Message Authentication Code (MAC)
Security
A cryptographic checksum on data that uses a symmetric key to detect both accidental and intentional modifications of the data.
Telecommunications
A bit string that is a function of both data (either plaintext or ciphertext) and a secret key, and that is attached to the data in order to allow data authentication. Note: The function used to generate the message authentication code must be a one-way function. [2382-pt.8] 2. Data associated with an authenticated message allowing a receiver to verify the integrity of the message. [INFOSEC-99]