Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The Keyed-Hash Message Authentication Code (HMAC)

Published

Author(s)

National Institute of Standards and Technology (NIST), Elaine Barker, Quynh Dang

Abstract

[Superseded by FIPS 198-1(July 2008): http://www.nist.gov/manuscript-publication-search.cfm?pub_id=901614] This standard describes a keyed-hash message authentication code (HMAC), a mechanism for message authentication using cryptographic hash functions. HMAC can be used with any iterative Approved cryptographic hash function, in combination with a shared secret key. The cryptographic strength of HMAC depends on the properties of the underlying hash function. The HMAC specification in this standard is a generalization of Internet RFC 2104, HMAC, Keyed-Hashing for Message Authentication, and ANSI X9.71, Keyed Hash Message Authentication Code.
Citation
Federal Inf. Process. Stds. (NIST FIPS) - 198
Report Number
198

Keywords

computer security, cryptography, HMAC, MAC, message authentication, Federal Information Processing Standard (FIPS)

Citation

(NIST), N. , Barker, E. and Dang, Q. (2002), The Keyed-Hash Message Authentication Code (HMAC), Federal Inf. Process. Stds. (NIST FIPS), National Institute of Standards and Technology, Gaithersburg, MD (Accessed October 10, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created March 6, 2002, Updated July 25, 2024