Access Control : Access Control ensures that resources are only granted to those users who are entitled to them.
Access Control List (ACL) : A mechanism that implements access control for a system resource by listing the identities of the system entities that are permitted to access the resource.
Access Control Service : A security service that provides protection of system resources against unauthorized access. The two basic mechanisms for implementing this service are ACLs and tickets.
Access Management Access : Management is the maintenance of access information which consists of four tasks: account administration, maintenance, monitoring, and revocation.
Access Matrix : An Access Matrix uses rows to represent subjects and columns to represent objects with privileges listed in each cell.
Account Harvesting : Account Harvesting is the process of collecting all the legitimate account names on a system.
ACK Piggybacking : ACK piggybacking is the practice of sending an ACK inside another packet going to the same destination.
Active Content : Program code embedded in the contents of a web page. When the page is accessed by a web browser, the embedded code is automatically downloaded and executed on the user's workstation. Ex. Java, ActiveX (MS)
Activity Monitors : Activity monitors aim to prevent virus infection by monitoring for malicious activity on a system, and blocking that activity when possible.
Address Resolution Protocol (ARP) : Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address to a physical machine address that is recognized in the local network. A table, usually called the ARP cache, is used to maintain a correlation between each MAC address and its corresponding IP address. ARP provides the protocol rules for making this correlation and providing address conversion in both directions.
Advanced Encryption Standard (AES) : An encryption standard being developed by NIST. Intended to specify an unclassified, publicly-disclosed, symmetric encryption algorithm.
Ampere (amp) : The unit of measurement for the rate of electrical current flow characterized by the symbols l (in Ohm’s law formulas) or A. One ampere is the current flowing through one ohm of resistance at one volt potential.
Annunciator : An audible and visual signaling device.
Anti-passback : A means of preventing the sharing of an access control credential. Anti-passback can be based upon disabling a credential for a period of time after it is used, or by remembering the credential-holder’s in/out status.
Audit trail : A means of recording and saving access control event history for later review.
Authorized release device : A device that when activated allows authorized persons to enter or exit monitored and controlled openings without triggerring an alarm. The authorized released may be a keyed switch, a card reader, a digital code reader and so forth.