign\r\n user identities to roles. When a user accesses the system in an\r\n identity (for which the user has been registered) and initiates a\r\n session using a role (to which the user has been assigned), then\r\n the permissions that have been assigned to the role are available\r\n to be exercised by the user.\r\n The following diagram shows that role-based access control\r\n involves five different relationships: (a) administrators assign\r\n identities to roles, (b) administrators assign permissions to\r\n roles, (c) administrators assign roles to roles, (d) users select\r\n identities in sessions, and (e) users select roles in sessions.\r\n Security policies may define constraints on these assignments and\r\n selections.\r\nShirey Informational [Page 254]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n (c) Permission Inheritance Assignments (i.e., Role Hierarchy)\r\n [Constraints]\r\n +=====+\r\n | |\r\n (a) Identity v v (b) Permission\r\n +----------+ Assignments +-------+ Assignments +----------+\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 303 of 436\n\n|Identities|\u003c=============\u003e| Roles |\u003c=============\u003e|Permissions|\r\n +----------+ [Constraints] +-------+ [Constraints] +----------+\r\n | | ^ ^\r\n | | +-----------+ | | +---------------------+\r\n | | | +-------+ | | | | Legend |\r\n | +====\u003e|Session|=====+ | | |\r\n | | +-------+ | | | One-to-One |\r\n | | ... | | | =================== |\r\n | | +-------+ | | | |\r\n +========\u003e|Session|=========+ | One-to-Many |\r\n (d) Identity | +-------+ | (e) Role | ==================\u003e |\r\n Selections | | Selections | |\r\n [Constraints]| Access |[Constraints] | Many-to-Many |\r\n | Sessions | | \u003c=================\u003e |\r\n +-----------+ +---------------------+\r\n $ role certificate\r\n (I) An organizational certificate that is issued to a system\r\n entity that is a member of the set of users that have identities\r\n that are assigned to the same role. (See: role-based access\r\n control.)\r\n $ root, root CA\r\n 1. (I) /PKI/ A CA that is directly trusted by an end entity. (See:\r\n trust anchor, trusted CA.)\r\n 2. (I) /hierarchical PKI/ The CA that is the highest level (most\r\n trusted) CA in a certification hierarchy; i.e., the authority upon\r\n whose public key all certificate users base their validation of\r\n certificates, CRLs, certification paths, and other constructs.\r\n (See: top CA.)\r\n Tutorial: The root CA in a certification hierarchy issues public-\r\n key certificates to one or more additional CAs that form the\r\n second-highest level. Each of these CAs may issue certificates to\r\n more CAs at the third-highest level, and so on. To initialize\r\n operation of a hierarchical PKI, the root's initial public key is\r\n securely distributed to all certificate users in a way that does\r\n not depend on the PKI's certification relationships, i.e., by an\r\n out-of-band procedure. The root's public key may be distributed\r\n simply as a numerical value, but typically is distributed in a\r\n self-signed certificate in which the root is the subject. The\r\nShirey Informational [Page 255]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 304 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n root's certificate is signed by the root itself because there is\r\n no higher authority in a certification hierarchy. The root's\r\n certificate is then the first certificate in every certification\r\n path.\r\n 3. (I) /DNS/ The base of the tree structure that defines the name\r\n space for the Internet DNS. (See: domain name.)\r\n 4. (O) /MISSI/ A name previously used for a MISSI policy creation\r\n authority, which is not a root as defined above for general usage,\r\n but is a CA at the second level of the MISSI hierarchy,\r\n immediately subordinate to a MISSI policy approving authority.\r\n 5. (O) /UNIX/ A user account (a.k.a. \"superuser\") that has all\r\n privileges (including all security-related privileges) and thus\r\n can manage the system and its other user accounts.\r\n $ root certificate\r\n 1. (I) /PKI/ A certificate for which the subject is a root. (See:\r\n trust anchor certificate, trusted certificate.)\r\n 2. (I) /hierarchical PKI/ The self-signed public-key certificate\r\n at the top of a certification hierarchy.\r\n $ root key\r\n (I) /PKI/ A public key for which the matching private key is held\r\n by a root. (See: trust anchor key, trusted key.)\r\n $ root registry\r\n (O) /MISSI/ A name previously used for a MISSI PAA.\r\n $ ROT13\r\n (I) See: secondary definition under \"Caesar cipher\".\r\n $ router\r\n 1a. (I) /IP/ A networked computer that forwards IP packets that\r\n are not addressed to the computer itself. (Compare: host.)\r\n 1b. (I) /IPS/ A gateway that operates in the IPS Internet Layer to\r\n connect two or more subnetworks.\r\n 1c. (N) /OSIRM/ A computer that is a gateway between two networks\r\n at OSIRM Layer 3 and that relays and directs data packets through\r\n that internetwork. (Compare: bridge, proxy.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 305 of 436\n\n$ RSA\r\n (N) See: Rivest-Shamir-Adleman.\r\nShirey Informational [Page 256]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ rule\r\n See: policy rule.\r\n $ rule-based security policy\r\n (I) \"A security policy based on global rules [i.e., policy rules]\r\n imposed for all users. These rules usually rely on comparison of\r\n the sensitivity of the resource being accessed and the possession\r\n of corresponding attributes of users, a group of users, or\r\n entities acting on behalf of users.\" [I7498-2] (Compare: identity-\r\n based security policy, policy rule, RBAC.)\r\n $ rules of behavior\r\n (I) A body of security policy that has been established and\r\n implemented concerning the responsibilities and expected behavior\r\n of entities that have access to a system. (Compare: [R1281].)\r\n Tutorial: For persons employed by a corporation or government, the\r\n rules might cover such matters as working at home, remote access,\r\n use of the Internet, use of copyrighted works, use of system\r\n resources for unofficial purpose, assignment and limitation of\r\n system privileges, and individual accountability.\r\n $ S field\r\n (D) See: Security Level field.\r\n $ S-BGP\r\n (I) See: Secure BGP.\r\n $ S-HTTP\r\n (I) See: Secure Hypertext Transfer Protocol.\r\n $ S/Key\r\n (I) A security mechanism that uses a cryptographic hash function\r\n to generate a sequence of 64-bit, one-time passwords for remote\r\n user login. [R1760]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 306 of 436\n\nTutorial: The client generates a one-time password by applying the\r\n MD4 cryptographic hash function multiple times to the user's\r\n secret key. For each successive authentication of the user, the\r\n number of hash applications is reduced by one. (Thus, an intruder\r\n using wiretapping cannot compute a valid password from knowledge\r\n of one previously used.) The server verifies a password by hashing\r\n the currently presented password (or initialization value) one\r\n time and comparing the hash result with the previously presented\r\n password.\r\n $ S/MIME\r\n (I) See: Secure/MIME.\r\nShirey Informational [Page 257]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ SAD\r\n (I) See: Security Association Database.\r\n $ safety\r\n (I) The property of a system being free from risk of causing harm\r\n (especially physical harm) to its system entities. (Compare:\r\n security.)\r\n $ SAID\r\n (I) See: security association identifier.\r\n $ salami swindle\r\n (D) /slang/ \"Slicing off a small amount from each transaction.\r\n This kind of theft was made worthwhile by automation. Given a high\r\n transaction flow, even rounding down to the nearest cent and\r\n putting the 'extra' in a bogus account can be very profitable.\"\r\n [NCSSG]\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ salt\r\n (I) A data value used to vary the results of a computation in a\r\n security mechanism, so that an exposed computational result from\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 307 of 436\n\none instance of applying the mechanism cannot be reused by an\r\n attacker in another instance. (Compare: initialization value.)\r\n Example: A password-based access control mechanism might protect\r\n against capture or accidental disclosure of its password file by\r\n applying a one-way encryption algorithm to passwords before\r\n storing them in the file. To increase the difficulty of off-line,\r\n dictionary attacks that match encrypted values of potential\r\n passwords against a copy of the password file, the mechanism can\r\n concatenate each password with its own random salt value before\r\n applying the one-way function.\r\n $ SAML\r\n (N) See: Security Assertion Markup Language (SAML).\r\n $ sandbox\r\n (I) A restricted, controlled execution environment that prevents\r\n potentially malicious software, such as mobile code, from\r\n accessing any system resources except those for which the software\r\n is authorized.\r\nShirey Informational [Page 258]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ sanitize\r\n 1. (I) Delete sensitive data from a file, device, or system. (See:\r\n erase, zeroize.)\r\n 2. (I) Modify data so as to be able either (a) to completely\r\n declassify it or (b) to downgrade it to a lower security level.\r\n $ SAP\r\n (O) See: special access program.\r\n $ SASL\r\n (I) See: Simple Authentication and Security Layer.\r\n $ SCA\r\n (I) See: subordinate certification authority.\r\n $ scavenging\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 308 of 436\n\n(I) /threat action/ See: secondary definition under \"exposure\".\r\n $ SCI\r\n (O) See: sensitive compartmented information.\r\n $ SCIF\r\n (O) See: sensitive compartmented information facility.\r\n $ SCOMP\r\n (N) Secure COMmunications Processor; an enhanced, MLS version of\r\n the Honeywell Level 6 minicomputer. It was the first system to be\r\n rated in TCSEC Class A1. (See: KSOS.)\r\n $ screen room\r\n (D) /slang/ Synonym for \"shielded enclosure\" in the context of\r\n electromagnetic emanations. (See: EMSEC, TEMPEST.)\r\n Deprecated Term: To avoid international misunderstanding, IDOCs\r\n SHOULD NOT use this term.\r\n $ screening router\r\n (I) Synonym for \"filtering router\".\r\n $ script kiddy\r\n (D) /slang/ A cracker who is able to use existing attack\r\n techniques (i.e., to read scripts) and execute existing attack\r\n software, but is unable to invent new exploits or manufacture the\r\n tools to perform them; pejoratively, an immature or novice\r\n cracker.\r\nShirey Informational [Page 259]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ SDE\r\n (N) See: Secure Data Exchange.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 309 of 436\n\n$ SDNS\r\n (O) See: Secure Data Network System.\r\n $ SDU\r\n (N) See: \"service data unit\" under \"protocol data unit\".\r\n $ seal\r\n 1. (I) To use asymmetric cryptography to encrypt plain text with a\r\n public key in such a way that only the holder of the matching\r\n private key can learn what was the plain text. [Chau] (Compare:\r\n shroud, wrap.)\r\n Deprecated Usage: An IDOC SHOULD NOT use this term with definition\r\n 1 unless the IDOC includes the definition, because the definition\r\n is not widely known and the concept can be expressed by using\r\n other, standard terms. Instead, use \"salt and encrypt\" or other\r\n terminology that is specific with regard to the mechanism being\r\n used.\r\n Tutorial: The definition does *not* say \"only the holder of the\r\n matching private key can decrypt the ciphertext to learn what was\r\n the plaintext\"; sealing is stronger than that. If Alice simply\r\n encrypts a plaintext P with a public key K to produce ciphertext C\r\n = K(P), then if Bob guesses that P = X, Bob could verify the guess\r\n by checking whether K(P) = K(X). To \"seal\" P and block Bob's\r\n guessing attack, Alice could attach a long string R of random bits\r\n to P before encrypting to produce C = K(P,R); if Bob guesses that\r\n P = X, Bob can only test the guess by also guessing R. (See:\r\n salt.)\r\n 2. (D) To use cryptography to provide data integrity service for a\r\n data object. (See: sign.)\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 2. Instead, use a term that is more specific with\r\n regard to the mechanism used to provide the data integrity\r\n service; e.g., use \"sign\" when the mechanism is digital signature.\r\nShirey Informational [Page 260]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 310 of 436\n\n$ secret\r\n 1a. (I) /adjective/ The condition of information being protected\r\n from being known by any system entities except those that are\r\n intended to know it. (See: data confidentiality.)\r\n 1b. (I) /noun/ An item of information that is protected thusly.\r\n Usage: This term applies to symmetric keys, private keys, and\r\n passwords.\r\n $ secret key\r\n (D) A key that is kept secret or needs to be kept secret.\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it mixes concepts\r\n in a potentially misleading way. In the context of asymmetric\r\n cryptography, IDOCs SHOULD use \"private key\". In the context of\r\n symmetric cryptography, the adjective \"secret\" is unnecessary\r\n because all keys must be kept secret.\r\n $ secret-key cryptography\r\n (D) Synonym for \"symmetric cryptography\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it could be\r\n confused with \"asymmetric cryptography\", in which the private key\r\n is kept secret.\r\n Derivation: Symmetric cryptography is sometimes called \"secret-key\r\n cryptography\" because entities that share the key, such as the\r\n originator and the recipient of a message, need to keep the key\r\n secret from other entities.\r\n $ Secure BGP (S-BGP)\r\n (I) A project of BBN Technologies, sponsored by the U.S. DoD's\r\n Defense Advanced Research Projects Agency, to design and\r\n demonstrate an architecture to secure the Border Gateway Protocol\r\n (RFC 1771) and to promote deployment of that architecture in the\r\n Internet.\r\n Tutorial: S-BGP incorporates three security mechanisms:\r\n - A PKI supports authentication of ownership of IP address\r\n blocks, autonomous system (AS) numbers, an AS's identity, and a\r\n BGP router's identity and its authorization to represent an AS.\r\n This PKI parallels and takes advantage of the Internet's\r\n existing IP address and AS number assignment system.\r\n - A new, optional, BGP transitive path attribute carries digital\r\n signatures (in \"attestations\") covering the routing information\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 311 of 436\n\nin a BGP UPDATE. These signatures along with certificates from\r\n the S-BGP PKI enable the receiver of a BGP routing UPDATE to\r\nShirey Informational [Page 261]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n validate the attribute and gain trust in the address prefixes\r\n and path information that it contains.\r\n - IPsec provides data and partial sequence integrity, and enables\r\n BGP routers to authenticate each other for exchanges of BGP\r\n control traffic.\r\n $ Secure Data Exchange (SDE)\r\n (N) A LAN security protocol defined by the IEEE 802.10 standard.\r\n $ Secure Data Network System (SDNS)\r\n (O) An NSA program that developed security protocols for\r\n electronic mail (see: MSP), OSIRM Layer 3 (see: SP3), OSIRM Layer\r\n 4 (see: SP4), and key establishment (see: KMP).\r\n $ secure distribution\r\n (I) See: trusted distribution.\r\n $ Secure Hash Algorithm (SHA)\r\n (N) A cryptographic hash function (specified in SHS) that produces\r\n an output (see: \"hash result\") -- of selectable length of either\r\n 160, 224, 256, 384, or 512 bits -- for input data of any length \u003c\r\n 2**64 bits.\r\n $ Secure Hash Standard (SHS)\r\n (N) The U.S. Government standard [FP180] that specifies SHA.\r\n $ Secure Hypertext Transfer Protocol (S-HTTP)\r\n (I) An Internet protocol [R2660] for providing client-server\r\n security services for HTTP communications. (Compare: https.)\r\n Tutorial: S-HTTP was originally specified by CommerceNet, a\r\n coalition of businesses interested in developing the Internet for\r\n commercial uses. Several message formats may be incorporated into\r\n S-HTTP clients and servers, particularly CMS and MOSS. S-HTTP\r\n supports choice of security policies, key management mechanisms,\r\n and cryptographic algorithms through option negotiation between\r\n parties for each transaction. S-HTTP supports modes of operation\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 312 of 436\n\nfor both asymmetric and symmetric cryptography. S-HTTP attempts to\r\n avoid presuming a particular trust model, but it attempts to\r\n facilitate multiply rooted, hierarchical trust and anticipates\r\n that principals may have many public-key certificates.\r\n $ Secure/MIME (S/MIME)\r\n (I) Secure/Multipurpose Internet Mail Extensions, an Internet\r\n protocol [R3851] to provide encryption and digital signatures for\r\n Internet mail messages.\r\nShirey Informational [Page 262]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ secure multicast\r\n (I) Refers generally to providing security services for multicast\r\n groups of various types (e.g., 1-to-N and M-to-N) and to classes\r\n of protocols used to protect multicast packets.\r\n Tutorial: Multicast applications include video broadcast and\r\n multicast file transfer, and many of these applications require\r\n network security services. The Multicast Security Reference\r\n Framework [R3740] covers three functional areas:\r\n - Multicast data handling: Security-related treatment of\r\n multicast data by the sender and the receiver.\r\n - Group key management: Secure distribution and refreshment of\r\n keying material. (See: Group Domain of Interpretation.)\r\n - Multicast security policy: Policy translation and\r\n interpretation across the multiple administrative domains that\r\n typically are spanned by a multicast application.\r\n $ Secure Shell(trademark) (SSH(trademark))\r\n (N) Refers to a protocol for secure remote login and other secure\r\n network services.\r\n Usage: On the Web site of SSH Communication Security Corporation,\r\n at http://www.ssh.com/legal_notice.html, it says, \"SSH [and] the\r\n SSH logo ... are either trademarks or registered trademarks of\r\n SSH.\" This Glossary seeks to make readers aware of this trademark\r\n claim but takes no position on its validity.\r\n Tutorial: SSH has three main parts:\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 313 of 436\n\n- Transport layer protocol: Provides server authentication,\r\n confidentiality, and integrity; and can optionally provide\r\n compression. This layer typically runs over a TCP connection,\r\n but might also run on top of any other reliable data stream.\r\n - User authentication protocol: Authenticates the client-side\r\n user to the server. It runs over the transport layer protocol.\r\n - Connection protocol: Multiplexes the encrypted tunnel into\r\n several logical channels. It runs over the user authentication\r\n protocol.\r\n $ Secure Sockets Layer (SSL)\r\n (N) An Internet protocol (originally developed by Netscape\r\n Communications, Inc.) that uses connection-oriented end-to-end\r\n encryption to provide data confidentiality service and data\r\n integrity service for traffic between a client (often a web\r\n browser) and a server, and that can optionally provide peer entity\r\n authentication between the client and the server. (See: Transport\r\n Layer Security.)\r\nShirey Informational [Page 263]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: SSL has two layers; SSL's lower layer, the SSL Record\r\n Protocol, is layered on top of an IPS Transport-Layer protocol and\r\n encapsulates protocols that run in the upper layer. The upper-\r\n layer protocols are the three SSL management protocols -- SSL\r\n Handshake Protocol, SSL Change Cipher Spec Protocol, or SSL Alert\r\n Protocol -- and some Application-Layer protocol (e.g., HTTP).\r\n The SSL management protocols provide asymmetric cryptography for\r\n server authentication (verifying the server's identity to the\r\n client) and optional client authentication (verifying the client's\r\n identity to the server), and also enable them, before the\r\n application protocol transmits or receives data, to negotiate a\r\n symmetric encryption algorithm and secret session key (to use for\r\n data confidentiality service) and a keyed hash (to use for data\r\n integrity service).\r\n SSL is independent of the application it encapsulates, and any\r\n application can layer on top of SSL transparently. However, many\r\n Internet applications might be better served by IPsec.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 314 of 436\n\n$ secure state\r\n 1a. (I) A system condition in which the system is in conformance\r\n with the applicable security policy. (Compare: clean system,\r\n transaction.)\r\n 1b. (I) /formal model/ A system condition in which no subject can\r\n access any object in an unauthorized manner. (See: secondary\r\n definition under \"Bell-LaPadula model\".)\r\n $ security\r\n 1a. (I) A system condition that results from the establishment and\r\n maintenance of measures to protect the system.\r\n 1b. (I) A system condition in which system resources are free from\r\n unauthorized access and from unauthorized or accidental change,\r\n destruction, or loss. (Compare: safety.)\r\n 2. (I) Measures taken to protect a system.\r\n Tutorial: Parker [Park] suggests that providing a condition of\r\n system security may involve the following six basic functions,\r\n which overlap to some extent:\r\n - \"Deterrence\": Reducing an intelligent threat by discouraging\r\n action, such as by fear or doubt. (See: attack, threat action.)\r\n - \"Avoidance\": Reducing a risk by either reducing the value of\r\n the potential loss or reducing the probability that the loss\r\n will occur. (See: risk analysis. Compare: \"risk avoidance\"\r\n under \"risk\".)\r\nShirey Informational [Page 264]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - \"Prevention\": Impeding or thwarting a potential security\r\n violation by deploying a countermeasure.\r\n - \"Detection\": Determining that a security violation is\r\n impending, is in progress, or has recently occurred, and thus\r\n make it possible to reduce the potential loss. (See: intrusion\r\n detection.)\r\n - \"Recovery\": Restoring a normal state of system operation by\r\n compensating for a security violation, possibly by eliminating\r\n or repairing its effects. (See: contingency plan, main entry\r\n for \"recovery\".)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 315 of 436\n\n- \"Correction\": Changing a security architecture to eliminate or\r\n reduce the risk of reoccurrence of a security violation or\r\n threat consequence, such as by eliminating a vulnerability.\r\n $ security architecture\r\n (I) A plan and set of principles that describe (a) the security\r\n services that a system is required to provide to meet the needs of\r\n its users, (b) the system components required to implement the\r\n services, and (c) the performance levels required in the\r\n components to deal with the threat environment (e.g., [R2179]).\r\n (See: defense in depth, IATF, OSIRM Security Architecture,\r\n security controls, Tutorial under \"security policy\".)\r\n Tutorial: A security architecture is the result of applying the\r\n system engineering process. A complete system security\r\n architecture includes administrative security, communication\r\n security, computer security, emanations security, personnel\r\n security, and physical security. A complete security architecture\r\n needs to deal with both intentional, intelligent threats and\r\n accidental threats.\r\n $ Security Assertion Markup Language (SAML)\r\n (N) A protocol consisting of XML-based request and response\r\n message formats for exchanging security information, expressed in\r\n the form of assertions about subjects, between on-line business\r\n partners. [SAML]\r\n $ security association\r\n 1. (I) A relationship established between two or more entities to\r\n enable them to protect data they exchange. (See: association,\r\n ISAKMP, SAD. Compare: session.)\r\n Tutorial: The relationship is represented by a set of data that is\r\n shared between the entities and is agreed upon and considered a\r\n contract between them. The data describes how the associated\r\n entities jointly use security services. The relationship is used\r\n to negotiate characteristics of security mechanisms, but the\r\nShirey Informational [Page 265]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n relationship is usually understood to exclude the mechanisms\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 316 of 436\n\nthemselves.\r\n 2. (I) /IPsec/ A simplex (uni-directional) logical connection\r\n created for security purposes and implemented with either AH or\r\n ESP (but not both). The security services offered by a security\r\n association depend on the protocol (AH or ESP), the IPsec mode\r\n (transport or tunnel), the endpoints, and the election of optional\r\n services within the protocol. A security association is identified\r\n by a triple consisting of (a) a destination IP address, (b) a\r\n protocol (AH or ESP) identifier, and (c) a Security Parameter\r\n Index.\r\n 3. (O) \"A set of policy and cryptographic keys that provide\r\n security services to network traffic that matches that policy\".\r\n [R3740] (See: cryptographic association, group security\r\n association.)\r\n 4. (O) \"The totality of communications and security mechanisms and\r\n functions (e.g., communications protocols, security protocols,\r\n security mechanisms and functions) that securely binds together\r\n two security contexts in different end systems or relay systems\r\n supporting the same information domain.\" [DoD6]\r\n $ Security Association Database (SAD)\r\n (I) /IPsec/ In an IPsec implementation that operates in a network\r\n node, a database that contains parameters to describe the status\r\n and operation of each of the active security associations that the\r\n node has established with other nodes. Separate inbound and\r\n outbound SADs are needed because of the directionality of IPsec\r\n security associations. [R4301] (Compare: SPD.)\r\n $ security association identifier (SAID)\r\n (I) A data field in a security protocol (such as NLSP or SDE),\r\n used to identify the security association to which a PDU is bound.\r\n The SAID value is usually used to select a key for decryption or\r\n authentication at the destination. (See: Security Parameter\r\n Index.)\r\n $ security assurance\r\n 1. (I) An attribute of an information system that provides grounds\r\n for having confidence that the system operates such that the\r\n system's security policy is enforced. (Compare: trust.)\r\n 2. (I) A procedure that ensures a system is developed and operated\r\n as intended by the system's security policy.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 317 of 436\n\nShirey Informational [Page 266]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 3. (D) \"The degree of confidence one has that the security\r\n controls operate correctly and protect the system as intended.\"\r\n [SP12]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 3; it is a\r\n definition for \"assurance level\" rather than for \"assurance\".\r\n 4. (D) /U.S. Government, identity authentication/ The (a) \"degree\r\n of confidence in the vetting process used to establish the\r\n identity of the individual to whom the [identity] credential was\r\n issued\" and the (b) \"degree of confidence that the individual who\r\n uses the credential is the individual to whom the credential was\r\n issued\". [M0404]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 4; it mixes\r\n concepts in a potentially misleading way. Part \"a\" is a definition\r\n for \"assurance level\" (rather than \"security assurance\") of an\r\n identity registration process; and part \"b\" is a definition for\r\n \"assurance level\" (rather than \"security assurance\") of an\r\n identity authentication process. Also, the processes of\r\n registration and authentication should be defined and designed\r\n separately to ensure clarity in certification.\r\n $ security audit\r\n (I) An independent review and examination of a system's records\r\n and activities to determine the adequacy of system controls,\r\n ensure compliance with established security policy and procedures,\r\n detect breaches in security services, and recommend any changes\r\n that are indicated for countermeasures. [I7498-2, NCS01] (Compare:\r\n accounting, intrusion detection.)\r\n Tutorial: The basic audit objective is to establish accountability\r\n for system entities that initiate or participate in security-\r\n relevant events and actions. Thus, means are needed to generate\r\n and record a security audit trail and to review and analyze the\r\n audit trail to discover and investigate security violations.\r\n $ security audit trail\r\n (I) A chronological record of system activities that is sufficient\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 318 of 436\n\nto enable the reconstruction and examination of the sequence of\r\n environments and activities surrounding or leading to an\r\n operation, procedure, or event in a security-relevant transaction\r\n from inception to final results. [NCS04] (See: security audit.)\r\n $ security by obscurity\r\n (O) Attempting to maintain or increase security of a system by\r\n keeping secret the design or construction of a security mechanism.\r\nShirey Informational [Page 267]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: This approach has long been discredited in cryptography,\r\n where the phrase refers to trying to keep an algorithm secret,\r\n rather than just concealing the keys [Schn]. One must assume that\r\n mass-produced or widely fielded cryptographic devices eventually\r\n will be lost or stolen and, therefore, that the algorithms will be\r\n reverse engineered and become known to the adversary. Thus, one\r\n should rely on only those algorithms and protocols that are strong\r\n enough to have been published widely, and have been peer reviewed\r\n for long enough that their flaws have been found and removed. For\r\n example, NIST used a long, public process to select AES to replace\r\n DES.\r\n In computer and network security, the principle of \"no security by\r\n obscurity\" also applies to security mechanisms other than\r\n cryptography. For example, if the design and implementation of a\r\n protocol for access control are strong, then reading the\r\n protocol's source code should not enable you to find a way to\r\n evade the protection and penetrate the system.\r\n $ security class\r\n (D) Synonym for \"security level\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term. Instead, use\r\n \"security level\", which is more widely established and understood.\r\n $ security clearance\r\n (I) A determination that a person is eligible, under the standards\r\n of a specific security policy, for authorization to access\r\n sensitive information or other system resources. (See: clearance\r\n level.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 319 of 436\n\n$ security compromise\r\n (I) A security violation in which a system resource is exposed, or\r\n is potentially exposed, to unauthorized access. (Compare: data\r\n compromise, exposure, violation.)\r\n $ security controls\r\n (N) The management, operational, and technical controls\r\n (safeguards or countermeasures) prescribed for an information\r\n system which, taken together, satisfy the specified security\r\n requirements and adequately protect the confidentiality,\r\n integrity, and availability of the system and its information.\r\n [FP199] (See: security architecture.)