3DES (Triple DES): An enhancement to the original DES algorithm that uses multiple keys to encrypt plaintext. See also Data Encryption Standard (DES).
AAA: Shorthand for the system controls authentication, authorization, and accountability.
abstraction: A process that involves viewing an application from its highest-level functions, which makes lower-level functions abstract.
access control: The capability to permit or deny the use of an object (a passive entity, such as a system or file) by a subject (an active entity, such as a person or process).
access control list (ACL): Lists the specific rights and permissions assigned to a subject for a given object.
Access Matrix Model: Provides object access rights (read/write/execute or R/W/X) to subjects in a DAC system. An access matrix consists of ACLs and capability lists. See also access control list (ACL) and discretionary access control (DAC).
accreditation: An official, written approval for the operation of a specific system in a specific environment, as documented in a certification report.
active-active: A clustered configuration in which all of the nodes in a system or network are load balanced, synchronized, and active. If one node fails, the other node(s) continue providing services seamlessly.
active-passive: A clustered configuration in which only one node in a system or network is active. If the primary node fails, a passive node becomes active and continues providing services, usually after a short ...