Operation of a communication network in which transmission may occur between the control station and any tributary station, but not between tributary stations.

An organization provided by some communications service providers to coordinate services between the companies and vendors.

A service offered by Bell Operating Companies that provides functions and features comparable to those provided by a PBX or a PABX.
Note: "Centrex® C. O. "indicates that all equipment except the attendant's position and station equipment is located in the central office. "Centrex® C. U. "indicates that all equipment, including the dial switching equipment, is located on the customer's… (Read More →)

1. In cryptography, the public key and the identity of an entity, with other information, rendered unforgeable by digitally signing the entire information with the private key of the issuing certification authority. [After X9.42] Synonym digital certificate.
2. [A] record holding security information about an information-system (IS) user and vouches to the truth and accuracy of the information it contains.… (Read More →)

In cryptography, an order suspending the use of a certificate.
Note: A certificate hold is a security procedure that is analogous to placing a hold on a bank account to prevent the fraudulent use of the account (including the transfer of funds from that account).

In cryptography, the information in a certificate which is signed. [After X9.57]

[The] process whereby certificates . . . are generated, stored, protected, transferred, loaded, used, and destroyed. [INFOSEC-99]

See CRL.

In cryptography, an integer value that is (a) unique within the issuing certificate authority (CA), and (b) unambiguously associated with a certificate issued by that CA. [After X.509]

In cryptography, a station, agency, or individual user that needs to know, with certitude, the public key of another entity. [After X.509]