\r\n $ security doctrine\r\n (I) A specified set of procedures or practices that direct or\r\n provide guidance for how to comply with security policy. (Compare:\r\n security mechanism, security policy.)\r\nShirey Informational [Page 268]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: Security policy and security doctrine are closely\r\n related. However, policy deals mainly with strategy, and doctrine\r\n deals with tactics.\r\n Security doctrine is often understood to refer mainly to\r\n administrative security, personnel security, and physical\r\n security. For example, security mechanisms and devices that\r\n implement them are normally designed to operate in a limited range\r\n of environmental and administrative conditions, and these\r\n conditions must be met to complement and ensure the technical\r\n protection afforded by the hardware, firmware, and software in the\r\n devices. Security doctrine specifies how to achieve those\r\n conditions. (See: \"first law\" under \"Courtney's laws\".)\r\n $ security domain\r\n (I) See: domain.\r\n $ security environment\r\n (I) The set of external entities, procedures, and conditions that\r\n affect secure development, operation, and maintenance of a system.\r\n (See: \"first law\" under \"Courtney's laws\".)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 320 of 436\n\n$ security event\r\n (I) An occurrence in a system that is relevant to the security of\r\n the system. (See: security incident.)\r\n Tutorial: The term covers both events that are security incidents\r\n and those that are not. In a CA workstation, for example, a list\r\n of security events might include the following:\r\n - Logging an operator into or out of the system.\r\n - Performing a cryptographic operation, e.g., signing a digital\r\n certificate or CRL.\r\n - Performing a cryptographic card operation: creation, insertion,\r\n removal, or backup.\r\n - Performing a digital certificate lifecycle operation: rekey,\r\n renewal, revocation, or update.\r\n - Posting a digital certificate to an X.500 Directory.\r\n - Receiving a key compromise notification.\r\n - Receiving an improper certification request.\r\n - Detecting an alarm condition reported by a cryptographic\r\n module.\r\n - Failing a built-in hardware self-test or a software system\r\n integrity check.\r\n $ security fault analysis\r\n (I) A security analysis, usually performed on hardware at the\r\n level of gate logic, gate-by-gate, to determine the security\r\n properties of a device when a hardware fault is encountered.\r\nShirey Informational [Page 269]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ security function\r\n (I) A function in a system that is relevant to the security of the\r\n system; i.e., a system function that must operate correctly to\r\n ensure adherence to the system's security policy.\r\n $ security gateway\r\n 1. (I) An internetwork gateway that separates trusted (or\r\n relatively more trusted) hosts on one side from untrusted (or less\r\n trusted) hosts on the other side. (See: firewall and guard.)\r\n 2. (O) /IPsec/ \"An intermediate system that implements IPsec\r\n protocols.\" [R4301]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 321 of 436\n\nTutorial: IPsec's AH or ESP can be implemented on a gateway\r\n between a protected network and an unprotected network, to provide\r\n security services to the protected network's hosts when they\r\n communicate across the unprotected network to other hosts and\r\n gateways.\r\n $ security incident\r\n 1. (I) A security event that involves a security violation. (See:\r\n CERT, security event, security intrusion, security violation.)\r\n Tutorial: In other words, a security event in which the system's\r\n security policy is disobeyed or otherwise breached.\r\n 2. (D) \"Any adverse event [that] compromises some aspect of\r\n computer or network security.\" [R2350]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 2 because\r\n (a) a security incident may occur without actually being harmful\r\n (i.e., adverse) and because (b) this Glossary defines \"compromise\"\r\n more narrowly in relation to unauthorized access.\r\n 3. (D) \"A violation or imminent threat of violation of computer\r\n security policies, acceptable use policies, or standard computer\r\n security practices.\" [SP61]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 3 because\r\n it mixes concepts in way that does not agree with common usage; a\r\n security incident is commonly thought of as involving a\r\n realization of a threat (see: threat action), not just a threat.\r\n $ security intrusion\r\n (I) A security event, or a combination of multiple security\r\n events, that constitutes a security incident in which an intruder\r\n gains, or attempts to gain, access to a system or system resource\r\n without having authorization to do so.\r\nShirey Informational [Page 270]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ security kernel\r\n (I) \"The hardware, firmware, and software elements of a trusted\r\n computing base that implement the reference monitor concept. It\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 322 of 436\n\nmust mediate all accesses, be protected from modification, and be\r\n verifiable as correct.\" [NCS04] (See: kernel, TCB.)\r\n Tutorial: A security kernel is an implementation of a reference\r\n monitor for a given hardware base. [Huff]\r\n $ security label\r\n (I) An item of meta-data that designates the value of one or more\r\n security-relevant attributes (e.g., security level) of a system\r\n resource. (See: [R1457]. Compare: security marking.)\r\n Deprecated usage: To avoid confusion, IDOCs SHOULD NOT use\r\n \"security label\" for \"security marking\", or vice versa, even\r\n though that is commonly done (including in some national and\r\n international standards that should know better).\r\n Tutorial: Humans and automated security mechanisms use a security\r\n label of a system resource to determine, according to applicable\r\n security policy, how to control access to the resource (and they\r\n affix appropriate, matching security markings to physical\r\n instances of the resource). Security labels are most often used to\r\n support data confidentiality policy, and sometimes used to support\r\n data integrity policy.\r\n As explained in [R1457], the form that is taken by security labels\r\n of a protocol's packets varies depending on the OSIRM layer in\r\n which the protocol operates. Like meta-data generally, a security\r\n label of a data packet may be either explicit (e.g., IPSO) or\r\n implicit (e.g., Alice treats all messages received from Bob as\r\n being labeled \"Not For Public Release\"). In a connectionless\r\n protocol, every packet might have an explicit label; but in a\r\n connection-oriented protocol, all packets might have the same\r\n implicit label that is determined at the time the connection is\r\n established.\r\n Both classified and unclassified system resources may require a\r\n security label. (See: FOUO.)\r\n $ security level\r\n (I) The combination of a hierarchical classification level and a\r\n set of non-hierarchical category designations that represents how\r\n sensitive a specified type or item of information is. (See:\r\n dominate, lattice model. Compare: classification level.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 323 of 436\n\nShirey Informational [Page 271]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: IDOCs that use this term SHOULD state a definition for it.\r\n The term is usually understood to involve sensitivity to\r\n disclosure, but it also is used in many other ways and could\r\n easily be misunderstood.\r\n $ Security Level field\r\n (I) A 16-bit field that specifies a security level value in the\r\n security option (option type 130) of version 4 IP's datagram\r\n header format.\r\n Deprecated Abbreviation: IDOCs SHOULD NOT use the abbreviation \"S\r\n field\", which is potentially ambiguous.\r\n $ security management infrastructure (SMI)\r\n (I) System components and activities that support security policy\r\n by monitoring and controlling security services and mechanisms,\r\n distributing security information, and reporting security events.\r\n Tutorial: The associated functions are as follows [I7498-4]:\r\n - Controlling (granting or restricting) access to system\r\n resources: This includes verifying authorizations and\r\n identities, controlling access to sensitive security data, and\r\n modifying access priorities and procedures in the event of\r\n attacks.\r\n - Retrieving (gathering) and archiving (storing) security\r\n information: This includes logging security events and\r\n analyzing the log, monitoring and profiling usage, and\r\n reporting security violations.\r\n - Managing and controlling the encryption process: This includes\r\n performing the functions of key management and reporting on key\r\n management problems. (See: PKI.)\r\n $ security marking\r\n (I) A physical marking that is bound to an instance of a system\r\n resource and that represents a security label of the resource,\r\n i.e., that names or designates the value of one or more security-\r\n relevant attributes of the resource. (Compare: security label.)\r\n Tutorial: A security label may be represented by various\r\n equivalent markings depending on the physical form taken by the\r\n labeled resource. For example, a document could have a marking\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 324 of 436\n\ncomposed of a bit pattern [FP188] when the document is stored\r\n electronically as a file in a computer, and also a marking of\r\n printed alphabetic characters when the document is in paper form.\r\nShirey Informational [Page 272]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ security mechanism\r\n (I) A method or process (or a device incorporating it) that can be\r\n used in a system to implement a security service that is provided\r\n by or within the system. (See: Tutorial under \"security policy\".\r\n Compare: security doctrine.)\r\n Usage: Usually understood to refer primarily to components of\r\n communication security, computer security, and emanation security.\r\n Examples: Authentication exchange, checksum, digital signature,\r\n encryption, and traffic padding.\r\n $ security model\r\n (I) A schematic description of a set of entities and relationships\r\n by which a specified set of security services are provided by or\r\n within a system. Example: Bell-LaPadula model, OSIRM. (See:\r\n Tutorial under \"security policy\".)\r\n $ security parameters index (SPI)\r\n 1. (I) /IPsec/ A 32-bit identifier used to distinguish among\r\n security associations that terminate at the same destination (IP\r\n address) and use the same security protocol (AH or ESP). Carried\r\n in AH and ESP to enable the receiving system to determine under\r\n which security association to process a received packet.\r\n 2. (I) /mobile IP/ A 32-bit index identifying a security\r\n association from among the collection of associations that are\r\n available between a pair of nodes, for application to mobile IP\r\n protocol messages that the nodes exchange.\r\n $ security perimeter\r\n (I) A physical or logical boundary that is defined for a domain or\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 325 of 436\n\nenclave and within which a particular security policy or security\r\n architecture applies. (See: insider, outsider.)\r\n $ security policy\r\n 1. (I) A definite goal, course, or method of action to guide and\r\n determine present and future decisions concerning security in a\r\n system. [NCS03, R3198] (Compare: certificate policy.)\r\n 2a. (I) A set of policy rules (or principles) that direct how a\r\n system (or an organization) provides security services to protect\r\n sensitive and critical system resources. (See: identity-based\r\n security policy, policy rule, rule-based security policy, rules of\r\n behavior. Compare: security architecture, security doctrine,\r\n security mechanism, security model, [R1281].)\r\nShirey Informational [Page 273]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2b. (O) A set of rules to administer, manage, and control access\r\n to network resources. [R3060, R3198]\r\n 2c. (O) /X.509/ A set of rules laid down by an authority to govern\r\n the use and provision of security services and facilities.\r\n 2d. (O) /Common Criteria/ A set of rules that regulate how assets\r\n are managed, protected, and distributed within a TOE.\r\n Tutorial: Ravi Sandhu suggests that security policy is one of four\r\n layers of the security engineering process (as shown in the\r\n following diagram). Each layer provides a different view of\r\n security, ranging from what services are needed to how services\r\n are implemented.\r\n What Security Services\r\n Should Be Provided? +- - - - - - - - - - - - -+\r\n ^ +- - - - - - - - - - - -| Mission Functions View |\r\n | | Security Policy |- - - - - - - - - - - - -+\r\n | +- - - - - - - - - - - -| Domain Practices View |\r\n | | Security Model |- - - - - - - - - - - - -+\r\n | +- - - - - - - - - - - -| Enclave Services View |\r\n | | Security Architecture |- - - - - - - - - - - - -+\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 326 of 436\n\n| +- - - - - - - - - - - -| Agent Mechanisms View |\r\n | | Security Mechanism |- - - - - - - - - - - - -+\r\n v +- - - - - - - - - - - -| Platform Devices View |\r\n How Are Security +- - - - - - - - - - - - -+\r\n Services Implemented?\r\n We suggest that each of Sandhu's four layers is a mapping between\r\n two points of view that differ in their degree of abstraction,\r\n according to the perspectives of various participants in system\r\n design, development, and operation activities, as follows:.\r\n - Mission functions view: The perspective of a user of system\r\n resources. States time-phased protection needs for resources\r\n and identifies sensitive and critical resources -- networks,\r\n hosts, applications, and databases. Independent of rules and\r\n practices used to achieve protection.\r\n - Domain practices view: The perspective of an enterprise manager\r\n who sets protection standards for resources. States rules and\r\n practices for protection. Identifies domain members; i.e.,\r\n entities (users/providers) and resources (including data\r\n objects). Independent of system topology. Not required to be\r\n hierarchical.\r\n - Enclave services view: The perspective of a system designer who\r\n allocates security functions to major components. Assigns\r\n security services to system topology structures and their\r\nShirey Informational [Page 274]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n contents. Independent of security mechanisms. Hierarchical\r\n across all domains.\r\n - Agent mechanisms view: The perspective of a system engineer who\r\n specifies security mechanisms to implement security services.\r\n Specifies mechanisms to be used by protocol, database, and\r\n application engines. Independent of type and manufacture of\r\n platforms and other physical devices.\r\n - Platform devices view: The perspective of an as-built\r\n description of the system in operation. Specifies exactly how\r\n to build or assemble the system, and also specifies procedures\r\n for operating the system.\r\n $ Security Policy Database (SPD)\r\n (I) /IPsec/ In an IPsec implementation operating in a network\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 327 of 436\n\nnode, a database that contains parameters that specify policies\r\n set by a user or administrator to determine what IPsec services,\r\n if any, are to be provided to IP datagrams sent or received by the\r\n node, and in what fashion they are provided. For each datagram,\r\n the SPD specifies one of three choices: discard the datagram,\r\n apply IPsec services (e.g., AH or ESP), or bypass IPsec. Separate\r\n inbound and outbound SPDs are needed because of the directionality\r\n of IPsec security associations. [R4301] (Compare: SAD.)\r\n $ Security Protocol 3 (SP3)\r\n (O) A protocol [SDNS3] developed by SDNS to provide connectionless\r\n data security at the top of OSIRM Layer 3. (Compare: IPsec, NLSP.)\r\n $ Security Protocol 4 (SP4)\r\n (O) A protocol [SDNS4] developed by SDNS to provide either\r\n connectionless or end-to-end connection-oriented data security at\r\n the bottom of OSIRM Layer 4. (See: TLSP.)\r\n $ security-relevant event\r\n (D) Synonym for \"security event\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is wordy.\r\n $ security-sensitive function\r\n (D) Synonym for \"security function\".\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is wordy.\r\n $ security service\r\n 1. (I) A processing or communication service that is provided by a\r\n system to give a specific kind of protection to system resources.\r\n (See: access control service, audit service, availability service,\r\n data confidentiality service, data integrity service, data origin\r\nShirey Informational [Page 275]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n authentication service, non-repudiation service, peer entity\r\n authentication service, system integrity service.)\r\n Tutorial: Security services implement security policies, and are\r\n implemented by security mechanisms.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 328 of 436\n\n2. (O) \"A service, provided by a layer of communicating open\r\n systems, [that] ensures adequate security of the systems or the\r\n data transfers.\" [I7498-2]\r\n $ security situation\r\n (I) /ISAKMP/ The set of all security-relevant information (e.g.,\r\n network addresses, security classifications, manner of operation\r\n such as normal or emergency) that is needed to decide the security\r\n services that are required to protect the association that is\r\n being negotiated.\r\n $ security target\r\n (N) /Common Criteria/ A set of security requirements and\r\n specifications to be used as the basis for evaluation of an\r\n identified TOE.\r\n Tutorial: A security target (ST) is a statement of security claims\r\n for a particular information technology security product or\r\n system, and is the basis for agreement among all parties as to\r\n what security the product or system offers. An ST parallels the\r\n structure of a protection profile, but has additional elements\r\n that include product-specific detailed information. An ST contains\r\n a summary specification, which defines the specific measures taken\r\n in the product or system to meet the security requirements.\r\n $ security token\r\n (I) See: token.\r\n $ security violation\r\n (I) An act or event that disobeys or otherwise breaches security\r\n policy. (See: compromise, penetration, security incident.)\r\n $ seed\r\n (I) A value that is an input to a pseudorandom number generator.\r\n $ selective-field confidentiality\r\n (I) A data confidentiality service that preserves confidentiality\r\n for one or more parts (i.e., fields) of each packet. (See:\r\n selective-field integrity.)\r\n Tutorial: Data confidentiality service usually is applied to\r\n entire SDUs, but some situations might require protection of only\r\nShirey Informational [Page 276]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 329 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n part of each packet. For example, when Alice uses a debit card at\r\n an automated teller machine (ATM), perhaps only her PIN is\r\n enciphered for confidentiality when her transaction request is\r\n transmitted from the ATM to her bank's computer.\r\n In any given operational situation, there could be many different\r\n reasons for using selective field confidentiality. In the ATM\r\n example, there are at least four possibilities: The service may\r\n provide a fail-safe mode of operation, ensuring that the bank can\r\n still process transactions (although with some risk) even when the\r\n encryption system fails. It may make messages easier to work with\r\n when doing system fault isolation. It may avoid problems with laws\r\n that prevent shipping enciphered data across international\r\n borders. It may improve efficiency by reducing processing load at\r\n a central computer site.\r\n $ selective-field integrity\r\n (I) A data integrity service that preserves integrity for one or\r\n more parts (i.e., fields) of each packet. (See: selective-field\r\n confidentiality.)\r\n Tutorial: Data integrity service may be implemented in a protocol\r\n to protect the SDU part of packets, the PCI part, or both.\r\n - SDU protection: When service is provided for SDUs, it usually\r\n is applied to entire SDUs, but it might be applied only to\r\n parts of SDUs in some situations. For example, an IPS\r\n Application-Layer protocol might need protection of only part\r\n of each packet, and this might enable faster processing.\r\n - PCI protection: To prevent active wiretapping, it might be\r\n desirable to apply data integrity service to the entire PCI,\r\n but some PCI fields in some protocols need to be mutable in\r\n transit. For example, the \"Time to Live\" field in IPv4 is\r\n changed each time a packet passes through a router in the\r\n Internet Layer. Thus, the value that the field will have when\r\n the packet arrives at its destination is not predictable by the\r\n sender and cannot be included in a checksum computed by the\r\n sender. (See: Authentication Header.)\r\n $ self-signed certificate\r\n (I) A public-key certificate for which the public key bound by the\r\n certificate and the private key used to sign the certificate are\r\n components of the same key pair, which belongs to the signer.\r\n (Compare: root certificate.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 330 of 436\n\nTutorial: In a self-signed X.509 public-key certificate, the\r\n issuer's DN is the same as the subject's DN.\r\nShirey Informational [Page 277]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ semantic security\r\n (I) An attribute of an encryption algorithm that is a\r\n formalization of the notion that the algorithm not only hides the\r\n plain text but also reveals no partial information about the plain\r\n text; i.e., whatever is computable about the plain text when given\r\n the cipher text, is also computable without the cipher text.\r\n (Compare: indistinguishability.)\r\n $ semiformal\r\n (I) Expressed in a restricted syntax language with defined\r\n semantics. [CCIB] (Compare: formal, informal.)\r\n $ sensitive\r\n (I) A condition of a system resource such that the loss of some\r\n specified property of that resource, such as confidentiality or\r\n integrity, would adversely affect the interests or business of its\r\n owner or user. (See: sensitive information. Compare: critical.)\r\n $ sensitive compartmented information (SCI)\r\n (O) /U.S. Government/ Classified information concerning or derived\r\n from intelligence sources, methods, or analytical processes, which\r\n is required to be handled within formal control systems\r\n established by the Director of Central Intelligence. [C4009] (See:\r\n compartment, SAP, SCIF. Compare: collateral information.)\r\n $ sensitive compartmented information facility (SCIF)\r\n (O) /U.S. Government/ \"An accredited area, room, group of rooms,\r\n building, or installation where SCI may be stored, used,\r\n discussed, and/or processed.\" [C4009] (See: SCI. Compare: shielded\r\n enclosure.)\r\n $ sensitive information\r\n 1. (I) Information for which (a) disclosure, (b) alteration, or\r\n (c) destruction or loss could adversely affect the interests or\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 331 of 436\n\nbusiness of its owner or user. (See: data confidentiality, data\r\n integrity, sensitive. Compare: classified, critical.)\r\n 2. (O) /U.S. Government/ Information for which (a) loss, (b)\r\n misuse, (c) unauthorized access, or (d) unauthorized modification\r\n could adversely affect the national interest or the conduct of\r\n federal programs, or the privacy to which individuals are entitled\r\n under the Privacy Act of 1974, but that has not been specifically\r\n authorized under criteria established by an Executive Order or an\r\n Act of Congress to be kept classified in the interest of national\r\n defense or foreign policy.\r\n Tutorial: Systems that are not U.S. national security systems, but\r\n contain sensitive U.S. Federal Government information, must be\r\nShirey Informational [Page 278]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n protected according to the Computer Security Act of 1987 (Public\r\n Law 100-235). (See: national security.)\r\n $ sensitivity label\r\n (D) Synonym for \"classification label\".\r\n Deprecated term: IDOCs SHOULD NOT use this term because the\r\n definition of \"sensitive\" involves not only data confidentiality,\r\n but also data integrity.\r\n $ sensitivity level\r\n (D) Synonym for \"classification level\".\r\n Deprecated term: IDOCs SHOULD NOT use this term because the\r\n definition of \"sensitive\" involves not only data confidentiality,\r\n but also data integrity.\r\n $ separation of duties\r\n (I) The practice of dividing the steps in a system process among\r\n different individual entities (i.e., different users or different\r\n roles) so as to prevent a single entity acting alone from being\r\n able to subvert the process. Usage: a.k.a. \"separation of\r\n privilege\". (See: administrative security, dual control.)\r\n $ serial number\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 332 of 436\n\nSee: certificate serial number.\r\n $ Serpent\r\n (O) A symmetric, 128-bit block cipher designed by Ross Anderson,\r\n Eli Biham, and Lars Knudsen as a candidate for the AES.\r\n $ server\r\n (I) A system entity that provides a service in response to\r\n requests from other system entities called clients.\r\n $ service data unit (SDU)\r\n (N) See: secondary definition under \"protocol data unit\".\r\n $ session\r\n 1a. (I) /computer usage/ A continuous period of time, usually\r\n initiated by a login, during which a user accesses a computer\r\n system.\r\n 1b. (I) /computer activity/ The set of transactions or other\r\n computer activities that are performed by or for a user during a\r\n period of computer usage.\r\nShirey Informational [Page 279]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 2. (I) /access control/ A temporary mapping of a principal to one\r\n or more roles. (See: role-based access control.)\r\n Tutorial: A user establishes a session as a principal and\r\n activates some subset of roles to which the principal has been\r\n assigned. The authorizations available to the principal in the\r\n session are the union of the permissions of all the roles\r\n activated in the session. Each session is associated with a single\r\n principal and, therefore, with a single user. A principal may have\r\n multiple, concurrent sessions and may activate a different set of\r\n roles in each session.\r\n 3. (I) /computer network/ A persistent but (normally) temporary\r\n association between a user agent (typically a client) and a second\r\n process (typically a server). The association may persist across\r\n multiple exchanges of data, including multiple connections.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 333 of 436\n\n(Compare: security association.)\r\n $ session key\r\n (I) In the context of symmetric encryption, a key that is\r\n temporary or is used for a relatively short period of time. (See:\r\n ephemeral, KDC, session. Compare: master key.)\r\n Tutorial: A session key is used for a defined period of\r\n communication between two system entities or components, such as\r\n for the duration of a single connection or transaction set; or the\r\n key is used in an application that protects relatively large\r\n amounts of data and, therefore, needs to be rekeyed frequently.\r\n $ SET(trademark)\r\n (O) See: SET Secure Electronic Transaction(trademark).\r\n $ SET private extension\r\n (O) One of the private extensions defined by SET for X.509\r\n certificates. Carries information about hashed root key,\r\n certificate type, merchant data, cardholder certificate\r\n requirements, encryption support for tunneling, or message support\r\n for payment instructions.\r\n $ SET qualifier\r\n (O) A certificate policy qualifier that provides information about\r\n the location and content of a SET certificate policy.\r\n Tutorial: Besides the policies and qualifiers inherited from its\r\n own certificate, each CA in the SET certification hierarchy may\r\n add one qualifying statement to the root policy when the CA issues\r\n a certificate. The additional qualifier is a certificate policy\r\n for that CA. Each policy in a SET certificate may have these\r\nShirey Informational [Page 280]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n qualifiers: (a) a URL where a copy of the policy statement may be\r\n found; (b) an electronic mail address where a copy of the policy\r\n statement may be found; (c) a hash result of the policy statement,\r\n computed using the indicated algorithm; and (d) a statement\r\n declaring any disclaimers associated with the issuing of the\r\n certificate.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 334 of 436\n\n$ SET Secure Electronic Transaction(trademark) or SET(trademark)\r\n (N) A protocol developed jointly by MasterCard International and\r\n Visa International and published as an open standard to provide\r\n confidentiality of transaction information, payment integrity, and\r\n authentication of transaction participants for payment card\r\n transactions over unsecured networks, such as the Internet. [SET1]\r\n (See: acquirer, brand, cardholder, dual signature, electronic\r\n commerce, IOTP, issuer, merchant, payment gateway, third party.)\r\n Tutorial: This term and acronym are trademarks of SETCo.\r\n MasterCard and Visa announced the SET standard on 1 February 1996.\r\n $ SETCo\r\n (O) Abbreviation of \"SET Secure Electronic Transaction LLC\",\r\n formed on 19 December 1997 by MasterCard and Visa for implementing\r\n the SET Secure Electronic Transaction(trademark) standard. A later\r\n memorandum of understanding added American Express and JCB Credit\r\n Card Company as co-owners of SETCo.\r\n $ SHA, SHA-1, SHA-2\r\n (N) See: Secure Hash Algorithm.\r\n $ shared identity\r\n (I) See: secondary definition under \"identity\".\r\n $ shared secret\r\n (D) Synonym for \"cryptographic key\" or \"password\".\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the term is used in many ways and could\r\n easily be misunderstood.\r\n $ shielded enclosure\r\n (O) \"Room or container designed to attenuate electromagnetic\r\n radiation, acoustic signals, or emanations.\" [C4009] (See:\r\n emanation. Compare: SCIF.)\r\n $ short title\r\n (O) \"Identifying combination of letters and numbers assigned to\r\n certain items of COMSEC material to facilitate handling,\r\n accounting, and controlling.\" [C4009] (Compare: KMID, long title.)\r\nShirey Informational [Page 281]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 335 of 436\n\n$ shroud\r\n (D) /verb/ To encrypt a private key, possibly in concert with a\r\n policy that prevents the key from ever being available in\r\n cleartext form beyond a certain, well-defined security perimeter.\r\n [PKC12] (See: encrypt. Compare: seal, wrap.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term as defined here;\r\n the definition duplicates the meaning of other, standard terms.\r\n Instead, use \"encrypt\" or other terminology that is specific with\r\n regard to the mechanism being used.\r\n $ SHS\r\n (N) See: Secure Hash Standard.\r\n $ sign\r\n (I) Create a digital signature for a data object. (See: signer.)\r\n $ signal analysis\r\n (I) Gaining indirect knowledge (inference) of communicated data by\r\n monitoring and analyzing a signal that is emitted by a system and\r\n that contains the data but is not intended to communicate the\r\n data. (See: emanation. Compare: traffic analysis.)