Internet Security Glossary, Version 2

$ name

(I) Synonym for "identifier".

$ naming authority

(O) /U.S. DoD/ An organizational entity responsible for assigning DNs and for assuring that each DN is meaningful and unique within its domain. [DoD9]

$ National Computer Security Center (NCSC)

(O) A U.S. DoD organization, housed in NSA, that has responsibility for encouraging widespread availability of trusted systems throughout the U.S. Federal Government. It has established criteria for, and performed evaluations of, computer and network systems that have a TCB. (See: Rainbow Series, TCSEC.)

$ National Information Assurance Partnership (NIAP)

(N) A joint initiative of NIST and NSA to enhance the quality of commercial products for information security and increase consumer confidence in those products through objective evaluation and testing methods.

Tutorial: NIAP is registered, through the U.S. DoD, as a National Performance Review Reinvention Laboratory. NIAP functions include the following:

Developing tests, test methods, and other tools that developers and testing laboratories may use to improve and evaluate security products.

Collaborating with industry and others on research and testing programs.

Using the Common Criteria to develop protection profiles and associated test sets for security products and systems.

Cooperating with the NIST National Voluntary Laboratory Accreditation Program to develop a program to accredit private- sector laboratories for the testing of information security products using the Common Criteria.

Working to establish a formal, international mutual recognition scheme for a Common Criteria-based evaluation.

$ National Institute of Standards and Technology (NIST)

(N) A U.S. Department of Commerce organization that promotes U.S. economic growth by working with industry to develop and apply technology, measurements, and standards. Has primary U.S. Government responsibility for INFOSEC standards for sensitive unclassified information. (See: ANSI, DES, DSA, DSS, FIPS, NIAP, NSA.)

$ National Reliability and Interoperability Council (NRIC)

(N) An advisory committee chartered by the U.S. Federal Communications Commission (FCC), with participation by network service providers and vendors, to provide recommendations to the FCC for assuring reliability, interoperability, robustness, and security of wireless, wireline, satellite, cable, and public data communication networks.

$ national security

(O) /U.S. Government/ The national defense or foreign relations of the United States of America.

$ National Security Agency (NSA)

(N) A U.S. DoD organization that has primary U.S. Government responsibility for INFOSEC standards for classified information and for sensitive unclassified information handled by national security systems. (See: FORTEZZA, KEA, MISSI, national security system, NIAP, NIST, SKIPJACK.)

$ national security information

(O) /U.S. Government/ Information that has been determined, pursuant to Executive Order 12958 or any predecessor order, to require protection against unauthorized disclosure. [C4009]

$ national security system

(O) /U.S. Government/ Any Government-operated information system for which the function, operation, or use (a) involves intelligence activities; (b) involves cryptologic activities related to national security; (c) involves command and control of military forces; (d) involves equipment that is an integral part of a weapon or weapon system; or (e) is critical to the direct fulfillment of military or intelligence missions and does not include a system that is to be used for routine administrative and business applications (including payroll, finance, logistics, and personnel management applications). [Title 40 U.S.C. Section 1552, Information Technology Management Reform Act of 1996.] (See: type 2 product.)

$ natural disaster

(I) /threat action/ See: secondary definitions under "corruption" and "incapacitation".

$ NCSC

(O) See: National Computer Security Center.

$ need to know, need-to-know

(I) The necessity for access to, knowledge of, or possession of specific information required to carry out official duties.

Usage: The compound "need-to-know" is commonly used as either an adjective or a noun.

Tutorial: The need-to-know criterion is used in security procedures that require a custodian of sensitive information, prior to disclosing the information to someone else, to establish that the intended recipient has proper authorization to access the information.

$ network

(I) An information system comprised of a collection of interconnected nodes. (See: computer network.)

$ Network Hardware Layer

(I) See: Internet Protocol Suite.

$ Network Interface Layer

(I) See: Internet Protocol Suite.

$ Network Layer Security Protocol (NLSP).

(N) An OSI protocol (IS0 11577) for end-to-end encryption services at the top of OSIRM Layer 3. NLSP is derived from SP3 but is more complex. (Compare: IPsec.)

$ Network Substrate Layer

(I) Synonym for "Network Hardware Layer".

$ network weaving

(I) A penetration technique in which an intruder avoids detection and traceback by using multiple, linked, communication networks to access and attack a system. [C4009]

$ NIAP

(N) See: National Information Assurance Partnership.

$ nibble

(D) Half of a byte (i.e., usually, 4 bits).

Deprecated Term: To avoid international misunderstanding, IDOCs SHOULD NOT use this term; instead, state the size of the block explicitly (e.g., "4-bit block"). (See: Deprecated Usage under "Green Book".)

$ NIPRNET

(O) The U.S. DoD's common-use Non-Classified Internet Protocol Router Network; the part of the Internet that is wholly controlled by the U.S. DoD and is used for official DoD business.

$ NIST

(N) See: National Institute of Standards and Technology.

$ NLSP

(N) See: Network Layer Security Protocol

$ no-lone zone

(I) A room or other space or area to which no person may have unaccompanied access and that, when occupied, is required to be occupied by two or more appropriately authorized persons. [C4009] (See: dual control.)

