authentication

Authentication ensures that digital data transmissions are delivered to the intended receiver. Authentication also assures the receiver of the integrity of the message and its source (where or whom it came from). The simplest form of authentication requires a username and password to gain access to a particular account. But authentication protocols can also be based on secret-key encryption, such as DES, or on public-key systems using digital signatures.

See also: DES, PAP, CHAP