\r\n $ signal intelligence\r\n (I) The science and practice of extracting information from\r\n signals. (See: signal security.)\r\n $ signal security\r\n (N) (I) The science and practice of protecting signals. (See:\r\n cryptology, security.)\r\n Tutorial: The term \"signal\" denotes (a) communication in almost\r\n any form and also (b) emanations for other purposes, such as\r\n radar. Signal security is opposed by signal intelligence, and each\r\n discipline includes opposed sub-disciplines as follows [Kahn]:\r\n Signal Security Signal Intelligence\r\n ------------------------------ ---------------------------------\r\n 1. Communication Security 1. Communication Intelligence\r\n 1a. Cryptography 1a. Cryptanalysis\r\n 1b. Traffic Security 1b. Traffic Analysis\r\n 1c. Steganography 1c. Detection and Interception\r\n 2. Electronic Security 2. Electronic Intelligence\r\n 2a. Emission Security 2a. Electronic Reconnaissance\r\n 2b. Counter-Countermeasures 2b. Countermeasures\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 336 of 436\n\n------------------------------ ---------------------------------\r\nShirey Informational [Page 282]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ signature\r\n (O) A symbol or process adopted or executed by a system entity\r\n with present intention to declare that a data object is genuine.\r\n (See: digital signature, electronic signature.)\r\n $ signature certificate\r\n (I) A public-key certificate that contains a public key that is\r\n intended to be used for verifying digital signatures, rather than\r\n for encrypting data or performing other cryptographic functions.\r\n Tutorial: A v3 X.509 public-key certificate may have a \"keyUsage\"\r\n extension that indicates the purpose for which the certified\r\n public key is intended. (See: certificate profile.)\r\n $ signed receipt\r\n (I) An S/MIME service [R2634] that (a) provides, to the originator\r\n of a message, proof of delivery of the message and (b) enables the\r\n originator to demonstrate to a third party that the recipient was\r\n able to verify the signature of the original message.\r\n Tutorial: The receipt is bound to the original message by a\r\n signature; consequently, the service may be requested only for a\r\n message that is signed. The receipt sender may optionally also\r\n encrypt the receipt to provide confidentiality between the receipt\r\n sender and the receipt recipient.\r\n $ signer\r\n (N) A human being or organization entity that uses a private key\r\n to sign (i.e., create a digital signature on) a data object. [DSG]\r\n $ SILS\r\n (N) See: Standards for Interoperable LAN/MAN Security.\r\n $ simple authentication\r\n 1. (I) An authentication process that uses a password as the\r\n information needed to verify an identity claimed for an entity.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 337 of 436\n\n(Compare: strong authentication.)\r\n 2. (O) \"Authentication by means of simple password arrangements.\"\r\n [X509]\r\n $ Simple Authentication and Security Layer (SASL)\r\n (I) An Internet specification [R2222, R4422] for adding\r\n authentication service to connection-based protocols. (Compare:\r\n EAP, GSS-API.)\r\nShirey Informational [Page 283]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: To use SASL, a protocol includes a command for\r\n authenticating a user to a server and for optionally negotiating\r\n protection of subsequent protocol interactions. The command names\r\n a registered security mechanism. SASL mechanisms include Kerberos,\r\n GSS-API, S/KEY, and others. Some protocols that use SASL are IMAP4\r\n and POP3.\r\n $ Simple Key Management for Internet Protocols (SKIP)\r\n (I) A key-distribution protocol that uses hybrid encryption to\r\n convey session keys that are used to encrypt data in IP packets.\r\n (See: SKIP reference in [R2356].)\r\n Tutorial: SKIP was designed by Ashar Aziz and Whitfield Diffie at\r\n Sun Microsystems and proposed as the standard key management\r\n protocol for IPsec, but IKE was chosen instead. Although IKE is\r\n mandatory for an IPsec implementation, the use of SKIP is not\r\n excluded.\r\n SKIP uses the Diffie-Hellman-Merkle algorithm (or could use\r\n another key-agreement algorithm) to generate a key-encrypting key\r\n for use between two entities. A session key is used with a\r\n symmetric algorithm to encrypt data in one or more IP packets that\r\n are to be sent from one entity to the other. A symmetric KEK is\r\n established and used to encrypt the session key, and the encrypted\r\n session key is placed in a SKIP header that is added to each IP\r\n packet that is encrypted with that session key.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 338 of 436\n\n$ Simple Mail Transfer Protocol (SMTP)\r\n (I) A TCP-based, Application-Layer, Internet Standard protocol\r\n (RFC 821) for moving electronic mail messages from one computer to\r\n another.\r\n $ Simple Network Management Protocol (SNMP)\r\n (I) A (usually) UDP-based, Application-Layer, Internet Standard\r\n protocol (RFCs 3410-3418) for conveying management information\r\n between system components that act as managers and agents.\r\n $ Simple Public Key Infrastructure (SPKI)\r\n (I) A set of experimental concepts (RFCs 2692, 2693) that were\r\n proposed as alternatives to the concepts standardized in PKIX.\r\n $ simple security property\r\n (N) /formal model/ Property of a system whereby a subject has read\r\n access to an object only if the clearance of the subject dominates\r\n the classification of the object. See: Bell-LaPadula model.\r\nShirey Informational [Page 284]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ single sign-on\r\n 1. (I) An authentication subsystem that enables a user to access\r\n multiple, connected system components (such as separate hosts on a\r\n network) after a single login at only one of the components. (See:\r\n Kerberos.)\r\n 2. (O) /Liberty Alliance/ A security subsystem that enables a user\r\n identity to be authenticated at an identity provider -- i.e., at a\r\n service that authenticates and asserts the user's identity -- and\r\n then have that authentication be honored by other service\r\n providers.\r\n Tutorial: A single sign-on subsystem typically requires a user to\r\n log in once at the beginning of a session, and then during the\r\n session transparently grants access by the user to multiple,\r\n separately protected hosts, applications, or other system\r\n resources, without further login action by the user (unless, of\r\n course, the user logs out). Such a subsystem has the advantages of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 339 of 436\n\nbeing user friendly and enabling authentication to be managed\r\n consistently across an entire enterprise. Such a subsystem also\r\n has the disadvantage of requiring all the accessed components to\r\n depend on the security of the same authentication information.\r\n $ singular identity\r\n (I) See: secondary definition under \"identity\".\r\n $ site\r\n (I) A facility -- i.e., a physical space, room, or building\r\n together with its physical, personnel, administrative, and other\r\n safeguards -- in which system functions are performed. (See:\r\n node.)\r\n $ situation\r\n (I) See: security situation.\r\n $ SKEME\r\n (I) A key-distribution protocol from which features were adapted\r\n for IKE. [SKEME]\r\n $ SKIP\r\n (I) See: Simple Key Management for Internet Protocols.\r\n $ SKIPJACK\r\n (N) A type 2, 64-bit block cipher [SKIP, R2773] with a key size of\r\n 80 bits. (See: CAPSTONE, CLIPPER, FORTEZZA, Key Exchange\r\n Algorithm.)\r\nShirey Informational [Page 285]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: SKIPJACK was developed by NSA and formerly classified at\r\n the U.S. DoD \"Secret\" level. On 23 June 1998, NSA announced that\r\n SKIPJACK had been declassified.\r\n $ slot\r\n (O) /MISSI/ One of the FORTEZZA PC card storage areas that are\r\n each able to hold an X.509 certificate plus other data, including\r\n the private key that is associated with a public-key certificate.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 340 of 436\n\n$ smart card\r\n (I) A credit-card sized device containing one or more integrated\r\n circuit chips that perform the functions of a computer's central\r\n processor, memory, and input/output interface. (See: PC card,\r\n smart token.)\r\n Usage: Sometimes this term is used rather strictly to mean a card\r\n that closely conforms to the dimensions and appearance of the kind\r\n of plastic credit card issued by banks and merchants. At other\r\n times, the term is used loosely to include cards that are larger\r\n than credit cards, especially cards that are thicker, such as PC\r\n cards.\r\n $ smart token\r\n (I) A device that conforms to the definition of \"smart card\"\r\n except that rather than having the standard dimensions of a credit\r\n card, the token is packaged in some other form, such as a military\r\n dog tag or a door key. (See: smart card, cryptographic token.)\r\n $ SMI\r\n (I) See: security management infrastructure.\r\n $ SMTP\r\n (I) See: Simple Mail Transfer Protocol.\r\n $ smurf attack\r\n (D) /slang/ A denial-of-service attack that uses IP broadcast\r\n addressing to send ICMP ping packets with the intent of flooding a\r\n system. (See: fraggle attack, ICMP flood.)\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term.\r\n Derivation: The Smurfs are a fictional race of small, blue\r\n creatures that were created by a cartoonist. Perhaps the inventor\r\n of this attack thought that a swarm of ping packets resembled a\r\n gang of smurfs. (See: Deprecated Usage under \"Green Book\".)\r\nShirey Informational [Page 286]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 341 of 436\n\nTutorial: The attacker sends ICMP echo request (\"ping\") packets\r\n that appear to originate not from the attacker's own IP address,\r\n but from the address of the host or router that is the target of\r\n the attack. Each packet is addressed to an IP broadcast address,\r\n e.g., to all IP addresses in a given network. Thus, each echo\r\n request that is sent by the attacker results in many echo\r\n responses being sent to the target address. This attack can\r\n disrupt service at a particular host, at the hosts that depend on\r\n a particular router, or in an entire network.\r\n $ sneaker net\r\n (D) /slang/ A process that transfers data between systems only\r\n manually, under human control; i.e., a data transfer process that\r\n involves an air gap.\r\n Deprecated Term: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term.\r\n $ Snefru\r\n (N) A public-domain, cryptographic hash function (a.k.a. \"The\r\n Xerox Secure Hash Function\") designed by Ralph C. Merkle at Xerox\r\n Corporation. Snefru can produce either a 128-bit or 256-bit output\r\n (i.e., hash result). [Schn] (See: Khafre, Khufu.)\r\n $ sniffing\r\n (D) /slang/ Synonym for \"passive wiretapping\"; most often refers\r\n to capturing and examining the data packets carried on a LAN.\r\n (See: password sniffing.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it unnecessarily\r\n duplicates the meaning of a term that is better established. (See:\r\n Deprecated Usage under \"Green Book\".\r\n $ SNMP\r\n (I) See: Simple Network Management Protocol.\r\n $ social engineering\r\n (D) Euphemism for non-technical or low-technology methods, often\r\n involving trickery or fraud, that are used to attack information\r\n systems. Example: phishing.\r\n Deprecated Term: IDOCs SHOULD NOT use this term; it is too vague.\r\n Instead, use a term that is specific with regard to the means of\r\n attack, e.g., blackmail, bribery, coercion, impersonation,\r\n intimidation, lying, or theft.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 342 of 436\n\nShirey Informational [Page 287]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ SOCKS\r\n (I) An Internet protocol [R1928] that provides a generalized proxy\r\n server that enables client-server applications (e.g., TELNET, FTP,\r\n or HTTP; running over either TCP or UDP) to use the services of a\r\n firewall.\r\n Tutorial: SOCKS is layered under the IPS Application Layer and\r\n above the Transport Layer. When a client inside a firewall wishes\r\n to establish a connection to an object that is reachable only\r\n through the firewall, it uses TCP to connect to the SOCKS server,\r\n negotiates with the server for the authentication method to be\r\n used, authenticates with the chosen method, and then sends a relay\r\n request. The SOCKS server evaluates the request, typically based\r\n on source and destination addresses, and either establishes the\r\n appropriate connection or denies it.\r\n $ soft TEMPEST\r\n (O) The use of software techniques to reduce the radio frequency\r\n information leakage from computer displays and keyboards. [Kuhn]\r\n (See: TEMPEST.)\r\n $ soft token\r\n (D) A data object that is used to control access or authenticate\r\n authorization. (See: token.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term as defined here;\r\n the definition duplicates the meaning of other, standard terms.\r\n Instead, use \"attribute certificate\" or another term that is\r\n specific with regard to the mechanism being used.\r\n $ software\r\n (I) Computer programs (which are stored in and executed by\r\n computer hardware) and associated data (which also is stored in\r\n the hardware) that may be dynamically written or modified during\r\n execution. (Compare: firmware.)\r\n $ software error\r\n (I) /threat action/ See: secondary definitions under \"corruption\",\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 343 of 436\n\n\"exposure\", and \"incapacitation\".\r\n $ SORA\r\n (O) See: SSO-PIN ORA.\r\n $ source authentication\r\n (D) Synonym for \"data origin authentication\" or \"peer entity\r\n authentication\". (See: data origin authentication, peer entity\r\n authentication).\r\nShirey Informational [Page 288]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is\r\n ambiguous and, in either meaning, duplicates the meaning of\r\n internationally standardized terms. If the intent is to\r\n authenticate the original creator or packager of data received,\r\n then use \"data origin authentication\". If the intent is to\r\n authenticate the identity of the sender of data in the current\r\n instance, then use \"peer entity authentication\".\r\n $ source integrity\r\n (I) The property that data is trustworthy (i.e., worthy of\r\n reliance or trust), based on the trustworthiness of its sources\r\n and the trustworthiness of any procedures used for handling data\r\n in the system. Usage: a.k.a. Biba integrity. (See: integrity.\r\n Compare: correctness integrity, data integrity.)\r\n Tutorial: For this kind of integrity, there are formal models of\r\n unauthorized modification (see: Biba model) that logically\r\n complement the more familiar models of unauthorized disclosure\r\n (see: Bell-LaPadula model). In these models, objects are labeled\r\n to indicate the credibility of the data they contain, and there\r\n are rules for access control that depend on the labels.\r\n $ SP3\r\n (O) See: Security Protocol 3.\r\n $ SP4\r\n (O) See: Security Protocol 4.\r\n $ spam\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 344 of 436\n\n1a. (I) /slang verb/ To indiscriminately send unsolicited,\r\n unwanted, irrelevant, or inappropriate messages, especially\r\n commercial advertising in mass quantities.\r\n 1b. (I) /slang noun/ Electronic \"junk mail\". [R2635]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term in uppercase\r\n letters, because SPAM(trademark) is a trademark of Hormel Foods\r\n Corporation. Hormel says, \"We do not object to use of this slang\r\n term [spam] to describe [unsolicited advertising email], although\r\n we do object to the use of our product image in association with\r\n that term. Also, if the term is to be used, it SHOULD be used in\r\n all lower-case letters to distinguish it from our trademark SPAM,\r\n which SHOULD be used with all uppercase letters.\" (See: metadata.)\r\n Tutorial: In sufficient volume, spam can cause denial of service.\r\n (See: flooding.) According to Hormel, the term was adopted as a\r\n result of a Monty Python skit in which a group of Vikings sang a\r\n chorus of 'SPAM, SPAM, SPAM ...' in an increasing crescendo,\r\nShirey Informational [Page 289]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n drowning out other conversation. This lyric became a metaphor for\r\n the unsolicited advertising messages that threaten to overwhelm\r\n other discourse on the Internet.\r\n $ SPD\r\n (I) See: Security Policy Database.\r\n $ special access program (SAP)\r\n (O) /U.S. Government/ \"Sensitive program, [that is] approved in\r\n writing by a head of agency with [i.e., who has] original top\r\n secret classification authority, [and] that imposes need-to-know\r\n and access controls beyond those normally provided for access to\r\n Confidential, Secret, or Top Secret information. The level of\r\n controls is based on the criticality of the program and the\r\n assessed hostile intelligence threat. The program may be an\r\n acquisition program, an intelligence program, or an operations and\r\n support program.\" [C4009] (See: formal access approval, SCI.\r\n Compare: collateral information.)\r\n $ SPI\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 345 of 436\n\n(I) See: Security Parameters Index.\r\n $ SPKI\r\n (I) See: Simple Public Key Infrastructure.\r\n $ split key\r\n (I) A cryptographic key that is generated and distributed as two\r\n or more separate data items that individually convey no knowledge\r\n of the whole key that results from combining the items. (See: dual\r\n control, split knowledge.)\r\n $ split knowledge\r\n 1. (I) A security technique in which two or more entities\r\n separately hold data items that individually do not convey\r\n knowledge of the information that results from combining the\r\n items. (See: dual control, split key.)\r\n 2. (O) \"A condition under which two or more entities separately\r\n have key components [that] individually convey no knowledge of the\r\n plaintext key [that] will be produced when the key components are\r\n combined in the cryptographic module.\" [FP140]\r\n $ spoof\r\n (I) /threat action/ See: secondary definition under \"masquerade\".\r\n $ spoofing attack\r\n (I) Synonym for \"masquerade attack\".\r\nShirey Informational [Page 290]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ spread spectrum\r\n (N) A TRANSEC technique that transmits a signal in a bandwidth\r\n much greater than the transmitted information needs. [F1037]\r\n Example: frequency hopping.\r\n Tutorial: Usually uses a sequential, noise-like signal structure\r\n to spread the normally narrowband information signal over a\r\n relatively wide band of frequencies. The receiver correlates the\r\n signals to retrieve the original information signal. This\r\n technique decreases potential interference to other receivers,\r\n while achieving data confidentiality and increasing immunity of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 346 of 436\n\nspread spectrum receivers to noise and interference.\r\n $ spyware\r\n (D) /slang/ Software that an intruder has installed\r\n surreptitiously on a networked computer to gather data from that\r\n computer and send it through the network to the intruder or some\r\n other interested party. (See: malicious logic, Trojan horse.)\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the term is used in many ways and could\r\n easily be misunderstood.\r\n Tutorial: Some examples of the types of data that might be\r\n gathered by spyware are application files, passwords, email\r\n addresses, usage histories, and keystrokes. Some examples of\r\n motivations for gathering the data are blackmail, financial fraud,\r\n identity theft, industrial espionage, market research, and\r\n voyeurism.\r\n $ SSH(trademark)\r\n (N) See: Secure Shell(trademark).\r\n $ SSL\r\n (I) See: Secure Sockets Layer.\r\n $ SSO\r\n (I) See: system security officer.\r\n $ SSO PIN\r\n (O) /MISSI/ One of two PINs that control access to the functions\r\n and stored data of a FORTEZZA PC card. Knowledge of the SSO PIN\r\n enables a card user to perform the FORTEZZA functions intended for\r\n use by an end user and also the functions intended for use by a\r\n MISSI CA. (See: user PIN.)\r\nShirey Informational [Page 291]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ SSO-PIN ORA (SORA)\r\n (O) /MISSI/ A MISSI organizational RA that operates in a mode in\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 347 of 436\n\nwhich the ORA performs all card management functions and,\r\n therefore, requires knowledge of the SSO PIN for FORTEZZA PC cards\r\n issued to end users.\r\n $ Standards for Interoperable LAN/MAN Security (SILS)\r\n 1. (N) The IEEE 802.10 standards committee. (See: [FP191].)\r\n 2. (N) A set of IEEE standards, which has eight parts: (a) Model,\r\n including security management, (b) Secure Data Exchange protocol,\r\n (c) Key Management, (d) [has been incorporated in (a)], (e) SDE\r\n Over Ethernet 2.0, (f) SDE Sublayer Management, (g) SDE Security\r\n Labels, and (h) SDE PICS Conformance. Parts b, e, f, g, and h are\r\n incorporated in IEEE Standard 802.10-1998.\r\n $ star property\r\n (N) See: *-property.\r\n $ Star Trek attack\r\n (D) /slang/ An attack that penetrates your system where no attack\r\n has ever gone before.\r\n Deprecated Usage: IDOCs SHOULD NOT use this term; it is a joke for\r\n Trekkies. (See: Deprecated Usage under \"Green Book\".)\r\n $ static\r\n (I) /adjective/ Refers to a cryptographic key or other parameter\r\n that is relatively long-lived. (Compare: ephemeral.)\r\n $ steganography\r\n (I) Methods of hiding the existence of a message or other data.\r\n This is different than cryptography, which hides the meaning of a\r\n message but does not hide the message itself. Examples: For\r\n classic, physical methods, see [Kahn]; for modern, digital\r\n methods, see [John]. (See: cryptology. Compare: concealment\r\n system, digital watermarking.)\r\n $ storage channel\r\n (I) See: covert storage channel.\r\n $ storage key\r\n (I) A cryptographic key used by a device for protecting\r\n information that is being maintained in the device, as opposed to\r\n protecting information that is being transmitted between devices.\r\n (See: cryptographic token, token copy. Compare: traffic key.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 348 of 436\n\nShirey Informational [Page 292]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ stream cipher\r\n (I) An encryption algorithm that breaks plain text into a stream\r\n of successive elements (usually, bits) and encrypts the n-th\r\n plaintext element with the n-th element of a parallel key stream,\r\n thus converting the plaintext stream into a ciphertext stream.\r\n [Schn] (See: block cipher.)\r\n $ stream integrity service\r\n (I) A data integrity service that preserves integrity for a\r\n sequence of data packets, including both (a) bit-by-bit datagram\r\n integrity of each individual packet in the set and (b) packet-by-\r\n packet sequential integrity of the set as a whole. (See: data\r\n integrity. Compare: datagram integrity service.)\r\n Tutorial: Some internetwork applications need only datagram\r\n integrity, but others require that an entire stream of packets be\r\n protected against insertion, reordering, deletion, and delay:\r\n - \"Insertion\": The destination receives an additional packet that\r\n was not sent by the source.\r\n - \"Reordering\": The destination receives packets in a different\r\n order than that in which they were sent by the source.\r\n - \"Deletion\": A packet sent by the source is not ever delivered\r\n to the intended destination.\r\n - \"Delay\": A packet is detained for some period of time at a\r\n relay, thus hampering and postponing the packet's normal timely\r\n delivery from source to destination.\r\n $ strength\r\n 1. (I) /cryptography/ A cryptographic mechanism's level of\r\n resistance to attacks [R3766]. (See: entropy, strong, work\r\n factor.)\r\n 2. (N) /Common Criteria/ \"Strength of function\" is a\r\n \"qualification of a TOE security function expressing the minimum\r\n efforts assumed necessary to defeat its expected security behavior\r\n by directly attacking its underlying security mechanisms\": (See:\r\n strong.)\r\n - Basic: \"A level of the TOE strength of function where analysis\r\n shows that the function provides adequate protection against\r\n casual breach of TOE security by attackers possessing a low\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 349 of 436\n\nattack potential.\"\r\n - Medium: \"... against straightforward or intentional breach ...\r\n by attackers possessing a moderate attack potential.\"\r\n - High: \"... against deliberately planned or organized breach ...\r\n by attackers possessing a high attack potential.\"\r\nShirey Informational [Page 293]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ strong\r\n 1. (I) /cryptography/ Used to describe a cryptographic algorithm\r\n that would require a large amount of computational power to defeat\r\n it. (See: strength, work factor, weak key.)\r\n 2. (I) /COMPUSEC/ Used to describe a security mechanism that would\r\n be difficult to defeat. (See: strength, work factor.)\r\n $ strong authentication\r\n 1. (I) An authentication process that uses a cryptographic\r\n security mechanism -- particularly public-key certificates -- to\r\n verify the identity claimed for an entity. (Compare: simple\r\n authentication.)\r\n 2. (O) \"Authentication by means of cryptographically derived\r\n credentials.\" [X509]\r\n $ subject\r\n 1a. (I) A process in a computer system that represents a principal\r\n and that executes with the privileges that have been granted to\r\n that principal. (Compare: principal, user.)\r\n 1b. (I) /formal model/ A system entity that causes information to\r\n flow among objects or changes the system state; technically, a\r\n process-domain pair. A subject may itself be an object relative to\r\n some other subject; thus, the set of subjects in a system is a\r\n subset of the set of objects. (See: Bell-LaPadula model, object.)\r\n 2. (I) /digital certificate/ The name (of a system entity) that is\r\n bound to the data items in a digital certificate; e.g., a DN that\r\n is bound to a key in a public-key certificate. (See: X.509.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 350 of 436\n\n$ subject CA\r\n (D) The CA that is the subject of a cross-certificate issued by\r\n another CA. [X509] (See: cross-certification.)\r\n Deprecated Term: IDOCs SHOULD NOT use this term because it is not\r\n widely known and could be misunderstood. Instead, say \"the CA that\r\n is the subject of the cross-certificate\".\r\n $ subnetwork\r\n (N) An OSI term for a system of packet relays and connecting links\r\n that implement OSIRM layer 2 or 3 to provide a communication\r\n service that interconnects attached end systems. Usually, the\r\n relays are all of the same type (e.g., X.25 packet switches, or\r\n interface units in an IEEE 802.3 LAN). (See: gateway, internet,\r\n router.)\r\nShirey Informational [Page 294]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ subordinate CA (SCA)\r\n 1. (I) A CA whose public-key certificate is issued by another\r\n (superior) CA. (See: certification hierarchy. Compare: cross-\r\n certification.)\r\n 2. (O) /MISSI/ The fourth-highest (i.e., bottom) level of a MISSI\r\n certification hierarchy; a MISSI CA whose public-key certificate\r\n is signed by a MISSI CA rather than by a MISSI PCA. A MISSI SCA is\r\n the administrative authority for a subunit of an organization,\r\n established when it is desirable to organizationally distribute or\r\n decentralize the CA service. The term refers both to that\r\n authoritative office or role, and to the person who fills that\r\n office. A MISSI SCA registers end users and issues their\r\n certificates and may also register ORAs, but may not register\r\n other CAs. An SCA periodically issues a CRL.\r\n $ subordinate DN\r\n (I) An X.500 DN is subordinate to another X.500 DN if it begins\r\n with a set of attributes that is the same as the entire second DN\r\n except for the terminal attribute of the second DN (which is\r\n usually the name of a CA). For example, the DN \u003cC=FooLand, O=Gov,\r\n OU=Treasurer, CN=DukePinchpenny\u003e is subordinate to the DN\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 351 of 436\n\n\u003cC=FooLand, O=Gov, CN=KingFooCA\u003e.\r\n $ subscriber\r\n (I) /PKI/ A user that is registered in a PKI and, therefore, can\r\n be named in the \"subject\" field of a certificate issued by a CA in\r\n that PKI. (See: registration, user.)\r\n Usage: This term is needed to distinguish registered users from\r\n two other kinds of PKI users:\r\n - Users that access the PKI but are not identified to it: For\r\n example, a relying party may access a PKI repository to obtain\r\n the certificate of some other party. (See: access.)\r\n - Users that do not access the PKI: For example, a relying party\r\n (see: certificate user) may use a digital certificate that was\r\n obtained from a database that is not part of the PKI that\r\n issued the certificate.\r\n $ substitution\r\n 1. (I) /cryptography/ A method of encryption in which elements of\r\n the plain text retain their sequential position but are replaced\r\n by elements of cipher text. (Compare: transposition.)\r\n 2. (I) /threat action/ See: secondary definition under\r\n \"falsification\".\r\nShirey Informational [Page 295]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ subsystem\r\n (I) A collection of related system components that together\r\n perform a system function or deliver a system service.\r\n $ superencryption\r\n (I) An encryption operation for which the plaintext input to be\r\n transformed is the ciphertext output of a previous encryption\r\n operation. (Compare: hybrid encryption.)\r\n $ superuser\r\n (I) /UNIX/ Synonym for \"root\".\r\n $ survivability\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 352 of 436\n\n(I) The ability of a system to remain in operation or existence\r\n despite adverse conditions, including natural occurrences,\r\n accidental actions, and attacks. (Compare: availability,\r\n reliability.)\r\n $ swIPe\r\n (I) An encryption protocol for IP that provides confidentiality,\r\n integrity, and authentication and can be used for both end-to-end\r\n and intermediate-hop security. [Ioan] (Compare: IPsec.)\r\n Tutorial: The swIPe protocol is an IP predecessor that is\r\n concerned only with encryption mechanisms; policy and key\r\n management are handled outside the protocol.\r\n $ syllabary\r\n (N) /encryption/ A list of individual letters, combinations of\r\n letters, or syllables, with their equivalent code groups, used for\r\n spelling out proper names or other unusual words that are not\r\n present in the basic vocabulary (i.e., are not in the codebook) of\r\n a code used for encryption.\r\n $ symmetric cryptography\r\n (I) A branch of cryptography in which the algorithms use the same\r\n key for both of two counterpart cryptographic operations (e.g.,\r\n encryption and decryption). (See: asymmetric cryptography.\r\n Compare: secret-key cryptography.)\r\n Tutorial: Symmetric cryptography has been used for thousands of\r\n years [Kahn]. A modern example is AES.\r\n Symmetric cryptography has a disadvantage compared to asymmetric\r\n cryptography with regard to key distribution. For example, when\r\n Alice wants to ensure confidentiality for data she sends to Bob,\r\n she encrypts the data with a key, and Bob uses the same key to\r\n decrypt. However, keeping the shared key secret entails both cost\r\nShirey Informational [Page 296]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n and risk when the key is distributed to both Alice and Bob. (See:\r\n key distribution, key management.)