$ no-PIN ORA (NORA)

(O) /MISSI/ An organizational RA that operates in a mode in which the ORA performs no card management functions and, therefore, does not require knowledge of either the SSO PIN or user PIN for an end user's FORTEZZA PC card.

$ node

(I) A collection of related subsystems located on one or more computer platforms at a single site. (See: site.)

$ nonce

(I) A random or non-repeating value that is included in data exchanged by a protocol, usually for the purpose of guaranteeing liveness and thus detecting and protecting against replay attacks. (See: fresh.)

$ non-critical

See: critical.

$ non-repudiation service

1. (I) A security service that provide protection against false denial of involvement in an association (especially a communication association that transfers data). (See: repudiation, time stamp.)

Tutorial: Two separate types of denial are possible -- an entity can deny that it sent a data object, or it can deny that it received a data object -- and, therefore, two separate types of non-repudiation service are possible. (See: non-repudiation with proof of origin, non-repudiation with proof of receipt.)

2. (D) "Assurance [that] the sender of data is provided with proof of delivery and the recipient is provided with proof of the sender's identity, so neither can later deny having processed the data." [C4009]

Deprecated Definition: IDOCs SHOULD NOT use definition 2 because it bundles two security services -- non-repudiation with proof of origin, and non-repudiation with proof of receipt -- that can be provided independently of each other.

Usage: IDOCs SHOULD distinguish between the technical aspects and the legal aspects of a non-repudiation service:

"Technical non-repudiation": Refers to the assurance a relying party has that if a public key is used to validate a digital signature, then that signature had to have been made by the corresponding private signature key. [SP32]

"Legal non-repudiation": Refers to how well possession or control of the private signature key can be established. [SP32]

Tutorial: Non-repudiation service does not prevent an entity from repudiating a communication. Instead, the service provides evidence that can be stored and later presented to a third party to resolve disputes that arise if and when a communication is repudiated by one of the entities involved.

Ford describes the six phases of a complete non-repudiation service and uses "critical action" to refer to the act of communication that is the subject of the service [For94, For97]:
      --------   --------   --------   --------   --------   . --------
      Phase 1:   Phase 2:   Phase 3:   Phase 4:   Phase 5:   . Phase 6:
      Request    Generate   Transfer   Verify     Retain     . Resolve
      Service    Evidence   Evidence   Evidence   Evidence   . Dispute
      --------   --------   --------   --------   --------   . --------

      Service    Critical   Evidence   Evidence   Archive    . Evidence
      Request => Action  => Stored  => Is      => Evidence   . Is
      Is Made    Occurs     For Later  Tested     In Case    . Verified
                 and        Use |          ^      Critical   .    ^
                 Evidence       v          |      Action Is  .    |
                 Is         +-------------------+ Repudiated .    |
                 Generated  |Verifiable Evidence|------> ... . ----+
                            +-------------------+

      Phase / Explanation
      -------------------
      1. Request service: Before the critical action, the service
         requester asks, either implicitly or explicitly, to have
         evidence of the action be generated.
      2. Generate evidence: When the critical action occurs, evidence is
         generated by a process involving the potential repudiator and
         possibly also a trusted third party.
      3. Transfer evidence: The evidence is transferred to the requester
         or stored by a third party, for later use (if needed).
      4. Verify evidence: The entity that holds the evidence tests it to
         be sure that it will suffice if a dispute arises.
      5. Retain evidence: The evidence is retained for possible future
         retrieval and use.
      6. Resolve dispute: In this phase, which occurs only if the
         critical action is repudiated, the evidence is retrieved from
         storage, presented, and verified to resolve the dispute.
$ non-repudiation with proof of origin

(I) A security service that provides the recipient of data with evidence that proves the origin of the data, and thus protects the recipient against an attempt by the originator to falsely deny sending the data. (See: non-repudiation service.)

Tutorial: This service is a strong version of data origin authentication service. This service can not only verify the identity of a system entity that is the original source of received data; it can also provide proof of that identity to a third party.

$ non-repudiation with proof of receipt

(I) A security service that provides the originator of data with evidence that proves the data was received as addressed, and thus protects the originator against an attempt by the recipient to falsely deny receiving the data. (See: non-repudiation service.)

$ non-volatile media

(I) Storage media that, once written into, provide stable storage of information without an external power supply. (Compare: permanent storage, volatile media.)

$ NORA

(O) See: no-PIN ORA.

$ notarization

(I) Registration of data under the authority or in the care of a trusted third party, thus making it possible to provide subsequent assurance of the accuracy of characteristics claimed for the data, such as content, origin, time of existence, and delivery. [I7498-2] (See: digital notary.)

$ NRIC

(N) See: Network Reliability and Interoperability Council.

$ NSA

(N) See: National Security Agency

$ null

(N) /encryption/ "Dummy letter, letter symbol, or code group inserted into an encrypted message to delay or prevent its decryption or to complete encrypted groups for transmission or transmission security purposes." [C4009]

$ NULL encryption algorithm

(I) An algorithm [R2410] that is specified as doing nothing to transform plaintext data; i.e., a no-op. It originated because ESP always specifies the use of an encryption algorithm for confidentiality. The NULL encryption algorithm is a convenient way to represent the option of not applying encryption in ESP (or in any other context where a no-op is needed). (Compare: null.)

M <- 4. Definitions -> O