The Message Authentication Code reference article from the English Wikipedia on 24-Jul-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Message Authentication Code

In cryptography, a message authentication code (MAC) algorithm (also keyed-hash function) is an algorithm for generating a short string of information used to authenticate a message. A MAC algorithm involves a one-way hash function or block cipher and accepts a secret key as well as a message as input and produces a MAC (sometimes known as tag). The purpose of the code is to ensure the authenticity as well as the integrity of a message in transit.

Popular MAC algorithms include HMAC, OMAC and PMAC.

External links

• RSA FAQ's entry on MACs

---

The Message Authentication Code (MAC) is an ANSI standard for a short string of information used to authenticate a message which is based on DES, and is also known as the Data Authentication Code. There are alternatives; not using DES is one, encrypting a message digest is another, as is using a stream cipher, etc.

Message digests (or the output from cryptographic hash functions) were formerly widely used for the purpose of providing a message integrity check, but the message authentication code construction resolved some security problems and so is now preferred.

This is the "Message Authentication Code" reference article from the English Wikipedia. All text is available under the terms of the GNU Free Documentation License. See also our Disclaimer.