\r\n $ symmetric key\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 353 of 436\n\n(I) A cryptographic key that is used in a symmetric cryptographic\r\n algorithm. (See: symmetric cryptography.)\r\n $ SYN flood\r\n (I) A denial-of-service attack that sends a large number of TCP\r\n SYN (synchronize) packets to a host with the intent of disrupting\r\n the operation of that host. (See: blind attack, flooding.)\r\n Tutorial: This attack seeks to exploit a vulnerability in the TCP\r\n specification or in a TCP implementation. Normally, two hosts use\r\n a three-way exchange of packets to establish a TCP connection: (a)\r\n host 1 requests a connection by sending a SYN packet to host 2;\r\n (b) host 2 replies by sending a SYN-ACK (acknowledgement) packet\r\n to host 1; and (c) host 1 completes the connection by sending an\r\n ACK packet to host 2. To attack host 2, host 1 can send a series\r\n of TCP SYNs, each with a different phony source address. ([R2827]\r\n discusses how to use packet filtering to prevent such attacks from\r\n being launched from behind an Internet service provider's\r\n aggregation point.) Host 2 treats each SYN as a request from a\r\n separate host, replies to each with a SYN-ACK, and waits to\r\n receive the matching ACKs. (The attacker can use random or\r\n unreachable sources addresses in the SYN packets, or can use\r\n source addresses that belong to third parties, that then become\r\n secondary victims.)\r\n For each SYN-ACK that is sent, the TCP process in host 2 needs\r\n some memory space to store state information while waiting for the\r\n matching ACK to be returned. If the matching ACK never arrives at\r\n host 2, a timer associated with the pending SYN-ACK will\r\n eventually expire and release the space. But if host 1 (or a\r\n cooperating group of hosts) can rapidly send many SYNs to host 2,\r\n host 2 will need to store state information for many pending SYN-\r\n ACKs and may run out of space. This can prevent host 2 from\r\n responding to legitimate connection requests from other hosts or\r\n even, if there are flaws in host 2's TCP implementation, crash\r\n when the available space is exhausted.\r\n $ synchronization\r\n (I) Any technique by which a receiving (decrypting) cryptographic\r\n process attains an internal state that matches the transmitting\r\n (encrypting) process, i.e., has the appropriate keying material to\r\n process the cipher text and is correctly initialized to do so.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 354 of 436\n\nShirey Informational [Page 297]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ system\r\n (I) Synonym for \"information system\".\r\n Usage: This is a generic definition, and is the one with which the\r\n term is used in this Glossary. However, IDOCs that use the term,\r\n especially IDOCs that are protocol specifications, SHOULD state a\r\n more specific definition. Also, IDOCs that specify security\r\n features, services, and assurances need to define which system\r\n components and system resources are inside the applicable security\r\n perimeter and which are outside. (See: security architecture.)\r\n $ system architecture\r\n (N) The structure of system components, their relationships, and\r\n the principles and guidelines governing their design and evolution\r\n over time. [DoD10] (Compare: security architecture.)\r\n $ system component\r\n 1. (I) A collection of system resources that (a) forms a physical\r\n or logical part of the system, (b) has specified functions and\r\n interfaces, and (c) is treated (e.g., by policies or\r\n specifications) as existing independently of other parts of the\r\n system. (See: subsystem.)\r\n 2. (O) /ITSEC/ An identifiable and self-contained part of a TOE.\r\n Usage: Component is a relative term because components may be\r\n nested; i.e., one component of a system may be a part of another\r\n component of that system.\r\n Tutorial: Components can be characterized as follows:\r\n - A \"physical component\" has mass and takes up space.\r\n - A \"logical component\" is an abstraction used to manage and\r\n coordinate aspects of the physical environment, and typically\r\n represents a set of states or capabilities of the system.\r\n $ system entity\r\n (I) An active part of a system -- a person, a set of persons\r\n (e.g., some kind of organization), an automated process, or a set\r\n of processes (see: subsystem) -- that has a specific set of\r\n capabilities. (Compare: subject, user.)\r\n $ system high\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 355 of 436\n\n(I) The highest security level at which a system operates, or is\r\n capable of operating, at a particular time or in a particular\r\n environment. (See: system-high security mode.)\r\nShirey Informational [Page 298]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ system-high security mode\r\n (I) A mode of system operation wherein all users having access to\r\n the system possess all necessary authorizations (both security\r\n clearance and formal access approval) for all data handled by the\r\n system, but some users might not have need-to-know for all the\r\n data. (See: /system operation/ under \"mode\", formal access\r\n approval, protection level, security clearance.)\r\n Usage: Usually abbreviated as \"system-high mode\". This mode was\r\n defined in U.S. DoD policy that applied to system accreditation,\r\n but the term is widely used outside the Government.\r\n $ system integrity\r\n 1. (I) An attribute or quality \"that a system has when it can\r\n perform its intended function in a unimpaired manner, free from\r\n deliberate or inadvertent unauthorized manipulation.\" [C4009,\r\n NCS04] (See: recovery, system integrity service.)\r\n 2. (D) \"Quality of an [information system] reflecting the logical\r\n correctness and reliability of the operating system; the logical\r\n completeness of the hardware and software implementing the\r\n protection mechanisms; and the consistency of the data structures\r\n and occurrence of the stored data.\" [from an earlier version of\r\n C4009]\r\n Deprecated Definition: IDOCs SHOULD NOT use definition 2 because\r\n it mixes several concepts in a potentially misleading way.\r\n Instead, IDOCs should use the term with definition 1 and,\r\n depending on what is meant, couple the term with additional, more\r\n specifically descriptive and informative terms, such as\r\n \"correctness\", \"reliability\", and \"data integrity\".\r\n $ system integrity service\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 356 of 436\n\n(I) A security service that protects system resources in a\r\n verifiable manner against unauthorized or accidental change, loss,\r\n or destruction. (See: system integrity.)\r\n $ system low\r\n (I) The lowest security level supported by a system at a\r\n particular time or in a particular environment. (Compare: system\r\n high.)\r\n $ system resource\r\n (I) Data contained in an information system; or a service provided\r\n by a system; or a system capacity, such as processing power or\r\n communication bandwidth; or an item of system equipment (i.e.,\r\nShirey Informational [Page 299]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n hardware, firmware, software, or documentation); or a facility\r\n that houses system operations and equipment. (See: system\r\n component.)\r\n $ system security officer (SSO)\r\n (I) A person responsible for enforcement or administration of the\r\n security policy that applies to a system. (Compare: manager,\r\n operator.)\r\n $ system user\r\n (I) A system entity that consumes a product or service provided by\r\n the system, or that accesses and employs system resources to\r\n produce a product or service of the system. (See: access, [R2504].\r\n Compare: authorized user, manager, operator, principal, privileged\r\n user, subject, subscriber, system entity, unauthorized user.)\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the term is used in many ways and could easily be\r\n misunderstood:\r\n - This term usually refers to an entity that has been authorized\r\n to access the system, but the term sometimes is used without\r\n regard for whether access is authorized.\r\n - This term usually refers to a living human being acting either\r\n personally or in an organizational role. However, the term also\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 357 of 436\n\nmay refer to an automated process in the form of hardware,\r\n software, or firmware; to a set of persons; or to a set of\r\n processes.\r\n - IDOCs SHOULD NOT use the term to refer to a mixed set\r\n containing both persons and processes. This exclusion is\r\n intended to prevent situations that might cause a security\r\n policy to be interpreted in two different and conflicting ways.\r\n A system user can be characterized as direct or indirect:\r\n - \"Passive user\": A system entity that is (a) outside the\r\n system's security perimeter *and* (b) can receive output from\r\n the system but cannot provide input or otherwise interact with\r\n the system.\r\n - \"Active user\": A system entity that is (a) inside the system's\r\n security perimeter *or* (b) can provide input or otherwise\r\n interact with the system.\r\n $ TACACS\r\n (I) See: Terminal Access Controller (TAC) Access Control System.\r\n $ TACACS+\r\n (I) A TCP-based protocol that improves on TACACS by separating the\r\n functions of authentication, authorization, and accounting and by\r\n encrypting all traffic between the network access server and\r\nShirey Informational [Page 300]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n authentication server. TACACS+ is extensible to allow any\r\n authentication mechanism to be used with TACACS+ clients.\r\n $ tamper\r\n (I) Make an unauthorized modification in a system that alters the\r\n system's functioning in a way that degrades the security services\r\n that the system was intended to provide. (See: QUADRANT. Compare:\r\n secondary definitions under \"corruption\" and \"misuse\".)\r\n $ tamper-evident\r\n (I) A characteristic of a system component that provides evidence\r\n that an attack has been attempted on that component or system.\r\n Usage: Usually involves physical evidence. (See: tamper.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 358 of 436\n\n$ tamper-resistant\r\n (I) A characteristic of a system component that provides passive\r\n protection against an attack. (See: tamper.)\r\n Usage: Usually involves physical means of protection.\r\n $ tampering\r\n (I) /threat action/ See: secondary definitions under \"corruption\"\r\n and \"misuse\".\r\n $ target of evaluation (TOE)\r\n (N) /Common Criteria/ An information technology product or system\r\n that is the subject of a security evaluation, together with the\r\n product's associated administrator and user documentation.\r\n (Compare: protection profile.)\r\n Tutorial: The security characteristics of the target of evaluation\r\n (TOE) are described in specific terms by a corresponding security\r\n target, or in more general terms by a protection profile. In\r\n Common Criteria philosophy, it is important that a TOE be\r\n evaluated against the specific set of criteria expressed in the\r\n target. This evaluation consists of rigorous analysis and testing\r\n performed by an accredited, independent laboratory. The scope of a\r\n TOE evaluation is set by the EAL and other requirements specified\r\n in the target. Part of this process is an evaluation of the target\r\n itself, to ensure that it is correct, complete, and internally\r\n consistent and can be used as the baseline for the TOE evaluation.\r\n $ TCB\r\n (N) See: trusted computing base.\r\n $ TCC field\r\n (I) See: Transmission Control Code field.\r\nShirey Informational [Page 301]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ TCG\r\n (N) See: Trusted Computing Group.\r\n $ TCP\r\n (I) See: Transmission Control Protocol.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 359 of 436\n\n$ TCP/IP\r\n (I) Synonym for \"Internet Protocol Suite\".\r\n $ TCSEC\r\n (N) See: Trusted Computer System Evaluation Criteria. (Compare:\r\n TSEC.)\r\n $ TDEA\r\n (I) See: Triple Data Encryption Algorithm.\r\n $ teardrop attack\r\n (D) /slang/ A denial-of-service attack that sends improperly\r\n formed IP packet fragments with the intent of causing the\r\n destination system to fail.\r\n Deprecated Term: IDOCs that use this term SHOULD state a\r\n definition for it because the term is often used imprecisely and\r\n could easily be misunderstood. (See: Deprecated Usage under \"Green\r\n Book\".)\r\n $ technical non-repudiation\r\n (I) See: (secondary definition under) non-repudiation.\r\n $ technical security\r\n (I) Security mechanisms and procedures that are implemented in and\r\n executed by computer hardware, firmware, or software to provide\r\n automated protection for a system. (See: security architecture.\r\n Compare: administrative security.)\r\n $ Telecommunications Security Word System (TSEC)\r\n (O) /U.S. Government/ A terminology for designating\r\n telecommunication security equipment. (Compare: TCSEC.)\r\n Tutorial: A TSEC designator has the following parts:\r\n - Prefix \"TSEC/\" for items and systems, or suffix \"/TSEC\" for\r\n assemblies. (Often omitted when the context is clear.)\r\n - First letter, for function: \"C\" COMSEC equipment system, \"G\"\r\n general purpose, \"K\" cryptographic, \"H\" crypto-ancillary, \"M\"\r\n manufacturing, \"N\" noncryptographic, \"S\" special purpose.\r\n - Second letter, for type or purpose: \"G\" key generation, \"I\"\r\n data transmission, \"L\" literal conversion, \"N\" signal\r\n conversion, \"O\" multipurpose, \"P\" materials production, \"S\"\r\nShirey Informational [Page 302]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 360 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n special purpose, \"T\" testing or checking, \"U\" television, \"W\"\r\n teletypewriter, \"X\" facsimile, \"Y\" speech.\r\n - Optional third letter, used only in designations of assemblies,\r\n for type or purpose: \"A\" advancing, \"B\" base or cabinet, \"C\"\r\n combining, \"D\" drawer or panel, \"E\" strip or chassis, \"F\" frame\r\n or rack, \"G\" key generator, \"H\" keyboard, \"I\" translator or\r\n reader, \"J\" speech processing, \"K\" keying or permuting, \"L\"\r\n repeater, \"M\" memory or storage, \"O\" observation, \"P\" power\r\n supply or converter, \"R\" receiver, \"S\" synchronizing, \"T\"\r\n transmitter, \"U\" printer, \"V\" removable COMSEC component, \"W\"\r\n logic programmer/programming, \"X\" special purpose.\r\n - Model number, usually two or three digits, assigned\r\n sequentially within each letter combination (e.g., KG-34, KG-\r\n 84).\r\n - Optional suffix letter, used to designate a version. First\r\n version has no letter, next version has \"A\" (e.g., KG-84, KG-\r\n 84A), etc.\r\n $ TELNET\r\n (I) A TCP-based, Application-Layer, Internet Standard protocol\r\n (RFC 854) for remote login from one host to another.\r\n $ TEMPEST\r\n 1. (N) Short name for technology and methods for protecting\r\n against data compromise due to electromagnetic emanations from\r\n electrical and electronic equipment. [Army, Russ] (See:\r\n inspectable space, soft TEMPEST, TEMPEST zone. Compare: QUADRANT)\r\n 2. (O) /U.S. Government/ \"Short name referring to investigation,\r\n study, and control of compromising emanations from IS equipment.\"\r\n [C4009]\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as a synonym for\r\n \"electromagnetic emanations security\"; instead, use EMSEC. Also,\r\n the term is NOT an acronym for Transient Electromagnetic Pulse\r\n Surveillance Technology.\r\n Tutorial: The U.S. Federal Government issues security policies\r\n that (a) state specifications and standards for techniques to\r\n reduce the strength of emanations from systems and reduce the\r\n ability of unauthorized parties to receive and make use of\r\n emanations and (b) state rules for applying those techniques.\r\n Other nations presumably do the same.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 361 of 436\n\n$ TEMPEST zone\r\n (O) \"Designated area [i.e., a physical volume] within a facility\r\n where equipment with appropriate TEMPEST characteristics ... may\r\nShirey Informational [Page 303]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n be operated.\" [C4009] (See: emanation security, TEMPEST. Compare:\r\n control zone, inspectable space.)\r\n Tutorial: The strength of an electromagnetic signal decreases in\r\n proportion to the square of the distance between the source and\r\n the receiver. Therefore, EMSEC for electromagnetic signals can be\r\n achieved by a combination of (a) reducing the strength of\r\n emanations to a defined level and (b) establishing around that\r\n equipment an appropriately sized physical buffer zone from which\r\n unauthorized entities are excluded. By making the zone large\r\n enough, it is possible to limit the signal strength available to\r\n entities outside the zone to a level lower than can be received\r\n and read with known, state-of-the-art methods. Typically, the need\r\n for and size of a TEMPEST zone established by a security policy\r\n depends not only on the measured level of signal emitted by\r\n equipment, but also on the perceived threat level in the\r\n equipment's environment.\r\n $ Terminal Access Controller (TAC) Access Control System (TACACS)\r\n (I) A UDP-based authentication and access control protocol [R1492]\r\n in which a network access server receives an identifier and\r\n password from a remote terminal and passes them to a separate\r\n authentication server for verification. (See: TACACS+.)\r\n Tutorial: TACACS can provide service not only for network access\r\n servers but also routers and other networked computing devices via\r\n one or more centralized authentication servers. TACACS was\r\n originally developed for ARPANET and has evolved for use in\r\n commercial equipment.\r\n $ TESS\r\n (I) See: The Exponential Encryption System.\r\n $ The Exponential Encryption System (TESS)\r\n (I) A system of separate but cooperating cryptographic mechanisms\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 362 of 436\n\nand functions for the secure authenticated exchange of\r\n cryptographic keys, the generation of digital signatures, and the\r\n distribution of public keys. TESS uses asymmetric cryptography,\r\n based on discrete exponentiation, and a structure of self-\r\n certified public keys. [R1824]\r\n $ theft\r\n (I) /threat action/ See: secondary definitions under\r\n \"interception\" and \"misappropriation\".\r\n $ threat\r\n 1a. (I) A potential for violation of security, which exists when\r\n there is an entity, circumstance, capability, action, or event\r\nShirey Informational [Page 304]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n that could cause harm. (See: dangling threat, INFOCON level,\r\n threat action, threat agent, threat consequence. Compare: attack,\r\n vulnerability.)\r\n 1b. (N) Any circumstance or event with the potential to adversely\r\n affect a system through unauthorized access, destruction,\r\n disclosure, or modification of data, or denial of service. [C4009]\r\n (See: sensitive information.)\r\n Usage: (a) Frequently misused with the meaning of either \"threat\r\n action\" or \"vulnerability\". (b) In some contexts, \"threat\" is used\r\n more narrowly to refer only to intelligent threats; for example,\r\n see definition 2 below. (c) In some contexts, \"threat\" is used\r\n more broadly to cover both definition 1 and other concepts, such\r\n as in definition 3 below.\r\n Tutorial: A threat is a possible danger that might exploit a\r\n vulnerability. Thus, a threat may be intentional or not:\r\n - \"Intentional threat\": A possibility of an attack by an\r\n intelligent entity (e.g., an individual cracker or a criminal\r\n organization).\r\n - \"Accidental threat\": A possibility of human error or omission,\r\n unintended equipment malfunction, or natural disaster (e.g.,\r\n fire, flood, earthquake, windstorm, and other causes listed in\r\n [FP031]).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 363 of 436\n\nThe Common Criteria characterizes a threat in terms of (a) a\r\n threat agent, (b) a presumed method of attack, (c) any\r\n vulnerabilities that are the foundation for the attack, and (d)\r\n the system resource that is attacked. That characterization agrees\r\n with the definitions in this Glossary (see: diagram under\r\n \"attack\").\r\n 2. (O) The technical and operational ability of a hostile entity\r\n to detect, exploit, or subvert a friendly system and the\r\n demonstrated, presumed, or inferred intent of that entity to\r\n conduct such activity.\r\n Tutorial: To be likely to launch an attack, an adversary must have\r\n (a) a motive to attack, (b) a method or technical ability to make\r\n the attack, and (c) an opportunity to appropriately access the\r\n targeted system.\r\n 3. (D) \"An indication of an impending undesirable event.\" [Park]\r\n Deprecated Definition: IDOCs SHOULD NOT use this term with\r\n definition 3 because the definition is ambiguous; the definition\r\n was intended to include the following three meanings:\r\nShirey Informational [Page 305]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - \"Potential threat\": A possible security violation; i.e., the\r\n same as definition 1.\r\n - \"Active threat\": An expression of intent to violate security.\r\n (Context usually distinguishes this meaning from the previous\r\n one.)\r\n - \"Accomplished threat\" or \"actualized threat\": That is, a threat\r\n action. Deprecated Usage: IDOCs SHOULD NOT use the term\r\n \"threat\" with this meaning; instead, use \"threat action\".\r\n $ threat action\r\n (I) A realization of a threat, i.e., an occurrence in which system\r\n security is assaulted as the result of either an accidental event\r\n or an intentional act. (See: attack, threat, threat consequence.)\r\n Tutorial: A complete security architecture deals with both\r\n intentional acts (i.e., attacks) and accidental events [FP031].\r\n (See: various kinds of threat actions defined under the four kinds\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 364 of 436\n\nof \"threat consequence\".)\r\n $ threat agent\r\n (I) A system entity that performs a threat action, or an event\r\n that results in a threat action.\r\n $ threat analysis\r\n (I) An analysis of the threat actions that might affect a system,\r\n primarily emphasizing their probability of occurrence but also\r\n considering their resulting threat consequences. Example: RFC\r\n 3833. (Compare: risk analysis.)\r\n $ threat consequence\r\n (I) A security violation that results from a threat action.\r\n Tutorial: The four basic types of threat consequence are\r\n \"unauthorized disclosure\", \"deception\", \"disruption\", and\r\n \"usurpation\". (See main Glossary entries of each of these four\r\n terms for lists of the types of threat actions that can result in\r\n these consequences.)\r\n $ thumbprint\r\n 1. (I) A pattern of curves formed by the ridges on the tip of a\r\n thumb. (See: biometric authentication, fingerprint.)\r\n 2. (D) Synonym for some type of \"hash result\". (See: biometric\r\n authentication. Compare: fingerprint.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term with definition 2\r\n because that meaning mixes concepts in a potentially misleading\r\n way.\r\nShirey Informational [Page 306]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ ticket\r\n (I) Synonym for \"capability token\".\r\n Tutorial: A ticket is usually granted by a centralized access\r\n control server (ticket-granting agent) to authorize access to a\r\n system resource for a limited time. Tickets can be implemented\r\n with either symmetric cryptography (see: Kerberos) or asymmetric\r\n cryptography (see: attribute certificate).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 365 of 436\n\n$ tiger team\r\n (O) A group of evaluators employed by a system's managers to\r\n perform penetration tests on the system.\r\n Deprecated Usage: It is likely that other cultures use different\r\n metaphors for this concept. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. (See: Deprecated\r\n Usage under \"Green Book\".)\r\n $ time stamp\r\n 1. (I) /noun/ With respect to a data object, a label or marking in\r\n which is recorded the time (time of day or other instant of\r\n elapsed time) at which the label or marking was affixed to the\r\n data object. (See: Time-Stamp Protocol.)\r\n 2. (O) /noun/ \"With respect to a recorded network event, a data\r\n field in which is recorded the time (time of day or other instant\r\n of elapsed time) at which the event took place.\" [A1523]\r\n Tutorial: A time stamp can be used as evidence to prove that a\r\n data object existed (or that an event occurred) at or before a\r\n particular time. For example, a time stamp might be used to prove\r\n that a digital signature based on a private key was created while\r\n the corresponding public-key certificate was valid, i.e., before\r\n the certificate either expired or was revoked. Establishing this\r\n proof would enable the certificate to be used after its expiration\r\n or revocation, to verify a signature that was created earlier.\r\n This kind of proof is required as part of implementing PKI\r\n services, such as non-repudiation service, and long-term security\r\n services, such as audit.\r\n $ Time-Stamp Protocol\r\n (I) An Internet protocol (RFC 3161) that specifies how a client\r\n requests and receives a time stamp from a server for a data object\r\n held by the client.\r\n Tutorial: The protocol describes the format of (a) a request sent\r\n to a time-stamp authority and (b) the response that is returned\r\n containing a time stamp. The authority creates the stamp by\r\nShirey Informational [Page 307]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 366 of 436\n\nconcatenating (a) a hash value of the input data object with (b) a\r\n UTC time value and other parameters (policy OID, serial number,\r\n indication of time accuracy, nonce, DN of the authority, and\r\n various extensions), and then signing that dataset with the\r\n authority's private key as specified in CMS. Such an authority\r\n typically would operate as a trusted third-party service, but\r\n other operational models might be used.\r\n $ timing channel\r\n (I) See: covert timing channel.\r\n $ TKEY\r\n (I) A mnemonic referring to an Internet protocol (RFC 2930) for\r\n establishing a shared secret key between a DNS resolver and a DNS\r\n name server. (See: TSIG.)\r\n $ TLS\r\n (I) See: Transport Layer Security.\r\n $ TLSP\r\n (N) See: Transport Layer Security Protocol.\r\n $ TOE\r\n (N) See: target of evaluation.\r\n $ token\r\n 1. (I) /cryptography/ See: cryptographic token. (Compare: dongle.)\r\n 2. (I) /access control/ An object that is used to control access\r\n and is passed between cooperating entities in a protocol that\r\n synchronizes use of a shared resource. Usually, the entity that\r\n currently holds the token has exclusive access to the resource.\r\n (See: capability token.)\r\n Usage: This term is heavily overloaded in the computing\r\n literature; therefore, IDOCs SHOULD NOT use this term with any\r\n definition other than 1 or 2.\r\n 3a. (D) /authentication/ A data object or a physical device used\r\n to verify an identity in an authentication process.\r\n 3b. (D) /U.S. Government/ Something that the claimant in an\r\n authentication process (i.e., the entity that claims an identity)\r\n possesses and controls, and uses to prove the claim during the\r\n verification step of the process. [SP63]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 367 of 436\n\nDeprecated usage: IDOCs SHOULD NOT use this term with definitions\r\n 3a and 3b; instead, use more specifically descriptive and\r\nShirey Informational [Page 308]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n informative terms such as \"authentication information\" or\r\n \"cryptographic token\", depending on what is meant.\r\n NIST defines four types of claimant tokens for electronic\r\n authentication in an information system [SP63]. IDOCs SHOULD NOT\r\n use these four NIST terms; they mix concepts in potentially\r\n confusing ways and duplicate the meaning of better-established\r\n terms. These four terms can be avoided by using more specifically\r\n descriptive terms as follows:\r\n - NIST \"hard token\": A hardware device that contains a protected\r\n cryptographic key. (This is a type of \"cryptographic token\",\r\n and the key is a type of \"authentication information\".)\r\n - NIST \"one-time password device token\": A personal hardware\r\n device that generates one-time passwords. (One-time passwords\r\n are typically generated cryptographically. Therefore, this is a\r\n type of \"cryptographic token\", and the key is a type of\r\n \"authentication information\".)\r\n - NIST \"soft token\": A cryptographic key that typically is stored\r\n on disk or some other magnetic media. (The key is a type of\r\n \"authentication information\"; \"authentication key\" would be a\r\n better description.)\r\n - NIST \"password token\": A secret data value that the claimant\r\n memorizes. (This is a \"password\" that is being used as\r\n \"authentication information\".)\r\n $ token backup\r\n (I) A token management operation that stores sufficient\r\n information in a database (e.g., in a CAW) to recreate or restore\r\n a security token (e.g., a smart card) if it is lost or damaged.\r\n $ token copy\r\n (I) A token management operation that copies all the personality\r\n information from one security token to another. However, unlike in\r\n a token restore operation, the second token is initialized with\r\n its own, different local security values such as PINs and storage\r\n keys.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 368 of 436\n\n$ token management\r\n (I) The process that includes initializing security tokens (e.g.,\r\n \"smart card\"), loading data into the tokens, and controlling the\r\n tokens during their lifecycle. May include performing key\r\n management and certificate management functions; generating and\r\n installing PINs; loading user personality data; performing card\r\n backup, card copy, and card restore operations; and updating\r\n firmware.\r\nShirey Informational [Page 309]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ token restore\r\n (I) A token management operation that loads a security token with\r\n data for the purpose of recreating (duplicating) the contents\r\n previously held by that or another token. (See: recovery.)\r\n $ token storage key\r\n (I) A cryptographic key used to protect data that is stored on a\r\n security token.\r\n $ top CA\r\n (I) Synonym for \"root\" in a certification hierarchy. (See: apex\r\n trust anchor.)\r\n $ top-level specification\r\n (I) \"A non-procedural description of system behavior at the most\r\n abstract level; typically a functional specification that omits\r\n all implementation details.\" [NCS04] (See: formal top-level\r\n specification, Tutorial under \"security policy\".)\r\n Tutorial: A top-level specification is at a level of abstraction\r\n below \"security model\" and above \"security architecture\" (see:\r\n Tutorial under \"security policy\").\r\n A top-level specification may be descriptive or formal:\r\n - \"Descriptive top-level specification\": One that is written in a\r\n natural language like English or an informal design notation.\r\n - \"Formal top-level specification\": One that is written in a\r\n formal mathematical language to enable theorems to be proven\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 369 of 436\n\nthat show that the specification correctly implements a set of\r\n formal requirements or a formal security model. (See:\r\n correctness proof.)\r\n $ TPM\r\n (N) See: Trusted Platform Module.\r\n $ traceback\r\n (I) Identification of the source of a data packet. (See:\r\n masquerade, network weaving.)