Glossary of Key Information Security Terms (NIST) part 16

Controlled Unclassified Information (CUI) –

A categorical designation that refers to unclassified information that does not meet the standards for National Security Classification under Executive Order 12958, as amended, but is (i) pertinent to the national interests of the United States or to the important interests of entities outside the federal government, and (ii) under law or policy requires protection from unauthorized disclosure, special handling safeguards, or prescribed limits on exchange or dissemination. Henceforth, the designation CUI replaces "Sensitive But Unclassified" (SBU).

Controlling Authority –

Official responsible for directing the operation of a cryptonet and for managing the operational use and control of keying material assigned to the cryptonet.

Cookie –

A piece of state information supplied by a Web server to a browser, in a response for a requested resource, for the browser to store temporarily and return to the server on any subsequent visits or requests. Data exchanged between an HTTP server and a browser (a client of the server) to store state information on the client side and retrieve it later for server use.

Cooperative Key Generation –

Electronically exchanging functions of locally generated, random components, from which both terminals of a secure circuit construct traffic encryption key or key encryption key for use on that circuit. See Per-Call Key.

Cooperative Remote Rekeying –

Synonymous with manual remote rekeying.

Correctness Proof –

A mathematical proof of consistency between a specification and its implementation. Counter with Cipher Block Chaining-Message

Authentication Code (CCM) –

A mode of operation for a symmetric key block cipher algorithm. It combines the techniques of the Counter (CTR) mode and the Cipher Block Chaining-Message Authentication Code (CBC-MAC) algorithm to provide assurance of the confidentiality and the authenticity of computer data.

Countermeasure –

Actions, devices, procedures, or techniques that meet or oppose (i.e., counters) a threat, a vulnerability, or an attack by eliminating or preventing it, by minimizing the harm it can cause, or by discovering and reporting it so that corrective action can be taken.

Countermeasures –

Actions, devices, procedures, techniques, or other measures that reduce the vulnerability of an information system. Synonymous with security controls and safeguards.

Cover-Coding –

A technique to reduce the risks of eavesdropping by obscuring the information that is transmitted.

Coverage –

An attribute associated with an assessment method that addresses the scope or breadth of the assessment objects included in the assessment (e.g., types of objects to be assessed and the number of objects to be assessed by type). The values for the coverage attribute, hierarchically from less coverage to more coverage, are basic, focused, and comprehensive.

Covert Channel –

An unauthorized communication path that manipulates a communications medium in an unexpected, unconventional, or unforeseen way in order to transmit information without detection by anyone other than the entities operating the covert channel.

Covert Channel Analysis –

Determination of the extent to which the security policy model and subsequent lower-level program descriptions may allow unauthorized access to information.

Covert Storage Channel –

Covert channel involving the direct or indirect writing to a storage location by one process and the direct or indirect reading of the storage location by another process. Covert storage channels typically involve a finite resource (e.g., sectors on a disk) that is shared by two subjects at different security levels.

Covert Testing –

Testing performed using covert methods and without the knowledge of the organization’s IT staff, but with the full knowledge and permission of upper management.

Covert Timing Channel –

Covert channel in which one process signals information to another process by modulating its own use of system resources (e.g., central processing unit time) in such a way that this manipulation affects the real response time observed by the second process.

Credential –

An object or data structure that authoritatively binds an identity (and optionally, additional attributes) to a token possessed and controlled by a Subscriber.

Credential –

Evidence attesting to one’s right to credit or authority. Evidence or testimonials that support a claim of identity or assertion of an attribute and usually are intended to be used more than once.

Credential Service Provider – (CSP)

A trusted entity that issues or registers Subscriber tokens and issues electronic credentials to Subscribers. The CSP may encompass Registration Authorities (RAs) and Verifiers that it operates. A CSP may be an independent third party, or may issue credentials for its own use.

Critical Infrastructure –

System and assets, whether physical or virtual, so vital to the U.S. that the incapacity or destruction of such systems and assets would have a debilitating impact on security, national economic security, national public health or safety, or any combination of those matters. [Critical Infrastructures Protection Act of 2001, 42 U.S.C. 5195c(e)]