One-key MAC

"CMAC" redirects here. For other uses, see CMAC (disambiguation).

One-key MAC (OMAC) is a family of message authentication codes constructed from a block cipher much like the CBC-MAC algorithm. It may be used to provide assurance of the authenticity and, hence, the integrity of data. Two versions are defined:

  • The original OMAC of February 2003, which is seldom used.[1] The preferred name is now "OMAC2".[2]
  • The OMAC1 refinement,[2] which became an NIST recommendation in May 2005 under the name CMAC.[3]

OMAC is free for all uses: it is not covered by any patents.[4]

  1. ^ Cite error: The named reference omac03 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference omac1 was invoked but never defined (see the help page).
  3. ^ Dworkin, Morris (2016). "Recommendation for Block Cipher Modes of Operation: The CMAC Mode for Authentication" (PDF). doi:10.6028/nist.sp.800-38b. {{cite journal}}: Cite journal requires |journal= (help)
  4. ^ Rogaway, Phillip. "CMAC: Non-licensing". Retrieved May 27, 2020. Phillip Rogaway's statement on intellectual property status of CMAC