\r\n $ tracker\r\n (N) An attack technique for achieving unauthorized disclosure from\r\n a statistical database. [Denns] (See: Tutorial under \"inference\r\n control\".)\r\n $ traffic analysis\r\n 1. (I) Gaining knowledge of information by inference from\r\n observable characteristics of a data flow, even if the information\r\n is not directly available (e.g., when the data is encrypted).\r\nShirey Informational [Page 310]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n These characteristics include the identities and locations of the\r\n source(s) and destination(s) of the flow, and the flow's presence,\r\n amount, frequency, and duration of occurrence. The object of the\r\n analysis might be information in SDUs, information in the PCI, or\r\n both. (See: inference, traffic-flow confidentiality, wiretapping.\r\n Compare: signal analysis.)\r\n 2. (O) \"The inference of information from observation of traffic\r\n flows (presence, absence, amount, direction, and frequency).\"\r\n [I7498-2]\r\n $ traffic-flow analysis\r\n (I) Synonym for \"traffic analysis\".\r\n $ traffic-flow confidentiality (TFC)\r\n 1. (I) A data confidentiality service to protect against traffic\r\n analysis. (See: communications cover.)\r\n 2. (O) \"A confidentiality service to protect against traffic\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 370 of 436\n\nanalysis.\" [I7498-2]\r\n Tutorial: Confidentiality concerns involve both direct and\r\n indirect disclosure of data, and the latter includes traffic\r\n analysis. However, operational considerations can make TFC\r\n difficult to achieve. For example, if Alice sends a product idea\r\n to Bob in an email message, she wants data confidentiality for the\r\n message's content, and she might also want to conceal the\r\n destination of the message to hide Bob's identity from her\r\n competitors. However, the identity of the intended recipient, or\r\n at least a network address for that recipient, needs to be made\r\n available to the mail system. Thus, complex forwarding schemes may\r\n be needed to conceal the ultimate destination as the message\r\n travels through the open Internet (see: onion routing).\r\n Later, if Alice uses an ATM during a clandestine visit to\r\n negotiate with Bob, she might prefer that her bank conceal the\r\n origin of her transaction, because knowledge of the ATM's location\r\n might allow a competitor to infer Bob's identity. The bank, on the\r\n other hand, might prefer to protect only Alice's PIN (see:\r\n selective-field confidentiality).\r\n A TFC service can be either full or partial:\r\n - \"Full TFC\": This type of service conceals all traffic\r\n characteristics.\r\n - \"Partial TFC\": This type of service either (a) conceals some\r\n but not all of the characteristics or (b) does not completely\r\n conceal some characteristic.\r\nShirey Informational [Page 311]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n On point-to-point data links, full TFC can be provided by\r\n enciphering all PDUs and also generating a continuous, random data\r\n stream to seamlessly fill all gaps between PDUs. To a wiretapper,\r\n the link then appears to be carrying an unbroken stream of\r\n enciphered data. In other cases -- including on a shared or\r\n broadcast medium, or end-to-end in a network -- only partial TFC\r\n is possible, and that may require a combination of techniques. For\r\n example, a LAN that uses \"carrier sense multiple access with\r\n collision detection\" (CSMA/CD; a.k.a. \"listen while talk\") to\r\n control access to the medium, relies on detecting intervals of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 371 of 436\n\nsilence, which prevents using full TFC. Partial TFC can be\r\n provided on that LAN by measures such as adding spurious PDUs,\r\n padding PDUs to a constant size, or enciphering addresses just\r\n above the Physical Layer; but these measures reduce the efficiency\r\n with which the LAN can carry traffic. At higher protocol layers,\r\n SDUs can be protected, but addresses and other items of PCI must\r\n be visible at the layers below.\r\n $ traffic key\r\n (I) A cryptographic key used by a device for protecting\r\n information that is being transmitted between devices, as opposed\r\n to protecting information that being is maintained in the device.\r\n (Compare: storage key.)\r\n $ traffic padding\r\n (I) \"The generation of spurious instances of communication,\r\n spurious data units, and/or spurious data within data units.\"\r\n [I7498-2]\r\n $ tranquility property\r\n (N) /formal model/ Property of a system whereby the security level\r\n of an object cannot change while the object is being processed by\r\n the system. (See: Bell-LaPadula model.)\r\n $ transaction\r\n 1. (I) A unit of interaction between an external entity and a\r\n system, or between components within a system, that involves a\r\n series of system actions or events.\r\n 2. (O) \"A discrete event between user and systems that supports a\r\n business or programmatic purpose.\" [M0404]\r\n Tutorial: To maintain secure state, transactions need to be\r\n processed coherently and reliably. Usually, they need to be\r\n designed to be atomic, consistent, isolated, and durable [Gray]:\r\n - \"Atomic\": All actions and events that comprise the transaction\r\n are guaranteed to be completed successfully, or else the result\r\n is as if none at all were executed.\r\nShirey Informational [Page 312]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - \"Consistent\": The transaction satisfies correctness constraints\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 372 of 436\n\ndefined for the data that is being processed.\r\n - \"Isolated\": If two transactions are performed concurrently,\r\n they do not interfere with each other, and it appears as though\r\n the system performs one at a time.\r\n - \"Durable\": System state and transaction semantics survive\r\n system failures.\r\n $ TRANSEC\r\n (I) See: transmission security.\r\n $ Transmission Control Code field (TCC field)\r\n (I) A data field that provides a means to segregate traffic and\r\n define controlled communities of interest in the security option\r\n (option type = 130) of IPv4's datagram header format. The TCC\r\n values are alphanumeric trigraphs assigned by the U.S. Government\r\n as specified in RFC 791.\r\n $ Transmission Control Protocol (TCP)\r\n (I) An Internet Standard, Transport-Layer protocol (RFC 793) that\r\n reliably delivers a sequence of datagrams from one computer to\r\n another in a computer network. (See: TCP/IP.)\r\n Tutorial: TCP is designed to fit into a layered suite of protocols\r\n that support internetwork applications. TCP assumes it can obtain\r\n a simple but potentially unreliable end-to-end datagram service\r\n (such as IP) from the lower-layer protocols.\r\n $ transmission security (TRANSEC)\r\n (I) COMSEC measures that protect communications from interception\r\n and exploitation by means other than cryptanalysis. Example:\r\n frequency hopping. (Compare: anti-jam, traffic flow\r\n confidentiality.)\r\n $ Transport Layer\r\n See: Internet Protocol Suite, OSIRM.\r\n $ Transport Layer Security (TLS)\r\n (I) TLS is an Internet protocol [R4346] that is based on, and very\r\n similar to, SSL Version 3.0. (Compare: TLSP.)\r\n Tutorial: The TLS protocol is misnamed. The name misleadingly\r\n suggests that TLS is situated in the IPS Transport Layer, but TLS\r\n is always layered above a reliable Transport-Layer protocol\r\n (usually TCP) and either layered immediately below or integrated\r\n with an Application-Layer protocol (often HTTP).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 373 of 436\n\nShirey Informational [Page 313]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Transport Layer Security Protocol (TLSP)\r\n (N) An end-to-end encryption protocol (ISO 10736) that provides\r\n security services at the bottom of OSIRM Layer 4, i.e., directly\r\n above Layer 3. (Compare: TLS.)\r\n Tutorial: TLSP evolved directly from SP4.\r\n $ transport mode\r\n (I) One of two ways to apply AH or ESP to protect data packets; in\r\n this mode, the IPsec protocol encapsulates (i.e., the protection\r\n applies to) the packets of an IPS Transport-Layer protocol (e.g.,\r\n TCP, UDP), which normally is carried directly above IP in an IPS\r\n protocol stack. (Compare: tunnel mode.)\r\n Tutorial: An IPsec transport-mode security association is always\r\n between two hosts; neither end has the role of a security gateway.\r\n Whenever either end of an IPsec security association is a security\r\n gateway, the association is required to be in tunnel mode.\r\n $ transposition\r\n (I) /cryptography/ A method of encryption in which elements of the\r\n plain text retain their original form but undergo some change in\r\n their sequential position. (Compare: substitution.)\r\n $ trap door\r\n (I) Synonym for \"back door\".\r\n $ trespass\r\n (I) /threat action/ See: secondary definition under \"intrusion\".\r\n $ Triple Data Encryption Algorithm\r\n (I) A block cipher that transforms each 64-bit plaintext block by\r\n applying the DEA three successive times, using either two or three\r\n different keys for an effective key length of 112 or 168 bits.\r\n [A9052, SP67]\r\n Example: A variation proposed for IPsec's ESP uses a 168-bit key,\r\n consisting of three independent 56-bit values used by the DEA, and\r\n a 64-bit initialization vector. Each datagram contains an IV to\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 374 of 436\n\nensure that each received datagram can be decrypted even when\r\n other datagrams are dropped or a sequence of datagrams is\r\n reordered in transit. [R1851]\r\n $ triple-wrapped\r\n (I) /S-MIME/ Data that has been signed with a digital signature,\r\n then encrypted, and then signed again. [R2634]\r\nShirey Informational [Page 314]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Trojan horse\r\n (I) A computer program that appears to have a useful function, but\r\n also has a hidden and potentially malicious function that evades\r\n security mechanisms, sometimes by exploiting legitimate\r\n authorizations of a system entity that invokes the program. (See:\r\n malware, spyware. Compare: logic bomb, virus, worm.)\r\n $ trust\r\n 1. (I) /information system/ A feeling of certainty (sometimes\r\n based on inconclusive evidence) either (a) that the system will\r\n not fail or (b) that the system meets its specifications (i.e.,\r\n the system does what it claims to do and does not perform unwanted\r\n functions). (See: trust level, trusted system, trustworthy system.\r\n Compare: assurance.)\r\n Tutorial: Components of a system can be grouped into three classes\r\n of trust [Gass]:\r\n - \"Trusted\": The component is responsible for enforcing security\r\n policy on other components; the system's security depends on\r\n flawless operation of the component. (See: trusted process.)\r\n - \"Benign\": The component is not responsible for enforcing\r\n security policy, but it has sensitive authorizations. It must\r\n be trusted not to intentionally violate security policy, but\r\n security violations are assumed to be accidental and not likely\r\n to affect overall system security.\r\n - \"Untrusted\": The component is of unknown or suspicious\r\n provenance and must be treated as deliberately malicious. (See:\r\n malicious logic.)\r\n 2. (I) /PKI/ A relationship between a certificate user and a CA in\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 375 of 436\n\nwhich the user acts according to the assumption that the CA\r\n creates only valid digital certificates.\r\n Tutorial: \"Generally, an entity is said to 'trust' a second entity\r\n when the first entity makes the assumption that the second entity\r\n will behave exactly as the first entity expects. This trust may\r\n apply only for some specific function. The key role of trust in\r\n [X.509] is to describe the relationship between an entity [i.e., a\r\n certificate user] and a [CA]; an entity shall be certain that it\r\n can trust the CA to create only valid and reliable certificates.\"\r\n [X509]\r\n $ trust anchor\r\n (I) /PKI/ An established point of trust (usually based on the\r\n authority of some person, office, or organization) from which a\r\n certificate user begins the validation of a certification path.\r\n (See: apex trust anchor, path validation, trust anchor CA, trust\r\n anchor certificate, trust anchor key.)\r\nShirey Informational [Page 315]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because it is used in various ways in existing IDOCs and other PKI\r\n literature. The literature almost always uses this term in a sense\r\n that is equivalent to this definition, but usage often differs\r\n with regard to what constitutes the point of trust.\r\n Tutorial: A trust anchor may be defined as being based on a public\r\n key, a CA, a public-key certificate, or some combination or\r\n variation of those:\r\n - 1. A public key as a point of trust: Although a certification\r\n path is defined as beginning with a \"sequence of public-key\r\n certificates\", an implementation of a path validation process\r\n might not explicitly handle a root certificate as part of the\r\n path, but instead begin the process by using a trusted root key\r\n to verify the signature on a certificate that was issued by the\r\n root.\r\n Therefore, \"trust anchor\" is sometimes defined as just a public\r\n key. (See: root key, trust anchor key, trusted key.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 376 of 436\n\n- 2. A CA as a point of trust: A trusted public key is just one\r\n of the data elements needed for path validation; the IPS path\r\n validation algorithm [R3280] also needs the name of the CA to\r\n which that key belongs, i.e., the DN of the issuer of the first\r\n X.509 certificate to be validated on the path. (See: issue.)\r\n Therefore, \"trust anchor\" is sometimes defined as either just a\r\n CA (where some public key is implied) or as a CA together with\r\n a specified public key belonging to that CA. (See: root, trust\r\n anchor CA, trusted CA.)\r\n Example: \"A public key and the name of a [CA] that is used to\r\n validate the first certificate in a sequence of certificates.\r\n The trust anchor public key is used to verify the signature on\r\n a certificate issued by a trust anchor [CA].\" [SP57]\r\n - 3. A public-key certificate as a point of trust: Besides the\r\n trusted CA's public key and name, the path validation algorithm\r\n needs to know the digital signature algorithm and any\r\n associated parameters with which the public key is used, and\r\n also any constraints that have been placed on the set of paths\r\n that may be validated using the key. All of this information is\r\n available from a CA's public-key certificate.\r\n Therefore, \"trust anchor\" is sometimes defined as a public-key\r\n certificate of a CA. (See: root certificate, trust anchor\r\n certificate, trusted certificate.)\r\nShirey Informational [Page 316]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - 4. Combinations: Combinations and variations of the first three\r\n definitions are also used in the PKI literature.\r\n Example: \"trust anchor information\". The IPS standard for path\r\n validation [R3280] specifies the information that describes \"a\r\n CA that serves as a trust anchor for the certification path.\r\n The trust anchor information includes: (a) the trusted issuer\r\n name, (b) the trusted public key algorithm, (c) the trusted\r\n public key, and (d) optionally, the trusted public key\r\n parameters associated with the public key. The trust anchor\r\n information may be provided to the path processing procedure in\r\n the form of a self-signed certificate. The trusted anchor\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 377 of 436\n\ninformation is trusted because it was delivered to the path\r\n processing procedure by some trustworthy out-of-band procedure.\r\n If the trusted public key algorithm requires parameters, then\r\n the parameters are provided along with the trusted public key.\"\r\n $ trust anchor CA\r\n (I) A CA that is the subject of a trust anchor certificate or\r\n otherwise establishes a trust anchor key. (See: root, trusted CA.)\r\n Tutorial: The selection of a CA to be a trust anchor is a matter\r\n of policy. Some of the possible choices include (a) the top CA in\r\n a hierarchical PKI, (b) the CA that issued the verifier's own\r\n certificate, or (c) any other CA in a network PKI. Different\r\n applications may rely on different trust anchors, or may accept\r\n paths that begin with any of a set of trust anchors. The IPS path\r\n validation algorithm is the same, regardless of the choice.\r\n $ trust anchor certificate\r\n (I) A public-key certificate that is used to provide the first\r\n public key in a certification path. (See: root certificate, trust\r\n anchor, trusted certificate.)\r\n $ trust anchor key\r\n (I) A public key that is used as the first public key in a\r\n certification path. (See: root key, trust anchor, trusted public\r\n key.)\r\n $ trust anchor information\r\n (I) See: secondary definition under \"trust anchor\".\r\n $ trust chain\r\n (D) Synonym for \"certification path\". (See: trust anchor, trusted\r\n certificate.)\r\nShirey Informational [Page 317]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term, because it\r\n unnecessarily duplicates the meaning of the internationally\r\n standardized term.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 378 of 436\n\nAlso, the term mixes concepts in a potentially misleading way.\r\n Having \"trust\" involves factors unrelated to simply verifying\r\n signatures and performing other tests as specified by a standard\r\n algorithm for path validation (e.g., RFC 3280). Thus, even if a\r\n user is able to validate a certification path algorithmically, the\r\n user still might distrust one of the CAs that issued certificates\r\n in that path or distrust some other aspects of the PKI.\r\n $ trust-file PKI\r\n (I) A non-hierarchical PKI in which each certificate user has its\r\n own local file (which is used by application software) of trust\r\n anchors, i.e., either public keys or public-key certificates that\r\n the user trusts as starting points for certification paths. (See:\r\n trust anchor, web of trust. Compare: hierarchical PKI, mesh PKI.)\r\n Example: Popular browsers are distributed with an initial file of\r\n trust anchor certificates, which often are self-signed\r\n certificates. Users can add certificates to the file or delete\r\n from it. The file may be directly managed by the user, or the\r\n user's organization may manage it from a centralized server.\r\n $ trust hierarchy\r\n (D) Synonym for \"certification hierarchy\".\r\n Deprecated Usage: IDOCs SHOULD NOT use this term because it mixes\r\n concepts in a potentially misleading way, and because a trust\r\n hierarchy could be implemented in other ways. (See: trust, trust\r\n chain, web of trust.)\r\n $ trust level\r\n (N) A characterization of a standard of security protection to be\r\n met by an information system. (See: Common Criteria, TCSEC.)\r\n Tutorial: A trust level is based not only on (a) the presence of\r\n security mechanisms, but also on the use of (b) systems\r\n engineering discipline to properly structure the system and (c)\r\n implementation analysis to ensure that the system provides an\r\n appropriate degree of trust.\r\n $ trusted\r\n (I) See: secondary definition under \"trust\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 379 of 436\n\nShirey Informational [Page 318]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ trusted CA\r\n (I) A CA upon which a certificate user relies as issuing valid\r\n certificates; especially a CA that is used as a trust anchor CA.\r\n (See: certification path, root, trust anchor CA, validation.)\r\n Tutorial. This trust is transitive to the extent that the X.509\r\n certificate extensions permit; that is, if a trusted CA issues a\r\n certificate to another CA, a user that trusts the first CA also\r\n trusts the second CA if the user succeeds in validating the\r\n certificate path (see: path validation).\r\n $ trusted certificate\r\n (I) A digital certificate that a certificate user accepts as being\r\n valid \"a priori\", i.e., without testing the certificate to\r\n validate it as the final certificate on a certification path;\r\n especially a certificate that is used as a trust anchor\r\n certificate. (See: certification path, root certificate, trust\r\n anchor certificate, trust-file PKI, validation.)\r\n Tutorial: The acceptance of a certificate as trusted is a matter\r\n of policy and choice. Usually, a certificate is accepted as\r\n trusted because the user obtained it by reliable, out-of-band\r\n means that cause the user to believe the certificate accurately\r\n binds its subject's name to the subject's public key or other\r\n attribute values. Many choices are possible; e.g., a trusted\r\n public-key certificate might be (a) the root certificate in a\r\n hierarchical PKI, (b) the certificate of the CA that issued the\r\n user's own certificate in a mesh PKI, or (c) a certificate\r\n provided with an application that uses a trust-file PKI.\r\n $ Trusted Computer System Evaluation Criteria (TCSEC)\r\n (N) A standard for evaluating the security provided by operating\r\n systems [CSC1, DoD1]. Known as the \"Orange Book\" because of the\r\n color of its cover; first document in the Rainbow Series. (See:\r\n Common Criteria, Deprecated Usage under \"Green Book\", Orange Book,\r\n trust level, trusted system. Compare: TSEC.)\r\n Tutorial: The TCSEC defines classes of hierarchically ordered\r\n assurance levels for rating computer systems. From highest to\r\n lowest, the classes are as follows:\r\n - Division A: Verified protection.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 380 of 436\n\nBeyond A1 Beyond current technology. (See: beyond A1.)\r\n Class A1 Verified design. (See: SCOMP.)\r\n - Division B: Mandatory protection.\r\n Class B3 Security domains.\r\n Class B2 Structured protection. (See: Multics.)\r\n Class B1 Labeled security protection.\r\nShirey Informational [Page 319]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n - Division C: Discretionary protection.\r\n Class C2 Controlled access protection.\r\n Class C1 Discretionary security protection.\r\n - Division D: Minimal protection, i.e., has been evaluated but\r\n does not meet the requirements for a higher evaluation class.\r\n $ trusted computing base (TCB)\r\n (N) \"The totality of protection mechanisms within a computer\r\n system, including hardware, firmware, and software, the\r\n combination of which is responsible for enforcing a security\r\n policy.\" [NCS04] (See: \"trusted\" under \"trust\". Compare: TPM.)\r\n $ Trusted Computing Group (TCG)\r\n (N) A not-for-profit, industry standards organization formed to\r\n develop, define, and promote open standards for hardware-enabled\r\n trusted computing and security technologies, including hardware\r\n building blocks and software interfaces, across multiple\r\n platforms, peripherals, and devices. (See: TPM, trusted system.\r\n Compare: TSIG.)\r\n $ trusted distribution\r\n (I) /COMPUSEC/ \"A trusted method for distributing the TCB\r\n hardware, software, and firmware components, both originals and\r\n updates, that provides methods for protecting the TCB from\r\n modification during distribution and for detection of any changes\r\n to the TCB that may occur.\" [NCS04] (See: code signing,\r\n configuration control.)\r\n $ trusted key\r\n (D) Abbreviation for \"trusted public key\" and also for other types\r\n of keys. (See: root key, trust anchor key.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 381 of 436\n\nDeprecated Usage: IDOCs SHOULD either (a) state a definition for\r\n this term or (b) use a different, less ambiguous term. This term\r\n is ambiguous when it stands alone; e.g., it could refer to a\r\n trusted public key or to a private key or symmetric key that is\r\n believed to be secure (i.e., not compromised).\r\n $ trusted path\r\n 1a. (I) /COMPUSEC/ A mechanism by which a computer system user can\r\n communicate directly and reliably with the TCB and that can only\r\n be activated by the user or the TCB and cannot be imitated by\r\n untrusted software within the computer. [NCS04]\r\n 1b. (I) /COMSEC/ A mechanism by which a person or process can\r\n communicate directly with a cryptographic module and that can only\r\n be activated by the person, process, or module, and cannot be\r\n imitated by untrusted software within the module. [FP140]\r\nShirey Informational [Page 320]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Trusted Platform Module (TPM)\r\n (N) The name of a specification, published by the TCG, for a\r\n microcontroller that can store secured information; and also the\r\n general name of implementations of that specification. (Compare:\r\n TCB.)\r\n $ trusted process\r\n (I) A system component that has privileges that enable it to\r\n affect the state of system security and that can, therefore,\r\n through incorrect or malicious execution, violate the system's\r\n security policy. (See: privileged process, trusted system.)\r\n $ trusted public key\r\n (I) A public key upon which a user relies; especially a public key\r\n that is used as a trust anchor key. (See: certification path, root\r\n key, trust anchor key, validation.)\r\n Tutorial: A trusted public key could be (a) the root key in a\r\n hierarchical PKI, (b) the key of the CA that issued the user's own\r\n certificate in a mesh PKI, or (c) any key accepted by the user in\r\n a trust-file PKI.\r\n $ trusted recovery\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 382 of 436\n\n(I) A process that, after a system has experienced a failure or an\r\n attack, restores the system to normal operation (or to a secure\r\n state) without causing a security compromise. (See: recovery.)\r\n $ trusted subnetwork\r\n (I) A subnetwork containing hosts and routers that trust each\r\n other not to engage in active or passive attacks. (There also is\r\n an assumption that the underlying communication channels, such as\r\n telephone lines or a LAN, are protected from attack.)\r\n $ trusted system\r\n 1. (I) /information system/ A system that operates as expected,\r\n according to design and policy, doing what is required -- despite\r\n environmental disruption, human user and operator errors, and\r\n attacks by hostile parties -- and not doing other things [NRC98].\r\n (See: trust level, trusted process. Compare: trustworthy.)\r\n 2. (N) /multilevel secure/ \"A [trusted system is a] system that\r\n employs sufficient hardware and software assurance measures to\r\n allow its use for simultaneous processing of a range of sensitive\r\n or classified information.\" [NCS04] (See: multilevel security\r\n mode.)\r\nShirey Informational [Page 321]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ Trusted Systems Interoperability Group (TSIG)\r\n (N) A forum of computer vendors, system integrators, and users\r\n devoted to promoting interoperability of trusted computer systems.\r\n (See: trusted system. Compare: TCG.)\r\n $ trustworthy system\r\n 1. (I) A system that not only is trusted, but also warrants that\r\n trust because the system's behavior can be validated in some\r\n convincing way, such as through formal analysis or code review.\r\n (See: trust. Compare: trusted.)\r\n 2. (O) /Digital Signature Guidelines/ \"Computer hardware,\r\n software, and procedures that: (a) are reasonably secure from\r\n intrusion and misuse; (b) provide a reasonably reliable level of\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 383 of 436\n\navailability, reliability, and correct operation; (c) are\r\n reasonably suited to performing their intended functions; and (d)\r\n adhere to generally accepted security principles.\" [DSG]\r\n $ TSEC\r\n (O) See: Telecommunications Security Nomenclature System.\r\n (Compare: TCSEC.)\r\n $ TSIG\r\n 1. (N) See: Trusted System Interoperability Group.\r\n 2. (I) A mnemonic (presumed to be derived from \"Transaction\r\n SIGnature\") referring to an Internet protocol (RFC 2845) for data\r\n origin authentication and data integrity for certain DNS\r\n operations. (See: TKEY.)\r\n $ tunnel\r\n 1. (I) A communication channel created in a computer network by\r\n encapsulating (i.e., layering) a communication protocol's data\r\n packets in (i.e., above) a second protocol that normally would be\r\n carried above, or at the same layer as, the first one. (See: L2TP,\r\n tunnel mode, VPN. Compare: covert channel.)\r\n Tutorial: Tunneling can involve almost any two IPS protocol\r\n layers. For example, a TCP connection between two hosts could\r\n conceivably be carried above SMTP (i.e., in SMTP messages) as a\r\n covert channel to evade access controls that a security gateway\r\n applies to the normal TCP layer that is below SMTP.\r\n Usually, however, a tunnel is a logical point-to-point link --\r\n i.e., an OSIRM Layer 2 connection -- created by encapsulating the\r\n Layer 2 protocol in one of the following three types of IPS\r\n protocols: (a) an IPS Transport-Layer protocol (such as TCP), (b)\r\n an IPS Network-Layer or Internet-Layer protocol (such as IP), or\r\nShirey Informational [Page 322]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n (c) another Layer 2 protocol. In many cases, the encapsulation is\r\n accomplished with an extra, intermediate protocol (i.e., a\r\n \"tunneling protocol\"; e.g., L2TP) that is layered below the\r\n tunneled Layer 2 protocol and above the encapsulating protocol.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 384 of 436\n\nTunneling can be used to move data between computers that use a\r\n protocol not supported by the network connecting them. Tunneling\r\n also can enable a computer network to use the services of a second\r\n network as though the second network were a set of point-to-point\r\n links between the first network's nodes. (See: VPN.)\r\n 2. (O) /SET/ The name of a SET private extension that indicates\r\n whether the CA or the payment gateway supports passing encrypted\r\n messages to the cardholder through the merchant. If so, the\r\n extension lists OIDs of symmetric encryption algorithms that are\r\n supported.\r\n $ tunnel mode\r\n (I) One of two ways to apply the IPsec protocols (AH and ESP) to\r\n protect data packets; in this mode, the IPsec protocol\r\n encapsulates (i.e., the protection applies to) IP packets, rather\r\n than the packets of higher-layer protocols. (See: tunnel. Compare:\r\n transport mode.)\r\n Tutorial: Each end of a tunnel-mode security association may be\r\n either a host or a security gateway. Whenever either end of an\r\n IPsec security association is a security gateway, the association\r\n is required to be in tunnel mode.\r\n $ two-person control\r\n (I) The close surveillance and control of a system, a process, or\r\n materials (especially with regard to cryptography) at all times by\r\n a minimum of two appropriately authorized persons, each capable of\r\n detecting incorrect and unauthorized procedures with respect to\r\n the tasks to be performed and each familiar with established\r\n security requirements. (See: dual control, no-lone zone.)\r\n $ Twofish\r\n (O) A symmetric, 128-bit block cipher with variable key length\r\n (128, 192, or 256 bits), developed by Counterpane Labs as a\r\n candidate for the AES. (See: Blowfish.)\r\n $ type 0 product\r\n (O) /cryptography, U.S. Government/ Classified cryptographic\r\n equipment endorsed by NSA for use (when appropriately keyed) in\r\n electronically distributing bulk keying material.\r\nShirey Informational [Page 323]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 385 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ type 1 key\r\n (O) /cryptography, U.S. Government/ \"Generated and distributed\r\n under the auspices of NSA for use in a cryptographic device for\r\n the protection of classified and sensitive national security\r\n information.