See MAC in Computer
(2) (Message Authentication Code) A number computed from the contents of a text message that is used to prove the integrity of a message. The MAC is a checksum that is computed using an algorithm based on the DES or AES ciphers, which use a secret key. The MAC is then sent with the message. The recipient recomputes the MAC at the other end using the same algorithm and secret key and compares it to the one that is sent. If they are the same, it is assumed that the message has not been tampered with.
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