Authenticate

To confirm the identity of an entity when that identity is presented.

1. To establish, usually by challenge and response, that a transmission attempt is authorized and valid. 2. [To] verify the identity of a user, user device, or other entity, or the integrity of data stored, transmitted, or otherwise exposed to unauthorized modification in an information system (IS), or establish the validity of a transmission. [INFOSEC-99] 3. A challenge given by voice or electrical means to attest to the authenticity of a message or transmission. [JP1] 4. To establish the validity of a claimed identity [POSIX.6]. 5. To establish the validity of a claimed identity [TCSEC].