\" [C4009]\r\n $ type 1 product\r\n (O) /cryptography, U.S. Government/ \"Cryptographic equipment,\r\n assembly or component classified or certified by NSA for\r\n encrypting and decrypting classified and sensitive national\r\n security information when appropriately keyed. Developed using\r\n established NSA business processes and containing NSA approved\r\n algorithms. Used to protect systems requiring the most stringent\r\n protection mechanisms.\" [C4009]\r\n Tutorial: The current definition of this term is less specific\r\n than an earlier version: \"Classified or controlled cryptographic\r\n item endorsed by the NSA for securing classified and sensitive\r\n U.S. Government information, when appropriately keyed. The term\r\n refers only to products, and not to information, key, services, or\r\n controls. Type 1 products contain classified NSA algorithms. They\r\n are available to U.S. Government users, their contractors, and\r\n federally sponsored non-U.S. Government activities subject to\r\n export restrictions in accordance with International Traffic in\r\n Arms Regulation.\" [from an earlier version of C4009] (See: ITAR.)\r\n $ type 2 key\r\n (O) /cryptography, U.S. Government/ \"Generated and distributed\r\n under the auspices of NSA for use in a cryptographic device for\r\n the protection of unclassified national security information.\"\r\n [C4009]\r\n $ type 2 product\r\n (O) /cryptography, U.S. Government/ \"Cryptographic equipment,\r\n assembly, or component certified by NSA for encrypting or\r\n decrypting sensitive national security information when\r\n appropriately keyed. Developed using established NSA business\r\n processes and containing NSA approved algorithms. Used to protect\r\n systems requiring protection mechanisms exceeding best commercial\r\n practices including systems used for the protection of\r\n unclassified national security information.\" [C4009]\r\n Tutorial: The current definition of this term is less specific\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 386 of 436\n\nthan an earlier version: \"Unclassified cryptographic equipment,\r\n assembly, or component, endorsed by the NSA, for use in national\r\n security systems as defined in Title 40 U.S.C. Section 1452.\"\r\n [from an earlier version of C4009] (See: national security system.\r\n Compare: EUCI.)\r\nShirey Informational [Page 324]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ type 3 key\r\n (O) /cryptography, U.S. Government/ \"Used in a cryptographic\r\n device for the protection of unclassified sensitive information,\r\n even if used in a Type 1 or Type 2 product.\" [C4009]\r\n $ type 3 product\r\n (O) /cryptography, U.S. Government/ \"Unclassified cryptographic\r\n equipment, assembly, or component used, when appropriately keyed,\r\n for encrypting or decrypting unclassified sensitive U.S.\r\n Government or commercial information, and to protect systems\r\n requiring protection mechanisms consistent with standard\r\n commercial practices. Developed using established commercial\r\n standards and containing NIST approved cryptographic\r\n algorithms/modules or successfully evaluated by the National\r\n Information Assurance Partnership (NIAP).\" [C4009]\r\n $ type 4 key\r\n (O) /cryptography, U.S. Government/ \"Used by a cryptographic\r\n device in support of its Type 4 functionality; i.e., any provision\r\n of key that lacks U.S. Government endorsement or oversight.\"\r\n [C4009]\r\n $ type 4 product\r\n (O) /cryptography, U.S. Government/ \"Unevaluated commercial\r\n cryptographic equipment, assemblies, or components that neither\r\n NSA nor NIST certify for any Government usage. These products are\r\n typically delivered as part of commercial offerings and are\r\n commensurate with the vendor's commercial practices. These\r\n products may contain either vendor proprietary algorithms,\r\n algorithms registered by NIST, or algorithms registered by NIST\r\n and published in a FIPS.\" [C4009]\r\n $ UDP\r\n (I) See: User Datagram Protocol.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 387 of 436\n\n$ UDP flood\r\n (I) A denial-of-service attack that takes advantage of (a) one\r\n system's UDP test function that generates a series of characters\r\n for each packet it receives and (b) another system's UPD test\r\n function that echoes any character it receives; the attack\r\n connects (a) to (b) to cause a nonstop flow of data between the\r\n two systems. (See: flooding.)\r\n $ unauthorized disclosure\r\n (I) A circumstance or event whereby an entity gains access to\r\n information for which the entity is not authorized.\r\nShirey Informational [Page 325]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Tutorial: This type of threat consequence can be caused by the\r\n following types of threat actions: exposure, interception,\r\n inference, and intrusion. Some methods of protecting against this\r\n consequence include access control, flow control, and inference\r\n control. (See: data confidentiality.)\r\n $ unauthorized user\r\n (I) /access control/ A system entity that accesses a system\r\n resource for which the entity has not received an authorization.\r\n (See: user. Compare: authorized user, insider, outsider.)\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the term is used in many ways and could easily be\r\n misunderstood.\r\n $ uncertainty\r\n (N) An information-theoretic measure (usually stated as a number\r\n of bits) of the minimum amount of plaintext information that needs\r\n to be recovered from cipher text to learn the entire plain text\r\n that was encrypted. [SP63] (See: entropy.)\r\n $ unclassified\r\n (I) Not classified. (Compare: FOUO.)\r\n $ unencrypted\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 388 of 436\n\n(I) Not encrypted.\r\n $ unforgeable\r\n (I) /cryptography/ The property of a cryptographic data structure\r\n (i.e., a data structure that is defined using one or more\r\n cryptographic functions, e.g., \"digital certificate\") that makes\r\n it computationally infeasible to construct (i.e., compute) an\r\n unauthorized but correct value of the structure without having\r\n knowledge of one of more keys.\r\n Tutorial: This definition is narrower than general English usage,\r\n where \"unforgeable\" means unable to be fraudulently created or\r\n duplicated. In that broader sense, anyone can forge a digital\r\n certificate containing any set of data items whatsoever by\r\n generating the to-be-signed certificate and signing it with any\r\n private key whatsoever. But for PKI purposes, the forged data\r\n structure is invalid if it is not signed with the true private key\r\n of the claimed issuer; thus, the forgery will be detected when a\r\n certificate user uses the true public key of the claimed issuer to\r\n verify the signature.\r\nShirey Informational [Page 326]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ uniform resource identifier (URI)\r\n (I) A type of formatted identifier (RFC 3986) that encapsulates\r\n the name of an Internet object, and labels it with an\r\n identification of the name space, thus producing a member of the\r\n universal set of names in registered name spaces and of addresses\r\n referring to registered protocols or name spaces.\r\n Example: HTML uses URIs to identify the target of hyperlinks.\r\n Usage: \"A URI can be classified as a locator (see: URL), a name\r\n (see: URN), or both. ... Instances of URIs from any given scheme\r\n may have the characteristics of names or locators or both, often\r\n depending on the persistence and care in the assignment of\r\n identifiers by the naming authority, rather than on any quality of\r\n the scheme.\" IDOCs SHOULD \"use the general term 'URI' rather than\r\n the more restrictive terms 'URL' and 'URN'.\" (RFC 3986)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 389 of 436\n\n$ uniform resource locator (URL)\r\n (I) A URI that describes the access method and location of an\r\n information resource object on the Internet. (See: Usage under\r\n \"URI\". Compare: URN.)\r\n Tutorial: The term URL \"refers to the subset of URIs that, besides\r\n identifying a resource, provide a means of locating the resource\r\n by describing its primary access mechanism (e.g., its network\r\n 'location').\" (RFC 3986)\r\n A URL provides explicit instructions on how to access the named\r\n object. For example,\r\n \"ftp://bbnarchive.bbn.com/foo/bar/picture/cambridge.zip\" is a URL.\r\n The part before the colon specifies the access scheme or protocol,\r\n and the part after the colon is interpreted according to that\r\n access method. Usually, two slashes after the colon indicate the\r\n host name of a server (written as a domain name). In an FTP or\r\n HTTP URL, the host name is followed by the path name of a file on\r\n the server. The last (optional) part of a URL may be either a\r\n fragment identifier that indicates a position in the file, or a\r\n query string.\r\n $ uniform resource name (URN)\r\n (I) A URI with the properties of a name. (See: Usage under \"URI\".\r\n Compare: URL.)\r\n Tutorial: The term URN \"has been used historically to refer to\r\n both URIs under the \"urn\" scheme (RFC 2141), which are required to\r\n remain globally unique and persistent even when the resource\r\n ceases to exist or becomes unavailable, and to any other URI with\r\n the properties of a name.\" (RFC 3986)\r\nShirey Informational [Page 327]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ untrusted\r\n (I) See: secondary definition under \"trust\".\r\n $ untrusted process\r\n 1. (I) A system component that is not able to affect the state of\r\n system security through incorrect or malicious operation. Example:\r\n A component that has its operations confined by a security kernel.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 390 of 436\n\n(See: trusted process.)\r\n 2. (I) A system component that (a) has not been evaluated or\r\n examined for adherence to a specified security policy and,\r\n therefore, (b) must be assumed to contain logic that might attempt\r\n to circumvent system security.\r\n $ UORA\r\n (O) See: user-PIN ORA.\r\n $ update\r\n See: \"certificate update\" and \"key update\".\r\n $ upgrade\r\n (I) /data security/ Increase the classification level of data\r\n without changing the information content of the data. (See:\r\n classify, downgrade, regrade.)\r\n $ URI\r\n (I) See: uniform resource identifier.\r\n $ URL\r\n (I) See: uniform resource locator.\r\n $ URN\r\n (I) See: uniform resource name.\r\n $ user\r\n See: system user.\r\n Usage: IDOCs that use this term SHOULD state a definition for it\r\n because the term is used in many ways and could easily be\r\n misunderstood.\r\n $ user authentication service\r\n (I) A security service that verifies the identity claimed by an\r\n entity that attempts to access the system. (See: authentication,\r\n user.)\r\nShirey Informational [Page 328]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 391 of 436\n\n$ User Datagram Protocol (UDP)\r\n (I) An Internet Standard, Transport-Layer protocol (RFC 768) that\r\n delivers a sequence of datagrams from one computer to another in a\r\n computer network. (See: UPD flood.)\r\n Tutorial: UDP assumes that IP is the underlying protocol. UDP\r\n enables application programs to send transaction-oriented data to\r\n other programs with minimal protocol mechanism. UDP does not\r\n provide reliable delivery, flow control, sequencing, or other end-\r\n to-end service guarantees that TCP does.\r\n $ user identifier\r\n (I) See: identifier.\r\n $ user identity\r\n (I) See: identity.\r\n $ user PIN\r\n (O) /MISSI/ One of two PINs that control access to the functions\r\n and stored data of a FORTEZZA PC card. Knowledge of the user PIN\r\n enables a card user to perform the FORTEZZA functions that are\r\n intended for use by an end user. (See: PIN. Compare: SSO PIN.)\r\n $ user-PIN ORA (UORA)\r\n (O) /MISSI/ A MISSI organizational RA that operates in a mode in\r\n which the ORA performs only the subset of card management\r\n functions that are possible with knowledge of the user PIN for a\r\n FORTEZZA PC card. (See: no-PIN ORA, SSO-PIN ORA.)\r\n $ usurpation\r\n (I) A circumstance or event that results in control of system\r\n services or functions by an unauthorized entity. This type of\r\n threat consequence can be caused by the following types of threat\r\n actions: misappropriation, misuse. (See: access control.)\r\n $ UTCTime\r\n (N) The ASN.1 data type \"UTCTime\" contains a calendar date\r\n (YYMMDD) and a time to a precision of either one minute (HHMM) or\r\n one second (HHMMSS), where the time is either (a) Coordinated\r\n Universal Time or (b) the local time followed by an offset that\r\n enables Coordinated Universal Time to be calculated. (See:\r\n Coordinated Universal Time. Compare: GeneralizedTime.)\r\n Usage: If you care about centuries or millennia, you probably need\r\n to use the GeneralizedTime data type instead of UTCTime.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 392 of 436\n\nShirey Informational [Page 329]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ v1 certificate\r\n (N) An abbreviation that ambiguously refers to either an \"X.509\r\n public-key certificate in version 1 format\" or an \"X.509 attribute\r\n certificate in version 1 format\".\r\n Deprecated Usage: IDOCs MAY use this term as an abbreviation of\r\n \"version 1 X.509 public-key certificate\", but only after using the\r\n full term at the first instance. Otherwise, the term is ambiguous,\r\n because X.509 specifies both v1 public-key certificates and v1\r\n attribute certificates. (See: X.509 attribute certificate, X.509\r\n public-key certificate.)\r\n $ v1 CRL\r\n (N) Abbreviation of \"X.509 CRL in version 1 format\".\r\n Usage: IDOCs MAY use this abbreviation, but SHOULD use the full\r\n term at its first occurrence and define the abbreviation there.\r\n $ v2 certificate\r\n (N) Abbreviation of \"X.509 public-key certificate in version 2\r\n format\".\r\n Usage: IDOCs MAY use this abbreviation, but SHOULD use the full\r\n term at its first occurrence and define the abbreviation there.\r\n $ v2 CRL\r\n (N) Abbreviation of \"X.509 CRL in version 2 format\".\r\n Usage: IDOCs MAY use this abbreviation, but SHOULD use the full\r\n term at its first occurrence and define the abbreviation there.\r\n $ v3 certificate\r\n (N) Abbreviation of \"X.509 public-key certificate in version 3\r\n format\".\r\n Usage: IDOCs MAY use this abbreviation, but SHOULD use the full\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 393 of 436\n\nterm at its first occurrence and define the abbreviation there.\r\n $ valid certificate\r\n 1. (I) A digital certificate that can be validated successfully.\r\n (See: validate, verify.)\r\n 2. (I) A digital certificate for which the binding of the data\r\n items can be trusted.\r\n $ valid signature\r\n (D) Synonym for \"verified signature\".\r\nShirey Informational [Page 330]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this synonym. This Glossary\r\n recommends saying \"validate the certificate\" and \"verify the\r\n signature\"; therefore, it would be inconsistent to say that a\r\n signature is \"valid\". (See: validate, verify.)\r\n $ validate\r\n 1. (I) Establish the soundness or correctness of a construct.\r\n Example: certificate validation. (See: validate vs. verify.)\r\n 2. (I) To officially approve something, sometimes in relation to a\r\n standard. Example: NIST validates cryptographic modules for\r\n conformance with [FP140].\r\n $ validate vs. verify\r\n Usage: To ensure consistency and align with ordinary English\r\n usage, IDOCs SHOULD comply with the following two rules:\r\n - Rule 1: Use \"validate\" when referring to a process intended to\r\n establish the soundness or correctness of a construct (e.g.,\r\n \"certificate validation\"). (See: validate.)\r\n - Rule 2: Use \"verify\" when referring to a process intended to\r\n test or prove the truth or accuracy of a fact or value (e.g.,\r\n \"authenticate\"). (See: verify.)\r\n Tutorial: The Internet security community sometimes uses these two\r\n terms inconsistently, especially in a PKI context. Most often,\r\n however, we say \"verify the signature\" but say \"validate the\r\n certificate\". That is, we \"verify\" atomic truths but \"validate\"\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 394 of 436\n\ndata structures, relationships, and systems that are composed of\r\n or depend on verified items. This usage has a basis in Latin:\r\n The word \"valid\" derives from a Latin word that means \"strong\".\r\n Thus, to validate means to check that a construct is sound. For\r\n example, a certificate user validates a public-key certificate to\r\n establish trust in the binding that the certificate asserts\r\n between an identity and a key. This can include checking various\r\n aspects of the certificate's construction, such as verifying the\r\n digital signature on the certificate by performing calculations,\r\n verifying that the current time is within the certificate's\r\n validity period, and validating a certification path involving\r\n additional certificates.\r\n The word \"verify\" derives from a Latin word that means \"true\".\r\n Thus, to verify means to check the truth of an assertion by\r\n examining evidence or performing tests. For example, to verify an\r\n identity, an authentication process examines identification\r\n information that is presented or generated. To validate a\r\n certificate, a certificate user verifies the digital signature on\r\n the certificate by performing calculations, verifies that the\r\nShirey Informational [Page 331]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n current time is within the certificate's validity period, and may\r\n need to validate a certification path involving additional\r\n certificates.\r\n $ validation\r\n (I) See: validate vs. verify.\r\n $ validity period\r\n (I) /PKI/ A data item in a digital certificate that specifies the\r\n time period for which the binding between data items (especially\r\n between the subject name and the public key value in a public-key\r\n certificate) is valid, except if the certificate appears on a CRL\r\n or the key appears on a CKL. (See: cryptoperiod, key lifetime.)\r\n $ value-added network (VAN)\r\n (I) A computer network or subnetwork (usually a commercial\r\n enterprise) that transmits, receives, and stores EDI transactions\r\n on behalf of its users.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 395 of 436\n\nTutorial: A VAN may also provide additional services, ranging from\r\n EDI format translation, to EDI-to-FAX conversion, to integrated\r\n business systems.\r\n $ VAN\r\n (I) See: value-added network.\r\n $ verification\r\n 1. (I) /authentication/ The process of examining information to\r\n establish the truth of a claimed fact or value. (See: validate vs.\r\n verify, verify. Compare: authentication.)\r\n 2. (N) /COMPUSEC/ The process of comparing two levels of system\r\n specification for proper correspondence, such as comparing a\r\n security model with a top-level specification, a top-level\r\n specification with source code, or source code with object code.\r\n [NCS04]\r\n $ verified design\r\n (O) See: TCSEC Class A1.\r\n $ verify\r\n (I) To test or prove the truth or accuracy of a fact or value.\r\n (See: validate vs. verify, verification. Compare: authenticate.)\r\n $ vet\r\n (I) /verb/ To examine or evaluate thoroughly. (Compare:\r\n authenticate, identity proofing, validate, verify.)\r\nShirey Informational [Page 332]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ violation\r\n See: security violation.\r\n $ virtual private network (VPN)\r\n (I) A restricted-use, logical (i.e., artificial or simulated)\r\n computer network that is constructed from the system resources of\r\n a relatively public, physical (i.e., real) network (e.g., the\r\n Internet), often by using encryption (located at hosts or\r\n gateways), and often by tunneling links of the virtual network\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 396 of 436\n\nacross the real network. (See: tunnel.)\r\n Tutorial: A VPN is generally less expensive to build and operate\r\n than a dedicated real network, because the virtual network shares\r\n the cost of system resources with other users of the underlying\r\n real network. For example, if a corporation has LANs at several\r\n different sites, each connected to the Internet by a firewall, the\r\n corporation could create a VPN by using encrypted tunnels to\r\n connect from firewall to firewall across the Internet.\r\n $ virus\r\n (I) A self-replicating (and usually hidden) section of computer\r\n software (usually malicious logic) that propagates by infecting --\r\n i.e., inserting a copy of itself into and becoming part of --\r\n another program. A virus cannot run by itself; it requires that\r\n its host program be run to make the virus active.\r\n $ Visa Cash\r\n (O) A smartcard-based electronic money system that incorporates\r\n cryptography and can be used to make payments via the Internet.\r\n (See: IOTP.)\r\n $ volatile media\r\n (I) Storage media that require an external power supply to\r\n maintain stored information. (Compare: non-volatile media,\r\n permanent storage.)\r\n $ VPN\r\n (I) See: virtual private network.\r\n $ vulnerability\r\n (I) A flaw or weakness in a system's design, implementation, or\r\n operation and management that could be exploited to violate the\r\n system's security policy. (See: harden.)\r\n Tutorial: A system can have three types of vulnerabilities: (a)\r\n vulnerabilities in design or specification; (b) vulnerabilities in\r\n implementation; and (c) vulnerabilities in operation and\r\n management. Most systems have one or more vulnerabilities, but\r\nShirey Informational [Page 333]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 397 of 436\n\nthis does not mean that the systems are too flawed to use. Not\r\n every threat results in an attack, and not every attack succeeds.\r\n Success depends on the degree of vulnerability, the strength of\r\n attacks, and the effectiveness of any countermeasures in use. If\r\n the attacks needed to exploit a vulnerability are very difficult\r\n to carry out, then the vulnerability may be tolerable. If the\r\n perceived benefit to an attacker is small, then even an easily\r\n exploited vulnerability may be tolerable. However, if the attacks\r\n are well understood and easily made, and if the vulnerable system\r\n is employed by a wide range of users, then it is likely that there\r\n will be enough motivation for someone to launch an attack.\r\n $ W3\r\n (D) Synonym for WWW.\r\n Deprecated Abbreviation: This abbreviation could be confused with\r\n W3C; use \"WWW\" instead.\r\n $ W3C\r\n (N) See: World Wide Web Consortium.\r\n $ war dialer\r\n (I) /slang/ A computer program that automatically dials a series\r\n of telephone numbers to find lines connected to computer systems,\r\n and catalogs those numbers so that a cracker can try to break the\r\n systems.\r\n Deprecated Usage: IDOCs that use this term SHOULD state a\r\n definition for it because the term could confuse international\r\n readers.\r\n $ Wassenaar Arrangement\r\n (N) The Wassenaar Arrangement on Export Controls for Conventional\r\n Arms and Dual-Use Goods and Technologies is a global, multilateral\r\n agreement approved by 33 countries in July 1996 to contribute to\r\n regional and international security and stability, by promoting\r\n information exchange concerning, and greater responsibility in,\r\n transfers of arms and dual-use items, thus preventing\r\n destabilizing accumulations. (See: International Traffic in Arms\r\n Regulations.)\r\n Tutorial: The Arrangement began operations in September 1996 with\r\n headquarters in Vienna. The participating countries were\r\n Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech\r\n Republic, Denmark, Finland, France, Germany, Greece, Hungary,\r\n Ireland, Italy, Japan, Luxembourg, Netherlands, New Zealand,\r\n Norway, Poland, Portugal, Republic of Korea, Romania, Russian\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 398 of 436\n\nShirey Informational [Page 334]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Federation, Slovak Republic, Spain, Sweden, Switzerland, Turkey,\r\n Ukraine, United Kingdom, and United States.\r\n Participating countries seek through their national policies to\r\n ensure that transfers do not contribute to the development or\r\n enhancement of military capabilities that undermine the goals of\r\n the arrangement, and are not diverted to support such\r\n capabilities. The countries maintain effective export controls for\r\n items on the agreed lists, which are reviewed periodically to\r\n account for technological developments and experience gained.\r\n Through transparency and exchange of views and information,\r\n suppliers of arms and dual-use items can develop common\r\n understandings of the risks associated with their transfer and\r\n assess the scope for coordinating national control policies to\r\n combat these risks. Members provide semi-annual notification of\r\n arms transfers, covering seven categories derived from the UN\r\n Register of Conventional Arms. Members also report transfers or\r\n denials of transfers of certain controlled dual-use items.\r\n However, the decision to transfer or deny transfer of any item is\r\n the sole responsibility of each participating country. All\r\n measures undertaken with respect to the arrangement are in\r\n accordance with national legislation and policies and are\r\n implemented on the basis of national discretion.\r\n $ watermarking\r\n See: digital watermarking.\r\n $ weak key\r\n (I) In the context of a particular cryptographic algorithm, a key\r\n value that provides poor security. (See: strong.)\r\n Example: The DEA has four \"weak keys\" [Schn] for which encryption\r\n produces the same result as decryption. It also has ten pairs of\r\n \"semi-weak keys\" [Schn] (a.k.a. \"dual keys\" [FP074]) for which\r\n encryption with one key in the pair produces the same result as\r\n decryption with the other key.\r\n $ web, Web\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 399 of 436\n\n1. (I) /not capitalized/ IDOCs SHOULD NOT capitalize \"web\" when\r\n using the term (usually as an adjective) to refer generically to\r\n technology -- such as web browsers, web servers, HTTP, and HTML --\r\n that is used in the Web or similar networks.\r\n 2. (I) /capitalized/ IDOCs SHOULD capitalize \"Web\" when using the\r\n term (as either a noun or an adjective) to refer specifically to\r\n the World Wide Web. (Similarly, see: internet.)\r\nShirey Informational [Page 335]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: IDOCs SHOULD NOT use \"web\" or \"Web\" in a way that might\r\n confuse these definitions with the PGP \"web of trust\". When using\r\n Web as an abbreviation for \"World Wide Web\", IDOCs SHOULD fully\r\n spell out the term at the first instance of usage.\r\n $ web of trust\r\n (D) /PGP/ A PKI architecture in which each certificate user\r\n defines their own trust anchor(s) by depending on personal\r\n relationships. (See: trust anchor. Compare: hierarchical PKI, mesh\r\n PKI.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term except with\r\n reference to PGP. This term mixes concepts in potentially\r\n misleading ways; e.g., this architecture does not depend on World\r\n Wide Web technology. Instead of this term, IDOCs MAY use \"trust-\r\n file PKI\". (See: web, Web).\r\n Tutorial: This type of architecture does not usually include\r\n public repositories of certificates. Instead, each certificate\r\n user builds their own, private repository of trusted public keys\r\n by making personal judgments about being able to trust certain\r\n people to be holding properly certified keys of other people. It\r\n is this set of person-to-person relationships from which the\r\n architecture gets its name.\r\n $ web server\r\n (I) A software process that runs on a host computer connected to a\r\n network and responds to HTTP requests made by client web browsers.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 400 of 436\n\n$ WEP\r\n (N) See: Wired Equivalency Protocol.\r\n $ Wired Equivalent Privacy (WEP)\r\n (N) A cryptographic protocol that is defined in the IEEE 802.11\r\n standard and encapsulates the packets on wireless LANs. Usage:\r\n a.k.a. \"Wired Equivalency Protocol\".\r\n Tutorial: The WEP design, which uses RC4 to encrypt both the plain\r\n text and a CRC, has been shown to be flawed in multiple ways; and\r\n it also has often suffered from flawed implementation and\r\n management.\r\n $ wiretapping\r\n (I) An attack that intercepts and accesses information contained\r\n in a data flow in a communication system. (See: active\r\n wiretapping, end-to-end encryption, passive wiretapping, secondary\r\n definition under \"interception\".)\r\nShirey Informational [Page 336]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Usage: Although the term originally referred to making a\r\n mechanical connection to an electrical conductor that links two\r\n nodes, it is now used to refer to accessing information from any\r\n sort of medium used for a link or even from a node, such as a\r\n gateway or subnetwork switch.\r\n Tutorial: Wiretapping can be characterized according to intent:\r\n - \"Active wiretapping\" attempts to alter the data or otherwise\r\n affect the flow.\r\n - \"Passive wiretapping\" only attempts to observe the data flow\r\n and gain knowledge of information contained in it.\r\n $ work factor\r\n 1a. (I) /COMPUSEC/ The estimated amount of effort or time that can\r\n be expected to be expended by a potential intruder to penetrate a\r\n system, or defeat a particular countermeasure, when using\r\n specified amounts of expertise and resources. (See: brute force,\r\n impossible, strength.)\r\n 1b. (I) /cryptography/ The estimated amount of computing power and\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 401 of 436\n\ntime needed to break a cryptographic system. (See: brute force,\r\n impossible, strength.)\r\n $ World Wide Web (\"the Web\", WWW)\r\n (N) The global, hypermedia-based collection of information and\r\n services that is available on Internet servers and is accessed by\r\n browsers using Hypertext Transfer Protocol and other information\r\n retrieval mechanisms. (See: web vs. Web, [R2084].)\r\n $ World Wide Web Consortium (W3C)\r\n (N) Created in October 1994 to develop and standardize protocols\r\n to promote the evolution and interoperability of the Web, and now\r\n consisting of hundreds of member organizations (commercial firms,\r\n governmental agencies, schools, and others).\r\n Tutorial: W3C Recommendations are developed through a process\r\n similar to that of the standards published by other organizations,\r\n such as the IETF. The W3 Recommendation Track (i.e., standards\r\n track) has four levels of increasing maturity: Working, Candidate\r\n Recommendation, Proposed Recommendation, and W3C Recommendation.\r\n W3C Recommendations are similar to the standards published by\r\n other organizations. (Compare: Internet Standard, ISO.)\r\n $ worm\r\n (I) A computer program that can run independently, can propagate a\r\n complete working version of itself onto other hosts on a network,\r\n and may consume system resources destructively. (See: mobile code,\r\n Morris Worm, virus.)\r\nShirey Informational [Page 337]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n $ wrap\r\n 1. (N) To use cryptography to provide data confidentiality service\r\n for keying material. (See: encrypt, wrapping algorithm, wrapping\r\n key. Compare: seal, shroud.)\r\n 2. (D) To use cryptography to provide data confidentiality service\r\n for data in general.\r\n Deprecated Usage: IDOCs SHOULD NOT use this term with definition 2\r\n because that duplicates the meaning of the more widely understood\r\n \"encrypt\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 402 of 436\n\n$ wrapping algorithm\r\n (N) An encryption algorithm that is specifically intended for use\r\n in encrypting keys. (See: KEK, wrap.)\r\n $ wrapping key\r\n (N) Synonym for \"KEK\". (See: encrypt. Compare: seal, shroud.)\r\n $ write\r\n (I) /security model/ A system operation that causes a flow of\r\n information from a subject to an object. (See: access mode.\r\n Compare: read.)\r\n $ WWW\r\n (I) See: World Wide Web.\r\n $ X.400\r\n (N) An ITU-T Recommendation [X400] that is one part of a joint\r\n ITU-T/ISO multi-part standard (X.400-X.421) that defines the\r\n Message Handling Systems. (The ISO equivalent is IS 10021, parts\r\n 1-7.) (See: Message Handling Systems.)\r\n $ X.500\r\n (N) An ITU-T Recommendation [X500] that is one part of a joint\r\n ITU-T/ISO multi-part standard (X.500-X.525) that defines the X.500\r\n Directory, a conceptual collection of systems that provide\r\n distributed directory capabilities for OSI entities, processes,\r\n applications, and services. (The ISO equivalent is IS 9594-1 and\r\n related standards, IS 9594-x.) (See: directory vs. Directory,\r\n X.509.)\r\n Tutorial: The X.500 Directory is structured as a tree (the\r\n Directory Information Tree), and information is stored in\r\n directory entries. Each entry is a collection of information about\r\n one object, and each object has a DN. A directory entry is\r\n composed of attributes, each with a type and one or more values.\r\n For example, if a PKI uses the Directory to distribute\r\nShirey Informational [Page 338]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n certificates, then the X.509 public-key certificate of an end user\r\n is normally stored as a value of an attribute of type\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 403 of 436\n\n\"userCertificate\" in the Directory entry that has the DN that is\r\n the subject of the certificate.\r\n $ X.509\r\n (N) An ITU-T Recommendation [X509] that defines a framework to\r\n provide and support data origin authentication and peer entity\r\n authentication, including formats for X.509 public-key\r\n certificates, X.509 attribute certificates, and X.509 CRLs. (The\r\n ISO equivalent is IS 9498-4.) (See: X.500.)\r\n Tutorial: X.509 describes two \"levels\" of authentication: \"simple\r\n authentication\" and \"strong authentication\". It recommends, \"While\r\n simple authentication offers some limited protection against\r\n unauthorized access, only strong authentication should be used as\r\n the basis for providing secure services.\"\r\n $ X.509 attribute certificate\r\n (N) An attribute certificate in the version 1 (v1) format defined\r\n by X.509. (The v1 designation for an X.509 attribute certificate\r\n is disjoint from the v1 designation for an X.509 public-key\r\n certificate, and from the v1 designation for an X.509 CRL.)\r\n Tutorial: An X.509 attribute certificate has a \"subject\" field,\r\n but the attribute certificate is a separate data structure from\r\n that subject's public-key certificate. A subject may have multiple\r\n attribute certificates associated with each of its public-key\r\n certificates, and an attribute certificate may be issued by a\r\n different CA than the one that issued the associated public-key\r\n certificate.\r\n An X.509 attribute certificate contains a sequence of data items\r\n and has a digital signature that is computed from that sequence.\r\n Besides the signature, an attribute certificate contains items 1\r\n through 9 listed below:\r\n 1. version Identifies v1.\r\n 2. subject Is one of the following:\r\n 2a. baseCertificateID Issuer and serial number of an\r\n X.509 public-key certificate.\r\n 2b. subjectName DN of the subject.\r\n 3. issuer DN of the issuer (the CA who signed).\r\n 4. signature OID of algorithm that signed the cert.\r\n 5. serialNumber Certificate serial number;\r\n an integer assigned by the issuer.\r\n 6. attCertValidityPeriod Validity period; a pair of UTCTime\r\n values: \"not before\" and \"not after\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 404 of 436\n\nShirey Informational [Page 339]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 7. attributes Sequence of attributes describing the\r\n subject.\r\n 8. issuerUniqueId Optional, when a DN is not sufficient.\r\n 9. extensions Optional.\r\n $ X.509 certificate\r\n (N) Synonym for \"X.509 public-key certificate\".\r\n Usage: IDOCs MAY use this term as an abbreviation of \"X.509\r\n public-key certificate\", but only after using the full term at the\r\n first instance. Otherwise, the term is ambiguous, because X.509\r\n specifies both public-key certificates and attribute certificates.\r\n (See: X.509 attribute certificate, X.509 public-key certificate.)\r\n Deprecated Usage: IDOCs SHOULD NOT use this term as an\r\n abbreviation of \"X.509 attribute certificate\", because the term is\r\n much more commonly used to mean \"X.509 public-key certificate\"\r\n and, therefore, is likely to be misunderstood.\r\n $ X.509 certificate revocation list (CRL)\r\n (N) A CRL in one of the formats defined by X.509 -- version 1 (v1)\r\n or version 2 (v2). (The v1 and v2 designations for an X.509 CRL\r\n are disjoint from the v1 and v2 designations for an X.509 public-\r\n key certificate, and from the v1 designation for an X.509\r\n attribute certificate.) (See: certificate revocation.)\r\n Usage: IDOCs SHOULD NOT refer to an X.509 CRL as a digital\r\n certificate; however, note that an X.509 CRL does meet this\r\n Glossary's definition of \"digital certificate\". That is, like a\r\n digital certificate, an X.509 CRL makes an assertion and is signed\r\n by a CA. But instead of binding a key or other attributes to a\r\n subject, an X.509 CRL asserts that certain previously issued,\r\n X.509 certificates have been revoked.\r\n Tutorial: An X.509 CRL contains a sequence of data items and has a\r\n digital signature computed on that sequence. Besides the\r\n signature, both v1 and v2 contain items 2 through 6b listed below.\r\n Version 2 contains item 1 and may optionally contain 6c and 7.\r\n 1. version Optional. If present, identifies v2.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 405 of 436\n\n2. signature OID of the algorithm that signed CRL.\r\n 3. issuer DN of the issuer (the CA who signed).\r\n 4. thisUpdate A UTCTime value.\r\n 5. nextUpdate A UTCTime value.\r\n 6. revokedCertificates 3-tuples of 6a, 6b, and (optional) 6c:\r\n 6a. userCertificate A certificate's serial number.\r\n 6b. revocationDate UTCTime value for the revocation date.\r\n 6c. crlEntryExtensions Optional.\r\nShirey Informational [Page 340]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n 7. crlExtensions Optional.\r\n $ X.509 public-key certificate\r\n (N) A public-key certificate in one of the formats defined by\r\n X.509 -- version 1 (v1), version 2 (v2), or version 3 (v3). (The\r\n v1 and v2 designations for an X.509 public-key certificate are\r\n disjoint from the v1 and v2 designations for an X.509 CRL, and\r\n from the v1 designation for an X.509 attribute certificate.)\r\n Tutorial: An X.509 public-key certificate contains a sequence of\r\n data items and has a digital signature computed on that sequence.\r\n Besides the signature, all three versions contain items 1 through\r\n 7 listed below. Only v2 and v3 certificates may also contain items\r\n 8 and 9, and only v3 may contain item 10.\r\n 1. version Identifies v1, v2, or v3.\r\n 2. serialNumber Certificate serial number;\r\n an integer assigned by the issuer.\r\n 3. signature OID of algorithm that was used to\r\n sign the certificate.\r\n 4. issuer DN of the issuer (the CA who signed).\r\n 5. validity Validity period; a pair of UTCTime\r\n values: \"not before\" and \"not after\".\r\n 6. subject DN of entity who owns the public key.\r\n 7. subjectPublicKeyInfo Public key value and algorithm OID.\r\n 8. issuerUniqueIdentifier Defined for v2, v3; optional.\r\n 9. subjectUniqueIdentifier Defined for v2, v2; optional.\r\n 10. extensions Defined only for v3; optional.\r\n $ X9\r\n (N) See: \"Accredited Standards Committee X9\" under \"ANSI\".\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 406 of 436\n\n$ XML\r\n (N) See: Extensible Markup Language.\r\n $ XML-Signature.\r\n (N) A W3C Recommendation (i.e., approved standard) that specifies\r\n XML syntax and processing rules for creating and representing\r\n digital signatures (based on asymmetric cryptography) that can be\r\n applied to any digital content (i.e., any data object) including\r\n other XML material.\r\n $ Yellow Book\r\n (D) /slang/ Synonym for \"Computer Security Requirements: Guidance\r\n for Applying the [U.S.] Department of Defense Trusted Computer\r\n System Evaluation Criteria in Specific Environments\" [CSC3] (See:\r\n \"first law\" under \"Courtney's laws\".)\r\nShirey Informational [Page 341]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n Deprecated Term: IDOCs SHOULD NOT use this term as a synonym for\r\n that or any other document. Instead, use the full proper name of\r\n the document or, in subsequent references, a conventional\r\n abbreviation. (See: Deprecated Usage under \"Green Book\", Rainbow\r\n Series.)\r\n $ zero-knowledge proof\r\n (I) /cryptography/ A proof-of-possession protocol whereby a system\r\n entity can prove possession of some information to another entity,\r\n without revealing any of that information. (See: proof-of-\r\n possession protocol.)\r\n $ zeroize\r\n 1. (I) Synonym for \"erase\". (See: sanitize.) Usage: Particularly\r\n with regard to erasing keys that are stored in a cryptographic\r\n module.\r\n 2. (O) Erase electronically stored data by altering the contents\r\n of the data storage so as to prevent the recovery of the data.\r\n [FP140]\r\n 3. (O) \"To remove or eliminate the key from a cryptoequipment or\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 407 of 436\n\nfill device.\" [C4009]\r\n Usage: The phrase \"zeroize the device\" normally is used to mean\r\n erasing all keys stored in the device, but sometimes means erasing\r\n all keying material in the device, or all cryptographic\r\n information in the device, or even all sensitive information in\r\n the device.\r\n $ zombie\r\n (I) /slang/ An Internet host computer that has been\r\n surreptitiously penetrated by an intruder that installed malicious\r\n daemon software to cause the host to operate as an accomplice in\r\n attacking other hosts, particularly in distributed attacks that\r\n attempt denial of service through flooding.\r\n Deprecated Usage: Other cultures likely use different metaphorical\r\n terms (such as \"robot\") for this concept, and some use this term\r\n for different concepts. Therefore, to avoid international\r\n misunderstanding, IDOCs SHOULD NOT use this term. Instead, use\r\n \"compromised, coopted computer\" or other explicitly descriptive\r\n terminology. (See: Deprecated Usage under \"Green Book\".)\r\n $ zone of control\r\n (O) /EMSEC/ Synonym for \"inspectable space\". [C4009] (See:\r\n TEMPEST.)\r\nShirey Informational [Page 342]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n5. Security Considerations\r\n This document mainly defines security terms and recommends how to use\r\n them. It also provides limited tutorial information about security\r\n aspects of Internet protocols, but it does not describe in detail the\r\n vulnerabilities of, or threats to, specific protocols and does not\r\n definitively describe mechanisms that protect specific protocols.\r\n6. Normative Reference\r\n [R2119] Bradner, S., \"Key words for use in RFCs to Indicate\r\n Requirement Levels\", BCP 14, RFC 2119, March 1997.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 408 of 436\n\n7. Informative References\r\n This Glossary focuses on the Internet Standards Process. Therefore,\r\n this set of informative references emphasizes international,\r\n governmental, and industrial standards documents. Some RFCs that are\r\n especially relevant to Internet security are mentioned in Glossary\r\n entries in square brackets (e.g., \"[R1457]\" in the entry for\r\n \"security label\") and are listed here; some other RFCs are mentioned\r\n in parentheses (e.g., \"(RFC 959)\" in the entry for \"File Transport\r\n Protocol\") but are not listed here.\r\n [A1523] American National Standards Institute, \"American National\r\n Standard Telecom Glossary\", ANSI T1.523-2001.\r\n [A3092] ---, \"American National Standard Data Encryption Algorithm\",\r\n ANSI X3.92-1981, 30 December 1980.\r\n [A9009] ---, \"Financial Institution Message Authentication\r\n (Wholesale)\", ANSI X9.9-1986, 15 August 1986.\r\n [A9017] ---, \"Financial Institution Key Management (Wholesale)\",\r\n X9.17, 4 April 1985. (Defines procedures for manual and\r\n automated management of keying material and uses DES to\r\n provide key management for a variety of operational\r\n environments.)\r\n [A9042] ---, \"Public key Cryptography for the Financial Service\r\n Industry: Agreement of Symmetric Keys Using Diffie-Hellman\r\n and MQV Algorithms\", X9.42, 29 January 1999. (See: Diffie-\r\n Hellman-Merkle.)\r\n [A9052] ---, \"Triple Data Encryption Algorithm Modes of Operation\",\r\n X9.52-1998, ANSI approval 9 November 1998.\r\nShirey Informational [Page 343]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [A9062] ---, \"Public Key Cryptography for the Financial Services\r\n Industry: The Elliptic Curve Digital Signature Algorithm\r\n (ECDSA)\", X9.62-1998, ANSI approval 7 January 1999.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 409 of 436\n\n[A9063] ---, \"Public Key Cryptography for the Financial Services\r\n Industry: Key Agreement and Key Transport Using Elliptic\r\n Curve Cryptography\", X9.63-2001.\r\n [ACM] Association for Computing Machinery, \"Communications of the\r\n ACM\", July 1998 issue with: M. Yeung, \"Digital\r\n Watermarking\"; N. Memom and P. Wong, \"Protecting Digital\r\n Media Content\"; and S. Craver, B.-L. Yeo, and M. Yeung,\r\n \"Technical Trials and Legal Tribulations\".\r\n [Ande] Anderson, J., \"Computer Security Technology Planning Study\",\r\n ESD-TR-73-51, Vols. I and II, USAF Electronics Systems Div.,\r\n Bedford, MA, October 1972. (Available as AD-758206/772806,\r\n National Technical Information Service, Springfield, VA.)\r\n [ANSI] American National Standards Institute, \"Role Based Access\r\n Control\", Secretariat, Information Technology Industry\r\n Council, BSR INCITS 359, DRAFT, 10 November 2003.\r\n [Army] U.S. Army Corps of Engineers, \"Electromagnetic Pulse (EMP)\r\n and Tempest Protection for Facilities\", EP 1110-3-2, 31\r\n December 1990.\r\n [B1822] Bolt Baranek and Newman Inc., \"Appendix H: Interfacing a\r\n Host to a Private Line Interface\", in \"Specifications for\r\n the Interconnection of a Host and an IMP\", BBN Report No.\r\n 1822, revised, December 1983.\r\n [B4799] ---, \"A History of the Arpanet: The First Decade\", BBN\r\n Report No. 4799, April 1981.\r\n [Bell] Bell, D. and L. LaPadula, \"Secure Computer Systems:\r\n Mathematical Foundations and Model\", M74-244, The MITRE\r\n Corporation, Bedford, MA, May 1973. (Available as AD-771543,\r\n National Technical Information Service, Springfield, VA.)\r\n [Biba] K. Biba, \"Integrity Considerations for Secure Computer\r\n Systems\", ESD-TR-76-372, USAF Electronic Systems Division,\r\n Bedford, MA, April 1977.\r\n [BN89] Brewer, D. and M. Nash, \"The Chinese wall security policy\",\r\n in \"Proceedings of IEEE Symposium on Security and Privacy\",\r\n May 1989, pp. 205-214.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 410 of 436\n\nShirey Informational [Page 344]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [BS7799] British Standards Institution, \"Information Security\r\n Management, Part 1: Code of Practice for Information\r\n Security Management\", BS 7799-1:1999, 15 May 1999.\r\n ---, \"Information Security Management, Part 2: Specification\r\n for Information Security Management Systems\", BS 7799-\r\n 2:1999, 15 May 1999.\r\n [C4009] Committee on National Security Systems (U.S. Government),\r\n \"National Information Assurance (IA) Glossary\", CNSS\r\n Instruction No. 4009, revised June 2006.\r\n [CCIB] Common Criteria Implementation Board, \"Common Criteria for\r\n Information Technology Security Evaluation, Part 1:\r\n Introduction and General Model\", version 2.0, CCIB-98-026,\r\n May 1998.\r\n [Chau] D. Chaum, \"Untraceable Electronic Mail, Return Addresses,\r\n and Digital Pseudonyms\", in \"Communications of the ACM\",\r\n vol. 24, no. 2, February 1981, pp. 84-88.\r\n [Cheh] Cheheyl, M., Gasser, M., Huff, G., and J. Millen, \"Verifying\r\n Security\", in \"ACM Computing Surveys\", vol. 13, no. 3,\r\n September 1981, pp. 279-339.\r\n [Chris] Chrissis, M. et al, 1993. \"SW-CMM [Capability Maturity Model\r\n for Software Version\", Release 3.0, Software Engineering\r\n Institute, Carnegie Mellon University, August 1996.\r\n [CIPSO] Trusted Systems Interoperability Working Group, \"Common IP\r\n Security Option\", version 2.3, 9 March 1993.\r\n [Clark] Clark, D. and D. Wilson, \"A Comparison of Commercial and\r\n Military computer Security Policies\", in \"Proceedings of the\r\n IEEE Symposium on Security and Privacy\", April 1987, pp.\r\n 184-194.\r\n [Cons] NSA, \"Consistency Instruction Manual for Development of U.S.\r\n Government Protection Profiles for Use in Basic Robustness\r\n Environments\", Release 2.0, 1 March 2004\r\n [CORBA] Object Management Group, Inc., \"CORBAservices: Common Object\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 411 of 436\n\nService Specification\", December 1998.\r\n [CSC1] U.S. DoD Computer Security Center, \"Department of Defense\r\n Trusted Computer System Evaluation Criteria\", CSC-STD-001-\r\n 83, 15 August 1983. (Superseded by [DoD1].)\r\nShirey Informational [Page 345]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [CSC2] ---, \"Department of Defense Password Management Guideline\",\r\n CSC-STD-002-85, 12 April 1985.\r\n [CSC3] ---, \"Computer Security Requirements: Guidance for Applying\r\n the Department of Defense Trusted Computer System Evaluation\r\n Criteria in Specific Environments\", CSC-STD-003-85, 25 June\r\n 1985.\r\n [CSOR] U.S. Department of Commerce, \"General Procedures for\r\n Registering Computer Security Objects\", National Institute\r\n of Standards Interagency Report 5308, December 1993.\r\n [Daem] Daemen, J. and V. Rijmen, \"Rijndael, the advanced encryption\r\n standard\", in \"Dr. Dobb's Journal\", vol. 26, no. 3, March\r\n 2001, pp. 137-139.\r\n [DC6/9] Director of Central Intelligence, \"Physical Security\r\n Standards for Sensitive Compartmented Information\r\n Facilities\", DCI Directive 6/9, 18 November 2002.\r\n [Denn] Denning, D., \"A Lattice Model of Secure Information Flow\",\r\n in \"Communications of the ACM\", vol. 19, no. 5, May 1976,\r\n pp. 236-243.\r\n [Denns] Denning, D. and P. Denning, \"Data Security\", in \"ACM\r\n Computing Surveys\", vol. 11, no. 3, September 1979, pp. 227-\r\n 249.\r\n [DH76] Diffie, W. and M. Hellman, \"New Directions in Cryptography\",\r\n in \"IEEE Transactions on Information Theory\", vol. IT-22,\r\n no. 6, November 1976, pp. 644-654. (See: Diffie-Hellman-\r\n Merkle.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 412 of 436\n\n[DoD1] U.S. DoD, \"Department of Defense Trusted Computer System\r\n Evaluation Criteria\", DoD 5200.28-STD, 26 December 1985.\r\n (Supersedes [CSC1].) (Superseded by DoD Directive 8500.1.)\r\n [DoD4] ---, \"NSA Key Recovery Assessment Criteria\", 8 June 1998.\r\n [DoD5] ---, Directive 5200.1, \"DoD Information Security Program\",\r\n 13 December 1996.\r\n [DoD6] ---, \"Department of Defense Technical Architecture Framework\r\n for Information Management, Volume 6: Department of Defense\r\n (DoD) Goal Security Architecture\", Defense Information\r\n Systems Agency, Center for Standards, version 3.0, 15 April\r\n 1996.\r\nShirey Informational [Page 346]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [DoD7] ---, \"X.509 Certificate Policy for the United States\r\n Department of Defense\", version 7, 18 December 2002.\r\n (Superseded by [DoD9].)\r\n [DoD9] ---, \"X.509 Certificate Policy for the United States\r\n Department of Defense\", version 9, 9 February 2005.\r\n [DoD10] ---, \"DoD Architecture Framework, Version 1: Deskbook\", 9\r\n February 2004.\r\n [DSG] American Bar Association, \"Digital Signature Guidelines:\r\n Legal Infrastructure for Certification Authorities and\r\n Secure Electronic Commerce\", Chicago, IL, 1 August 1996.\r\n (See: [PAG].)\r\n [ElGa] El Gamal, T., \"A Public-Key Cryptosystem and a Signature\r\n Scheme Based on Discrete Logarithms\", in \"IEEE Transactions\r\n on Information Theory\", vol. IT-31, no. 4, 1985, pp. 469-\r\n 472.\r\n [EMV1] Europay International S.A., MasterCard International\r\n Incorporated, and Visa International Service Association,\r\n \"EMV '96 Integrated Circuit Card Specification for Payment\r\n Systems\", version 3.1.1, 31 May 1998.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 413 of 436\n\n[EMV2] ---, \"EMV '96 Integrated Circuit Card Terminal Specification\r\n for Payment Systems\", version 3.1.1, 31 May 1998.\r\n [EMV3] ---, \"EMV '96 Integrated Circuit Card Application\r\n Specification for Payment Systems\", version 3.1.1, 31 May\r\n 1998.\r\n [F1037] U.S. General Services Administration, \"Glossary of\r\n Telecommunications Terms\", FED STD 1037C, 7 August 1996.\r\n [For94] Ford, W., \"Computer Communications Security: Principles,\r\n Standard Protocols and Techniques\", ISBN 0-13-799453-2,\r\n 1994.\r\n [For97] --- and M. Baum, \"Secure Electronic Commerce: Building the\r\n Infrastructure for Digital Signatures and Encryption\", ISBN\r\n 0-13-476342-4, 1994.\r\n [FP001] U.S. Department of Commerce, \"Code for Information\r\n Interchange\", Federal Information Processing Standards\r\n Publication (FIPS PUB) 1, 1 November 1968.\r\nShirey Informational [Page 347]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [FP031] ---, \"Guidelines for Automatic Data Processing Physical\r\n Security and Risk Management\", FIPS PUB 31, June 1974.\r\n [FP039] ---, \"Glossary for Computer Systems Security\", FIPS PUB 39,\r\n 15 February 1976.\r\n [FP041] ---, \"Computer Security Guidelines for Implementing the\r\n Privacy Act of 1974\", FIPS PUB 41, 30 May 1975.\r\n [FP046] ---, \"Data Encryption Standard (DES)\", FIPS PUB 46-3, 25\r\n October 1999.\r\n [FP074] ---, \"Data Encryption Standard (DES)\", FIPS PUB 46-3, 25\r\n October 1999.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 414 of 436\n\n[FP081] ---, \"DES Modes of Operation\", FIPS PUB 81, 2 December 1980.\r\n [FP087] ---, \"Guidelines for ADP Contingency Planning\", FIPS PUB 87,\r\n 27 March 1981.\r\n [FP102] ---, \"Guideline for Computer Security Certification and\r\n Accreditation\", FIPS PUB 102, 27 September 1983.\r\n [FP113] ---, \"Computer Data Authentication\", FIPS PUB 113, 30 May\r\n 1985.\r\n [FP140] ---, \"Security Requirements for Cryptographic Modules\", FIPS\r\n PUB 140-2, 25 May 2001; with change notice 4, 3 December\r\n 2002.\r\n [FP151] ---, \"Portable Operating System Interface (POSIX) -- System\r\n Application Program Interface [C Language]\", FIPS PUB 151-2,\r\n 12 May 1993\r\n [FP180] ---, \"Secure Hash Standard\", FIPS PUB 180-2, August 2000;\r\n with change notice 1, 25 February 2004.\r\n [FP185] ---, \"Escrowed Encryption Standard\", FIPS PUB 185, 9\r\n February 1994.\r\n [FP186] ---, \"Digital Signature Standard (DSS)\", FIPS PUB 186-2, 27\r\n June 2000; with change notice 1, 5 October 2001.\r\n [FP188] ---, \"Standard Security Label for Information Transfer\",\r\n FIPS PUB 188, 6 September 1994.\r\n [FP191] ---, \"Guideline for the Analysis of Local Area Network\r\n Security\", FIPS PUB 191, 9 November 1994.\r\nShirey Informational [Page 348]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [FP197] ---, \"Advanced Encryption Standard\", FIPS PUB 197, 26\r\n November 2001.\r\n [FP199] ---, \"Standards for Security Categorization of Federal\r\n Information and Information Systems \", FIPS PUB 199,\r\n December 2003.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 415 of 436\n\n[FPKI] ---, \"Public Key Infrastructure (PKI) Technical\r\n Specifications: Part A -- Technical Concept of Operations\",\r\n NIST, 4 September 1998.\r\n [Gass] Gasser, M., \"Building a Secure Computer System\", Van\r\n Nostrand Reinhold Company, New York, 1988, ISBN 0-442-\r\n 23022-2.\r\n [Gray] Gray, J. and A. Reuter, \"Transaction Processing: Concepts\r\n and Techniques\", Morgan Kaufmann Publishers, Inc., 1993.\r\n [Hafn] Hafner, K. and M. Lyon, \"Where Wizards Stay Up Late: The\r\n Origins of the Internet\", Simon \u0026 Schuster, New York, 1996.\r\n [Huff] Huff, G., \"Trusted Computer Systems -- Glossary\", MTR 8201,\r\n The MITRE Corporation, March 1981.\r\n [I3166] International Standards Organization, \"Codes for the\r\n Representation of Names of Countries and Their Subdivisions,\r\n Part 1: Country Codes\", ISO 3166-1:1997.\r\n ---, \"Codes for the Representation of Names of Countries and\r\n Their Subdivisions, Part 2: Country Subdivision Codes\",\r\n ISO/DIS 3166-2.\r\n ---, \"Codes for the Representation of Names of Countries and\r\n Their Subdivisions, Part 3: Codes for Formerly Used Names of\r\n Countries\", ISO/DIS 3166-3.\r\n [I7498-1] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection Reference Model, [Part 1:] Basic Reference\r\n Model\", ISO/IEC 7498-1. (Equivalent to ITU-T Recommendation\r\n X.200.)\r\n [I7498-2] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection Reference Model, Part 2: Security\r\n Architecture\", ISO/IEC 7499-2.\r\n [I7498-4] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection Reference Model, Part 4: Management\r\n Framework\", ISO/IEC 7498-4.\r\nShirey Informational [Page 349]\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 416 of 436\n\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [I7812] ---, \"Identification cards -- Identification of Issuers,\r\n Part 1: Numbering System\", ISO/IEC 7812-1:1993\r\n ---, \"Identification cards -- Identification of Issuers,\r\n Part 2: Application and Registration Procedures\", ISO/IEC\r\n 7812-2:1993.\r\n [I8073] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection, Transport Protocol Specification\", ISO IS\r\n 8073.\r\n [I8327] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection, Session Protocol Specification\", ISO IS\r\n 8327.\r\n [I8473] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection, Protocol for Providing the Connectionless\r\n Network Service\", ISO IS 8473.\r\n [I8802-2] ---, \"Information Processing Systems -- Local Area\r\n Networks, Part 2: Logical Link Control\", ISO IS 8802-2.\r\n (Equivalent to IEEE 802.2.)\r\n [I8802-3] ---, \"Information Processing Systems -- Local Area\r\n Networks, Part 3: Carrier Sense Multiple Access with\r\n Collision Detection (CSMA/CD) Access Method and Physical\r\n Layer Specifications\", ISO IS 8802-3. (Equivalent to IEEE\r\n 802.3.)\r\n [I8823] ---, \"Information Processing Systems -- Open Systems\r\n Interconnection -- Connection-Oriented Presentation Protocol\r\n Specification\", ISO IS 8823.\r\n [I9945] \"Portable Operating System Interface for Computer\r\n Environments\", ISO/IEC 9945-1: 1990.\r\n [IATF] NSA, \"Information Assurance Technical Framework\", Release 3,\r\n NSA, September 2000. (See: IATF.)\r\n [IDSAN] ---, \"Intrusion Detection System Analyzer Protection\r\n Profile\", version 1.1, NSA, 10 December 2001.\r\n [IDSSC] ---, \"Intrusion Detection System Scanner Protection\r\n Profile\", version 1.1, NSA, 10 December 2001.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 417 of 436\n\n[IDSSE] ---, \"Intrusion Detection System Sensor Protection Profile\",\r\n version 1.1, NSA, 10 December 2001.\r\nShirey Informational [Page 350]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [IDSSY] ---, \"Intrusion Detection System\", version 1.4, NSA, 4\r\n February 2002.\r\n [Ioan] Ioannidis, J. and M. Blaze, \"The Architecture and\r\n Implementation of Network Layer Security in UNIX\", in \"UNIX\r\n Security IV Symposium\", October 1993, pp. 29-39.\r\n [ITSEC] \"Information Technology Security Evaluation Criteria\r\n (ITSEC): Harmonised Criteria of France, Germany, the\r\n Netherlands, and the United Kingdom\", version 1.2, U.K.\r\n Department of Trade and Industry, June 1991.\r\n [JP1] U.S. DoD, \"Department of Defense Dictionary of Military and\r\n Associated Terms\", Joint Publication 1-02, as amended\r\n through 13 June 2007.\r\n [John] Johnson, N. and S. Jajodia, \"Exploring Steganography; Seeing\r\n the Unseen\", in \"IEEE Computer\", February 1998, pp. 26-34.\r\n [Kahn] Kahn, D., \"The Codebreakers: The Story of Secret Writing\",\r\n The Macmillan Company, New York, 1967.\r\n [Knut] Knuth, D., Chapter 3 (\"Random Numbers\") of Volume 2\r\n (\"Seminumerical Algorithms\") of \"The Art of Computer\r\n Programming\", Addison-Wesley, Reading, MA, 1969.\r\n [Kuhn] Kuhn, M. and R. Anderson, \"Soft Tempest: Hidden Data\r\n Transmission Using Electromagnetic Emanations\", in David\r\n Aucsmith, ed., \"Information Hiding, Second International\r\n Workshop, IH'98\", Portland, Oregon, USA, 15-17 April 1998,\r\n LNCS 1525, Springer-Verlag, ISBN 3-540-65386-4, pp. 124-142.\r\n [Land] Landwehr, C., \"Formal Models for Computer Security\", in \"ACM\r\n Computing Surveys\", vol. 13, no. 3, September 1981, pp. 247-\r\n 278.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 418 of 436\n\n[Larm] Larmouth, J., \"ASN.1 Complete\", Open System Solutions, 1999\r\n (a freeware book).\r\n [M0404] U.S. Office of Management and Budget, \"E-Authentication\r\n Guidance for Federal Agencies\", Memorandum M-04-04, 16\r\n December 2003.\r\n [Mene] Menezes, A. et al, \"Some Key Agreement Protocols Providing\r\n Implicit Authentication\", in \"The 2nd Workshop on Selected\r\n Areas in Cryptography\", 1995.\r\nShirey Informational [Page 351]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [Moor] Moore, A. et al, \"Attack Modeling for Information Security\r\n and Survivability\", Carnegie Mellon University / Software\r\n Engineering Institute, CMU/SEI-2001-TN-001, March 2001.\r\n [Murr] Murray, W., \"Courtney's Laws of Security\", in \"Infosecurity\r\n News\", March/April 1993, p. 65.\r\n [N4001] National Security Telecommunications and Information System\r\n Security Committee, \"Controlled Cryptographic Items\",\r\n NSTISSI No. 4001, 25 March 1985.\r\n [N4006] ---, \"Controlled Cryptographic Items\", NSTISSI No. 4006, 2\r\n December 1991.\r\n [N7003] ---, \"Protective Distribution Systems\", NSTISSI No. 7003, 13\r\n December 1996.\r\n [NCS01] National Computer Security Center, \"A Guide to Understanding\r\n Audit in Trusted Systems\", NCSC-TG-001, 1 June 1988. (See:\r\n Rainbow Series.)\r\n [NCS03] ---, \"Information System Security Policy Guideline\", I942-\r\n TR-003, version 1, July 1994. (See: Rainbow Series.)\r\n [NCS04] ---, \"Glossary of Computer Security Terms\", NCSC-TG-004,\r\n version 1, 21 October 1988. (See: Rainbow Series.)\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 419 of 436\n\n[NCS05] ---, \"Trusted Network Interpretation of the Trusted Computer\r\n System Evaluation Criteria\", NCSC-TG-005, version 1, 31 July\r\n 1987. (See: Rainbow Series.)\r\n [NCS25] ---, \"A Guide to Understanding Data Remanence in Automated\r\n Information Systems\", NCSC-TG-025, version 2, September\r\n 1991. (See: Rainbow Series.)\r\n [NCSSG] National Computer Security Center, \"COMPUSECese: Computer\r\n Security Glossary\", NCSC-WA-001-85, Edition 1, 1 October\r\n 1985. (See: Rainbow Series.)\r\n [NRC91] National Research Council, \"Computers At Risk: Safe\r\n Computing in the Information Age\", National Academy Press,\r\n 1991.\r\n [NRC98] Schneider, F., ed., \"Trust in Cyberspace\", National Research\r\n Council, National Academy of Sciences, 1998.\r\n [Padl] Padlipsky, M., \"The Elements of Networking Style\", 1985,\r\n ISBN 0-13-268111-0.\r\nShirey Informational [Page 352]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [PAG] American Bar Association, \"PKI Assessment Guidelines\",\r\n version 1.0, 10 May 2002. (See: [DSG].)\r\n [Park] Parker, D., \"Computer Security Management\", ISBN 0-8359-\r\n 0905-0, 1981\r\n [Perr] Perrine, T. et al, \"An Overview of the Kernelized Secure\r\n Operating System (KSOS)\", in \"Proceedings of the 7th DoD/NBS\r\n Computer Security Conference\", 24-26 September 1984.\r\n [PGP] Garfinkel, S.. \"PGP: Pretty Good Privacy\", O'Reilly \u0026\r\n Associates, Inc., Sebastopol, CA, 1995.\r\n [PKCS] Kaliski Jr., B., \"An Overview of the PKCS Standards\", RSA\r\n Data Security, Inc., 3 June 1991.\r\n [PKC05] RSA Laboratories, \"PKCS #5: Password-Based Encryption\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 420 of 436\n\nStandard \", version 1.5, 1 November 1993. (See: RFC 2898.)\r\n [PKC07] ---, \"PKCS #7: Cryptographic Message Syntax Standard\",\r\n version 1.5, 1 November 1993. (See: RFC 2315.)\r\n [PKC10] ---, \"PKCS #10: Certification Request Syntax Standard\",\r\n version 1.0, 1 November 1993.\r\n [PKC11] ---, \"PKCS #11: Cryptographic Token Interface Standard\",\r\n version 1.0, 28 April 1995.\r\n [PKC12] ---, \"PKCS #12: Personal Information Exchange Syntax\",\r\n version 1.0, 24 June 1995.\r\n [R1108] Kent, S., \"U.S. Department of Defense Security Options for\r\n the Internet Protocol\", RFC 1108, November 1991.\r\n [R1135] Reynolds, J., \"The Helminthiasis of the Internet\", RFC 1135,\r\n December 1989\r\n [R1208] Jacobsen, O. and D. Lynch, \"A Glossary of Networking Terms\",\r\n RFC 1208, March 1991.\r\n [R1281] Pethia, R., Crocker, S., and B. Fraser, \"Guidelines for\r\n Secure Operation of the Internet\", RFC 1281, November 1991.\r\n [R1319] Kaliski, B., \"The MD2 Message-Digest Algorithm\", RFC 1319,\r\n April 1992.\r\n [R1320] Rivest, R., \"The MD4 Message-Digest Algorithm\", RFC 1320,\r\n April 1992.\r\nShirey Informational [Page 353]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [R1321] ---, \"The MD5 Message-Digest Algorithm\", RFC 1321, April\r\n 1992.\r\n [R1334] Lloyd, B. and W. Simpson, \"PPP Authentication Protocols\",\r\n RFC 1334, October 1992.\r\n [R1413] St. Johns, M., \"Identification Protocol\", RFC 1413, February\r\n 1993.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 421 of 436\n\n[R1421] Linn, J., \"Privacy Enhancement for Internet Electronic Mail,\r\n Part I: Message Encryption and Authentication Procedures\",\r\n RFC 1421, February 1993.\r\n [R1422] Kent, S., \"Privacy Enhancement for Internet Electronic Mail,\r\n Part II: Certificate-Based Key Management\", RFC 1422,\r\n February 1993.\r\n [R1455] Eastlake 3rd, D., \"Physical Link Security Type of Service\",\r\n RFC 1455, May 1993.\r\n [R1457] Housley, R., \"Security Label Framework for the Internet\",\r\n RFC 1457, May 1993.\r\n [R1492] Finseth, C., \"An Access Control Protocol, Sometimes Called\r\n TACACS\", RFC 1492, July 1993.\r\n [R1507] Kaufman, C., \"DASS: Distributed Authentication Security\r\n Service\", RFC 1507, September 1993.\r\n [R1731] Myers, J., \"IMAP4 Authentication Mechanisms\", RFC 1731,\r\n December 1994.\r\n [R1734] ---, \"POP3 AUTHentication Command\", RFC 1734, Dec, 1994.\r\n [R1760] Haller, N., \"The S/KEY One-Time Password System\", RFC 1760,\r\n February 1995.\r\n [R1824] Danisch, H., \"The Exponential Security System TESS: An\r\n Identity-Based Cryptographic Protocol for Authenticated Key-\r\n Exchange (E.I.S.S.-Report 1995/4)\", RFC 1824, August 1995.\r\n [R1828] Metzger, P. and W. Simpson, \"IP Authentication using Keyed\r\n MD5\", RFC 1828, August 1995.\r\n [R1829] Karn, P., Metzger, P., and W. Simpson, \"The ESP DES-CBC\r\n Transform\", RFC 1829, August 1995.\r\nShirey Informational [Page 354]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 422 of 436\n\n[R1848] Crocker, S., Freed, N., Galvin, J., and S. Murphy, \"MIME\r\n Object Security Services\", RFC 1848, October 1995.\r\n [R1851] Karn, P., Metzger, P., and W. Simpson, \"The ESP Triple DES\r\n Transform\", RFC 1851, September 1995.\r\n [R1928] Leech, M., Ganis, M., Lee, Y., Kuris, R., Koblas, D., and L.\r\n Jones, \"SOCKS Protocol Version 5\", RFC 1928, March 1996.\r\n [R1958] Carpenter, B., \"Architectural Principles of the Internet\",\r\n RFC 1958, June 1996.\r\n [R1983] Malkin, G., \"Internet Users' Glossary\", FYI 18, RFC 1983,\r\n August 1996.\r\n [R1994] Simpson, W., \"PPP Challenge Handshake Authentication\r\n Protocol (CHAP)\", RFC 1994, August 1996.\r\n [R2078] Linn, J., \"Generic Security Service Application Program\r\n Interface, Version 2\", RFC 2078, January 1997. (Superseded\r\n by RFC 2743.)\r\n [R2084] Bossert, G., Cooper, S., and W. Drummond, \"Considerations\r\n for Web Transaction Security\", RFC 2084, January 1997.\r\n [R2104] Krawczyk, H., Bellare, M., and R. Canetti, \"HMAC: Keyed-\r\n Hashing for Message Authentication\", RFC 2104, February\r\n 1997.\r\n [R2144] Adams, C., \"The CAST-128 Encryption Algorithm\", RFC 2144,\r\n May 1997.\r\n [R2179] Gwinn, A., \"Network Security For Trade Shows\", RFC 2179,\r\n July 1997.\r\n [R2195] Klensin, J., Catoe, R., and P. Krumviede, \"IMAP/POP\r\n AUTHorize Extension for Simple Challenge/Response\", RFC\r\n 2195, September 1997.\r\n [R2196] Fraser, B., \"Site Security Handbook\", FYI 8, RFC 2196,\r\n September 1997.\r\n [R2202] Cheng, P. and R. Glenn, \"Test Cases for HMAC-MD5 and HMAC-\r\n SHA-1\", RFC 2202, Sep. 1997.\r\n [R2222] Myers, J., \"Simple Authentication and Security Layer\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 423 of 436\n\n(SASL)\", RFC 2222, October 1997.\r\nShirey Informational [Page 355]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [R2289] Haller, N., Metz, C., Nesser, P., and M. Straw, \"A One-Time\r\n Password System\", STD 61, RFC 2289, February 1998.\r\n [R2323] Ramos, A., \"IETF Identification and Security Guidelines\",\r\n RFC 2323, 1 April 1998. (Intended for humorous entertainment\r\n -- \"please laugh loud and hard\" -- and does not contain\r\n serious security information.)\r\n [R2350] Brownlee, N. and E. Guttman, \"Expectations for Computer\r\n Security Incident Response\", BCP 21, RFC 2350, June 1998.\r\n [R2356] Montenegro, G. and V. Gupta, \"Sun's SKIP Firewall Traversal\r\n for Mobile IP\", RFC 2356, June 1998.\r\n [R2401] Kent, S. and R. Atkinson, \"Security Architecture for the\r\n Internet Protocol\", RFC 2401, November 1998.\r\n [R2402] ---, \"IP Authentication Header\", RFC 2402, November 1998.\r\n [R2403] Madson, C. and R. Glenn, \"The Use of HMAC-MD5-96 within ESP\r\n and AH\", RFC 2403, November 1998.\r\n [R2404] ---, \"The Use of HMAC-SHA-1-96 within ESP and AH\", RFC 2404,\r\n November 1998.\r\n [R2405] Madson, C. and N. Doraswamy, \"The ESP DES-CBC Cipher\r\n Algorithm With Explicit IV\", RFC 2405, November 1998.\r\n [R2406] Kent, S. and R. Atkinson, \"IP Encapsulating Security Payload\r\n (ESP)\", RFC 2406, November 1998.\r\n [R2407] Piper, D. \"The Internet IP Security Domain of Interpretation\r\n for ISAKMP\", RFC 2407, November 1998.\r\n [R2408] Maughan, D., Schertler, M., Schneider, M., and J. Turner,\r\n \"Internet Security Association and Key Management Protocol\r\n (ISAKMP)\", RFC 2408, November 1998.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 424 of 436\n\n[R2410] Glenn, R. and S. Kent, \"The NULL Encryption Algorithm and\r\n Its Use With IPsec\", RFC 2410, November 1998.\r\n [R2412] Orman, H., \"The OAKLEY Key Determination Protocol\", RFC\r\n 2412, November 1998.\r\n [R2451] Pereira, R. and R. Adams, \"The ESP CBC-Mode Cipher\r\n Algorithms\", RFC 2451, November 1998.\r\nShirey Informational [Page 356]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [R2504] Guttman, E., Leong, L., and G. Malkin, \"Users' Security\r\n Handbook\", RFC 2504, February 1999.\r\n [R2560] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C.\r\n Adams, \"X.509 Internet Public Key Infrastructure Online\r\n Certificate Status Protocol - OCSP\", RFC 2560, June 1999.\r\n [R2612] Adams, C. and J. Gilchrist, \"The CAST-256 Encryption\r\n Algorithm\", RFC 2612, June 1999.\r\n [R2628] Smyslov, V., \"Simple Cryptographic Program Interface (Crypto\r\n API)\", RFC 2628, June 1999.\r\n [R2631] Rescorla, E., \"Diffie-Hellman Key Agreement Method\", RFC\r\n 2631, June 1999. (See: Diffie-Hellman-Merkle.)\r\n [R2634] Hoffman, P., \"Enhanced Security Services for S/MIME\", RFC\r\n 2634, June 1999.\r\n [R2635] Hambridge, S. and A. Lunde, \"DON'T SPEW: A Set of Guidelines\r\n for Mass Unsolicited Mailings and Postings\", RFC 2635, June\r\n 1999.\r\n [R2660] Rescorla, E. and A. Schiffman, \"The Secure HyperText\r\n Transfer Protocol\", RFC 2660, August 1999.\r\n [R2743] Linn, J., \"Generic Security Service Application Program\r\n Interface Version 2, Update 1\", RFC 2743, January 2000.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 425 of 436\n\n[R2773] Housley, R., Yee, P., and W. Nace, \"Encryption using KEA and\r\n SKIPJACK\", RFC 2773, February 2000.\r\n [R2801] Burdett, D., \"Internet Open Trading Protocol - IOTP, Version\r\n 1.0\", RFC 2801, April 2000.\r\n [R2827] Ferguson, P. and D. Senie, \"Network Ingress Filtering:\r\n Defeating Denial of Service Attacks which employ IP Source\r\n Address Spoofing\", BCP 38, RFC 2827, May 2000.\r\n [R2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, \"Remote\r\n Authentication Dial In User Service (RADIUS)\", RFC 2865,\r\n June 2000.\r\n [R3060] Moore, B., Ellesson, E., Strassner, J., and A. Westerinen,\r\n \"Policy Core Information Model -- Version 1 Specification\",\r\n RFC 3060, February 2001.\r\nShirey Informational [Page 357]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [R3198] Westerinen, A., Schnizlein, J., Strassner, J., Scherling,\r\n M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry,\r\n J., and S. Waldbusser, \"Terminology for Policy-Based\r\n Management\", RFC 3198, November 2001.\r\n [R3280] Housley, R., Polk, W., Ford, W., and D. Solo, \"Internet\r\n X.509 Public Key Infrastructure Certificate and Certificate\r\n Revocation List (CRL) Profile\", RFC 3280, April 2002.\r\n [R3547] Baugher, M., Weis, B., Hardjono, T., and H. Harney, \"Group\r\n Domain of Interpretation\", RFC 3547, July 2003.\r\n [R3552] Rescorla, E. and B. Korver, \"Guidelines for Writing RFC Text\r\n on Security Considerations\", RFC 3552, July 2003.\r\n [R3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S. Wu,\r\n \"Internet X.509 Public Key Infrastructure Certificate Policy\r\n and Certification Practices Framework\", RFC 3647, November\r\n 2003.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 426 of 436\n\n[R3739] Santesson, S., Nystrom, M., and T. Polk, \"Internet X.509\r\n Public Key Infrastructure: Qualified Certificates Profile\",\r\n RFC 3739, March 2004.\r\n [R3740] Hardjono, T. and B. Weis, \"The Multicast Group Security\r\n Architecture\", RFC 3740, March 2004.\r\n [R3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.\r\n Levkowetz, \"Extensible Authentication Protocol (EAP)\", RFC\r\n 3748, June 2004.\r\n [R3766] Orman, H. and P. Hoffman, \"Determining Strengths For Public\r\n Keys Used For Exchanging Symmetric Keys\", BCP 86, RFC 3766,\r\n April 2004.\r\n [R3820] Tuecke, S., Welch, V., Engert, D., Pearlman, L., and M.\r\n Thompson, \"Internet X.509 Public Key Infrastructure (PKI)\r\n Proxy Certificate Profile\", RFC 3820, June 2004.\r\n [R3851] Ramsdell, B., \"Secure/Multipurpose Internet Mail Extensions\r\n (S/MIME) Version 3.1 Message Specification\", RFC 3851, July\r\n 2004.\r\n [R3871] Jones, G., \"Operational Security Requirements for Large\r\n Internet Service Provider (ISP) IP Network Infrastructure\",\r\n RFC 3871, September 2004.\r\nShirey Informational [Page 358]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [R4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.\r\n Rose, \"DNS Security Introduction and Requirements\", RFC\r\n 4033, March 2005.\r\n [R4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.\r\n Rose, \"Resource Records for the DNS Security Extensions\",\r\n RFC 4034, March 2005.\r\n [R4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.\r\n Rose, \"Protocol Modifications for the DNS Security\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 427 of 436\n\nExtensions\", RFC 4035, March 2005.\r\n [R4086] Eastlake, D., 3rd, Schiller, J., and S. Crocker, \"Randomness\r\n Requirements for Security\", BCP 106, RFC 4086, June 2005.\r\n [R4120] Neuman, C., Yu, T., Hartman, S., and K. Raeburn, \"The\r\n Kerberos Network Authentication Service (V5)\", RFC 4120,\r\n July 2005.\r\n [R4158] Cooper, M., Dzambasow, Y., Hesse, P., Joseph, S., and R.\r\n Nicholas, \"Internet X.509 Public Key Infrastructure:\r\n Certification Path Building\", RFC 4158, September 2005.\r\n [R4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, \"Internet\r\n X.509 Public Key Infrastructure Certificate Management\r\n Protocol (CMP)\", RFC 4210, September 2005.\r\n [R4301] Kent, S. and K. Seo, \"Security Architecture for the Internet\r\n Protocol\", RFC 4301, December 2005.\r\n [R4302] Kent, S., \"IP Authentication Header\", RFC 4302, December\r\n 2005.\r\n [R4303] Kent, S., \"IP Encapsulating Security Payload (ESP)\", RFC\r\n 4303, December 2005.\r\n [R4306] Kaufman, C., \"Internet Key Exchange (IKEv2) Protocol\", RFC\r\n 4306, December 2005.\r\n [R4346] Dierks, T. and E. Rescorla, \"The Transport Layer Security\r\n (TLS) Protocol Version 1.1\", RFC 4346, April 2006.\r\n [R4422] Melnikov, A. and K. Zeilenga, \"Simple Authentication and\r\n Security Layer (SASL)\", RFC 4422, June 2006.\r\nShirey Informational [Page 359]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [Raym] Raymond, E., ed., \"The On-Line Hacker Jargon File\", version\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 428 of 436\n\n4.0.0, 24 July 1996. (See: http://www.catb.org/~esr/jargon\r\n for the latest version. Also, \"The New Hacker's Dictionary\",\r\n 3rd edition, MIT Press, September 1996, ISBN 0-262-68092-0.)\r\n [Roge] Rogers, H., \"An Overview of the CANEWARE Program\", in\r\n \"Proceedings of the 10th National Computer Security\r\n Conference\", NIST and NCSC, September 1987.\r\n [RSA78] Rivest, R., A. Shamir, and L. Adleman, \"A Method for\r\n Obtaining Digital Signatures and Public-Key Cryptosystems\",\r\n in \"Communications of the ACM\", vol. 21, no. 2, February\r\n 1978, pp. 120-126.\r\n [RSCG] NSA, \"Router Security Configuration Guide: Principles and\r\n Guidance for Secure Configuration of IP Routers, with\r\n Detailed Instructions for Cisco Systems Routers\", version\r\n 1.1c, C4-040R-02, 15 December 2005, available at\r\n http://www.nsa.gov/snac/routers/C4-040R-02.pdf.\r\n [Russ] Russell, D. et al, Chapter 10 (\"TEMPEST\") of \"Computer\r\n Security Basics\", ISBN 0-937175-71-4, 1991.\r\n [SAML] Organization for the Advancement of Structured Information\r\n Standards (OASIS), \"Assertions and Protocol for the OASIS\r\n Security Assertion Markup Language (SAML)\", version 1.1, 2\r\n September 2003.\r\n [Sand] Sandhu, R. et al, \"Role-Based Access Control Models\", in\r\n \"IEEE Computer\", vol. 29, no. 2, February 1996, pp. 38-47.\r\n [Schn] Schneier, B., \"Applied Cryptography Second Edition\", John\r\n Wiley \u0026 Sons, Inc., New York, 1996.\r\n [SDNS3] U.S. DoD, NSA, \"Secure Data Network Systems, Security\r\n Protocol 3 (SP3)\", document SDN.301, Revision 1.5, 15 May\r\n 1989.\r\n [SDNS4] ---, \"Secure Data Network Systems, Security Protocol 4\r\n (SP4)\", document SDN.401, Revision 1.2, 12 July 1988.\r\n [SDNS7] ---, \"Secure Data Network Systems, Message Security Protocol\r\n (MSP)\", SDN.701, Revision 4.0, 7 June 1996, with\r\n \"Corrections to Message Security Protocol, SDN.701, Rev 4.0,\r\n 96-06-07\", 30 Aug, 1996.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 429 of 436\n\nShirey Informational [Page 360]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [SET1] MasterCard and Visa, \"SET Secure Electronic Transaction\r\n Specification, Book 1: Business Description\", version 1.0,\r\n 31 May 1997.\r\n [SET2] ---, \"SET Secure Electronic Transaction Specification, Book\r\n 2: Programmer's Guide\", version 1.0, 31 May 1997.\r\n [SKEME] Krawczyk, H., \"SKEME: A Versatile Secure Key Exchange\r\n Mechanism for Internet\", in \"Proceedings of the 1996\r\n Symposium on Network and Distributed Systems Security\".\r\n [SKIP] \"SKIPJACK and KEA Algorithm Specifications\", version 2.0, 22\r\n May 1998, and \"Clarification to the SKIPJACK Algorithm\r\n Specification\", 9 May 2002 (available from NIST Computer\r\n Security Resource Center).\r\n [SP12] NIST, \"An Introduction to Computer Security: The NIST\r\n Handbook\", Special Publication 800-12.\r\n [SP14] Swanson, M. et al (NIST), \"Generally Accepted Principles and\r\n Practices for Security Information Technology Systems\",\r\n Special Publication 800-14, September 1996.\r\n [SP15] Burr, W. et al (NIST), \"Minimum Interoperability\r\n Specification for PKI Components (MISPC), Version 1\",\r\n Special Publication 800-15, September 1997.\r\n [SP22] Rukhin, A. et al (NIST), \"A Statistical Test Suite for\r\n Random and Pseudorandom Number Generators for Cryptographic\r\n Applications\", Special Publication 800-15, 15 May 2001.\r\n [SP27] Stoneburner, G. et al (NIST), \"Engineering Principles for\r\n Information Technology Security (A Baseline for Achieving\r\n Security)\", Special Publication 800-27 Rev A, June 2004.\r\n [SP28] Jansen, W. (NIST), \"Guidelines on Active Content and Mobile\r\n Code\", Special Publication 800-28, October 2001.\r\n [SP30] Stoneburner, G. et al (NIST), \"Risk Management Guide for\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 430 of 436\n\nInformation Technology Systems\", Special Publication 800-30,\r\n October 2001.\r\n [SP31] Bace, R. et al (NIST), \"Intrusion Detection Systems\",\r\n Special Publication 800-31.\r\n [SP32] Kuhn, D. (NIST), \"Introduction to Public Key Technology and\r\n the Federal PKI Infrastructure \", Special Publication\r\n 800-32, 26 February 2001.\r\nShirey Informational [Page 361]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [SP33] Stoneburner, G. (NIST), \"Underlying Technical Models for\r\n Information Technology Security\", Special Publication\r\n 800-33, December 2001.\r\n [SP37] Ross, R. et al (NIST), \"Guide for the Security Certification\r\n and Accreditation of Federal Information Systems\", Special\r\n Publication 800-37, May 2004.\r\n [SP38A] Dworkin, M. (NIST), \"Recommendation for Block Cipher Modes\r\n of Operation: Methods and Techniques\", Special Publication\r\n 800-38A, 2001 Edition, December 2001.\r\n [SP38B] ---, \"Recommendation for Block Cipher Modes of Operation:\r\n The CMAC Mode for Authentication\", Special Publication\r\n 800-38B, May 2005.\r\n [SP38C] ---, \"Recommendation for Block Cipher Modes of Operation:\r\n The CCM Mode for Authentication and Confidentiality\",\r\n Special Publication 800-38C, May 2004.\r\n [SP41] Wack, J. et al (NIST), \"Guidelines on Firewalls and Firewall\r\n Policy\", Special Publication 800-41, January 2002.\r\n [SP42] ---, \"Guideline on Network Security Testing\", Special\r\n Publication 800-42, October 2003.\r\n [SP56] NIST, \"Recommendations on Key Establishment Schemes\", Draft\r\n 2.0, Special Publication 800-63, January 2003.\r\n [SP57] ---, \"Recommendation for Key Management\", Part 1 \"General\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 431 of 436\n\nGuideline\" and Part 2 \"Best Practices for Key Management\r\n Organization\", Special Publication 800-57, DRAFT, January\r\n 2003.\r\n [SP61] Grance, T. et al (NIST), \"Computer Security Incident\r\n Handling Guide\", Special Publication 800-57, January 2003.\r\n [SP63] Burr, W. et al (NIST), \"Electronic Authentication\r\n Guideline\", Special Publication 800-63, June 2004\r\n [SP67] Barker, W. (NIST), \"Recommendation for the Triple Data\r\n Encryption Algorithm (TDEA) Block Cipher\", Special\r\n Publication 800-67, May 2004\r\n [Stal] Stallings, W., \"Local Networks\", 1987, ISBN 0-02-415520-9.\r\nShirey Informational [Page 362]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [Stei] Steiner, J. et al, \"Kerberos: An Authentication Service for\r\n Open Network Systems\", in \"Usenix Conference Proceedings\",\r\n February 1988.\r\n [Weis] Weissman, C., \"Blacker: Security for the DDN: Examples of A1\r\n Security Engineering Trades\", in \"Symposium on Security and\r\n Privacy\", IEEE Computer Society Press, May 1992, pp. 286-\r\n 292.\r\n [X400] International Telecommunications Union -- Telecommunication\r\n Standardization Sector (formerly \"CCITT\"), Recommendation\r\n X.400, \"Message Handling Services: Message Handling System\r\n and Service Overview\".\r\n [X419] ---, \"Message Handling Systems: Protocol Specifications\",\r\n ITU-T Recommendation X.419. (Equivalent to ISO 10021-6).\r\n [X420] ---, \"Message Handling Systems: Interpersonal Messaging\r\n System\", ITU-T Recommendation X.420. (Equivalent to ISO\r\n 10021-7.).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 432 of 436\n\n[X500] ---, Recommendation X.500, \"Information Technology -- Open\r\n Systems Interconnection -- The Directory: Overview of\r\n Concepts, Models, and Services\". (Equivalent to ISO 9594-1.)\r\n [X501] ---, Recommendation X.501, \"Information Technology -- Open\r\n Systems Interconnection -- The Directory: Models\".\r\n [X509] ---, Recommendation X.509, \"Information Technology -- Open\r\n Systems Interconnection -- The Directory: Authentication\r\n Framework\", COM 7-250-E Revision 1, 23 February 2001.\r\n (Equivalent to ISO 9594-8.)\r\n [X519] ---, Recommendation X.519, \"Information Technology -- Open\r\n Systems Interconnection -- The Directory: Protocol\r\n Specifications\".\r\n [X520] ---, Recommendation X.520, \"Information Technology -- Open\r\n Systems Interconnection -- The Directory: Selected Attribute\r\n Types\".\r\n [X680] ---, Recommendation X.680, \"Information Technology --\r\n Abstract Syntax Notation One (ASN.1) -- Specification of\r\n Basic Notation\", 15 November 1994. (Equivalent to ISO/IEC\r\n 8824-1.)\r\nShirey Informational [Page 363]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\n [X690] ---, Recommendation X.690, \"Information Technology -- ASN.1\r\n Encoding Rules -- Specification of Basic Encoding Rules\r\n (BER), Canonical Encoding Rules (CER) and Distinguished\r\n Encoding Rules (DER)\", 15 November 1994. (Equivalent to\r\n ISO/IEC 8825-1.)\r\n7. Acknowledgments\r\n George Huff had a good idea! [Huff]\r\nAuthor's Address\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 433 of 436\n\nDr. Robert W. Shirey\r\n 3516 N. Kensington St.\r\n Arlington, Virginia 22207-1328\r\n USA\r\n EMail: rwshirey4949@verizon.net\r\nShirey Informational [Page 364]\r\nRFC 4949 Internet Security Glossary, Version 2 August 2007\r\nFull Copyright Statement\r\n Copyright (C) The IETF Trust (2007).\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 434 of 436\n\nThis document is subject to the rights, licenses and restrictions\r\n contained in BCP 78 and at www.rfc-editor.org/copyright.html, and\r\n except as set forth therein, the authors retain all their rights.\r\n This document and the information contained herein are provided on an\r\n \"AS IS\" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS\r\n OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND\r\n THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS\r\n OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF\r\n THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED\r\n WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.\r\nIntellectual Property\r\n The IETF takes no position regarding the validity or scope of any\r\n Intellectual Property Rights or other rights that might be claimed to\r\n pertain to the implementation or use of the technology described in\r\n this document or the extent to which any license under such rights\r\n might or might not be available; nor does it represent that it has\r\n made any independent effort to identify any such rights. Information\r\n on the procedures with respect to rights in RFC documents can be\r\n found in BCP 78 and BCP 79.\r\n Copies of IPR disclosures made to the IETF Secretariat and any\r\n assurances of licenses to be made available, or the result of an\r\n attempt made to obtain a general license or permission for the use of\r\n such proprietary rights by implementers or users of this\r\n specification can be obtained from the IETF on-line IPR repository at\r\n http://www.ietf.org/ipr.\r\n The IETF invites any interested party to bring to its attention any\r\n copyrights, patents or patent applications, or other proprietary\r\n rights that may cover technology that may be required to implement\r\n this standard. Please address the information to the IETF at\r\n ietf-ipr@ietf.org.\r\nAcknowledgement\r\n Funding for the RFC Editor function is currently provided by the\r\n Internet Society.\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 435 of 436\n\nShirey Informational [Page 365]\r\nSource: https://www.ietf.org/rfc/rfc4949.txt\r\nhttps://www.ietf.org/rfc/rfc4949.txt\r\nPage 436 of 436\n\nCompare: reflection Shirey attack, replay Informational attack.)  [Page 23]\nRFC 4949 Internet Security Glossary, Version 2 August 2007\nThe term \"attack\" relates to some other basic security terms as\nshown in the following diagram:   \n+------- -----+ +- ---+ +- ------ ----+\n| An Attack: | |Counter- | | A System Resource: |\n| i.e., A Threat Action | | measure | | Target of the Attack |\n| +----------+ | | | | +-----------------+  |\n| | Attacker |\u003c==================||\u003c=========    | |\n| | i.e., | Passive | | | | | Vulnerability | |\n| | A Threat |\u003c=================\u003e||\u003c========\u003e    | |\n| | Agent | or Active | | | | +-------|||-------+  |\n| +----------+ Attack | | | | VVV |\n| | | | | Threat Consequences |\n+------- -----+ +- ---+ +- ------ ----+\n$ attack potential    \n(I) The perceived likelihood of success should an attack be\n  Page 28 of 436 \n\nrelated variations: Shirey encipherment, Informational decipher, decipherment). [Page 119]\nRFC 4949 Internet Security Glossary, Version 2 August 2007\n  Page 142 of 436  \n\n(See: principal, Shirey role-based Informational access control.) [Page 147]\nRFC 4949 Internet Security Glossary, Version 2 August 2007\nWhen an identity of a user is being registered in a system, the\nsystem may require presentation of evidence that proves the \nidentity's authenticity (i.e., that the user has the right to\nclaim or use the identity) and its eligibility (i.e., that the\nidentity is qualified to be registered and needs to be \nregistered).    \nThe following diagram illustrates how this term relates to some\nother terms in a PKI system: authentication information, \nidentifier, identifier credential, registration, registered user,\nsubscriber, and user.   \nRelationships: === one-to-one, ==\u003e one-to-many, \u003c=\u003e many-to-many. \n +------ --------- ------- ----+\n | PKI System  |\n+---- + | +------------------+ +-------------------------+  |\n| User, | | |Subscriber, i.e., | | Identity of Subscriber | |\n|i.e., one| | | Registered User, | | is system-unique | |\n| of the | | | is system-unique | | +---------------------+  | |\n|following| | | +--------------+ | | | Subscriber | | |\n| | | | | User's core | | | | Identity's | | |\n| +-----+ |===| | Registration | |==\u003e| | Registration data | | |\n| |human| | | | | data, i.e., | | | |+-------------------+|  | |\n| |being| | | | | an entity's | | | || same core data || | |\n| +-----+ | | | |distinguishing|========|for  all Identities || | |\n| or | | | | attribute | | | || of the same User || | |\n| +-----+ | | | | values | | +===|+-------------------+|  | |\n| |auto-| | | | +--------------+ | | | +---------------------+  | |\n| |mated| | | +------------------+ | +------------|------------+  |\n  Page 176 of 436 \n\nrequire protection Shirey against unauthorized Informational disclosure. [C4009] [Page 197]\nRFC 4949 Internet Security Glossary, Version 2 August 2007\n$ national security system   \n(O) /U.S. Government/ Any Government-operated  information system\n  Page 235 of 436",
	"extraction_quality": 1,
	"language": "EN",
	"sources": [
		"MITRE"
	],
	"references": [
		"https://www.ietf.org/rfc/rfc4949.txt"
	],
	"report_names": [
		"rfc4949.txt"
	],
	"threat_actors": [
		{
			"id": "b740943a-da51-4133-855b-df29822531ea",
			"created_at": "2022-10-25T15:50:23.604126Z",
			"updated_at": "2026-04-10T02:00:05.259593Z",
			"deleted_at": null,
			"main_name": "Equation",
			"aliases": [
				"Equation"
			],
			"source_name": "MITRE:Equation",
			"tools": null,
			"source_id": "MITRE",
			"reports": null
		},
		{
			"id": "cf7fc640-acfe-41c4-9f3d-5515d53a3ffb",
			"created_at": "2023-01-06T13:46:38.228042Z",
			"updated_at": "2026-04-10T02:00:02.883048Z",
			"deleted_at": null,
			"main_name": "APT1",
			"aliases": [
				"PLA Unit 61398",
				"Comment Crew",
				"Byzantine Candor",
				"Comment Group",
				"GIF89a",
				"Group 3",
				"TG-8223",
				"Brown Fox",
				"ShadyRAT",
				"G0006",
				"COMMENT PANDA"
			],
			"source_name": "MISPGALAXY:APT1",
			"tools": [],
			"source_id": "MISPGALAXY",
			"reports": null
		},
		{
			"id": "f4f16213-7a22-4527-aecb-b964c64c2c46",
			"created_at": "2024-06-19T02:03:08.090932Z",
			"updated_at": "2026-04-10T02:00:03.6289Z",
			"deleted_at": null,
			"main_name": "GOLD NIAGARA",
			"aliases": [
				"Calcium ",
				"Carbanak",
				"Carbon Spider ",
				"FIN7 ",
				"Navigator ",
				"Sangria Tempest ",
				"TelePort Crew "
			],
			"source_name": "Secureworks:GOLD NIAGARA",
			"tools": [
				"Bateleur",
				"Carbanak",
				"Cobalt Strike",
				"DICELOADER",
				"DRIFTPIN",
				"GGLDR",
				"GRIFFON",
				"JSSLoader",
				"Meterpreter",
				"OFFTRACK",
				"PILLOWMINT",
				"POWERTRASH",
				"SUPERSOFT",
				"TAKEOUT",
				"TinyMet"
			],
			"source_id": "Secureworks",
			"reports": null
		},
		{
			"id": "3aaf0755-5c9b-4612-9f0e-e266ef1bdb4b",
			"created_at": "2022-10-25T16:07:23.480196Z",
			"updated_at": "2026-04-10T02:00:04.626125Z",
			"deleted_at": null,
			"main_name": "Comment Crew",
			"aliases": [
				"APT 1",
				"BrownFox",
				"Byzantine Candor",
				"Byzantine Hades",
				"Comment Crew",
				"Comment Panda",
				"G0006",
				"GIF89a",
				"Group 3",
				"Operation Oceansalt",
				"Operation Seasalt",
				"Operation Siesta",
				"Shanghai Group",
				"TG-8223"
			],
			"source_name": "ETDA:Comment Crew",
			"tools": [
				"Auriga",
				"Cachedump",
				"Chymine",
				"CookieBag",
				"Darkmoon",
				"GDOCUPLOAD",
				"GLOOXMAIL",
				"GREENCAT",
				"Gen:Trojan.Heur.PT",
				"GetMail",
				"Hackfase",
				"Hacksfase",
				"Helauto",
				"Kurton",
				"LETSGO",
				"LIGHTBOLT",
				"LIGHTDART",
				"LOLBAS",
				"LOLBins",
				"LONGRUN",
				"Living off the Land",
				"Lslsass",
				"MAPIget",
				"ManItsMe",
				"Mimikatz",
				"MiniASP",
				"Oceansalt",
				"Pass-The-Hash Toolkit",
				"Poison Ivy",
				"ProcDump",
				"Riodrv",
				"SPIVY",
				"Seasalt",
				"ShadyRAT",
				"StarsyPound",
				"TROJAN.COOKIES",
				"TROJAN.FOXY",
				"TabMsgSQL",
				"Tarsip",
				"Trojan.GTALK",
				"WebC2",
				"WebC2-AdSpace",
				"WebC2-Ausov",
				"WebC2-Bolid",
				"WebC2-Cson",
				"WebC2-DIV",
				"WebC2-GreenCat",
				"WebC2-Head",
				"WebC2-Kt3",
				"WebC2-Qbp",
				"WebC2-Rave",
				"WebC2-Table",
				"WebC2-UGX",
				"WebC2-Yahoo",
				"Wordpress Bruteforcer",
				"bangat",
				"gsecdump",
				"pivy",
				"poisonivy",
				"pwdump",
				"zxdosml"
			],
			"source_id": "ETDA",
			"reports": null
		}
	],
	"ts_created_at": 1775434634,
	"ts_updated_at": 1775792289,
	"ts_creation_date": 0,
	"ts_modification_date": 0,
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