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Search Search CSRC MENU Search Search Projects Publications Expand or Collapse Drafts for Public Comment All Public Drafts Final Pubs FIPS (standards) Special Publications (SP s ) IR (interagency/internal reports) CSWP (cybersecurity white papers) ITL Bulletins Project Descriptions Journal Articles Conference Papers Books Topics Expand or Collapse Security & Privacy Applications Technologies Sectors Laws & Regulations Activities & Products News & Updates Events Glossary About CSRC Expand or Collapse Computer Security Division Cryptographic Technology Software Security Group Hardware Security Group Security Engineering and Risk Management Applied Cybersecurity Division Cybersecurity and Privacy Applications National Cybersecurity Center of Excellence (NCCoE) National Initiative for Cybersecurity Education (NICE) Contact Us Information Technology Laboratory Computer Security Resource Center Publications NIST SP 800-224 (Initial Public Draft) Keyed-Hash Message Authentication Code (HMAC): Specification of HMAC and Recommendations for Message Authentication Share to Facebook Share to X Share to LinkedIn Share ia Email Documentation Topics Date Published: June 28, 2024 Comments Due: September 6, 2024 (public comment period is CLOSED) Email Questions to: [email protected] Planning Note ( 06/23/2025 ): See the FIPS 198-1 record for information about submitting comments on the proposed withdrawal of that standard. Comments are due by July 23, 2025. Author(s) Meltem Sönmez Turan (NIST) , Luís T. A. N. Brandão (Strativia) Announcement This publication includes the HMAC specification from Federal Information Processing Standard (FIPS) 198-1 , The Keyed-Hash Message Authentication Code (HMAC) (2008) and incorporates some requirements from SP 800-107r1 (Revision 1), Recommendation for Applications Using Approved Hash Algorithms (2012). This development was proposed by the Crypto Publication Review Board based on the reviews of FIPS 198-1 and SP 800-107r1 in 2022. The final version of SP 800-224 is expected to be published concurrently with the withdrawal of FIPS 198-1. The public comment period is open through September 6, 2024. Submit comments to [email protected] ; comments received in response to this request will be posted here after the due date. Abstract A message authentication code (MAC) scheme is a symmetric-key cryptographic mechanism that can be used with a secret key to produce and verify an authentication tag, which enables detecting unauthorized modifications to data (also known as a message). This NIST Special Publication (whose current version is an initial public draft) specifies the keyed-hash message authentication code (HMAC) construction, which is a MAC scheme that uses a cryptographic hash function as a building block. The publication also specifies a set of requirements for using HMAC for message authentication, including a list of NIST-approved cryptographic hash functions, requirements on the secret key, and parameters for optional truncation. A message authentication code (MAC) scheme is a symmetric-key cryptographic mechanism that can be used with a secret key to produce and verify an authentication tag, which enables detecting unauthorized modifications to data (also known as a message). This NIST Special Publication (whose current... See full abstract A message authentication code (MAC) scheme is a symmetric-key cryptographic mechanism that can be used with a secret key to produce and verify an authentication tag, which enables detecting unauthorized modifications to data (also known as a message). This NIST Special Publication (whose current version is an initial public draft) specifies the keyed-hash message authentication code (HMAC) construction, which is a MAC scheme that uses a cryptographic hash function as a building block. The publication also specifies a set of requirements for using HMAC for message authentication, including a list of NIST-approved cryptographic hash functions, requirements on the secret key, and parameters for optional truncation. Hide full abstract Keywords cryptography ; hash function ; HMAC ; MAC ; message authentication code ; PRF ; pseudorandom function ; standard ; truncation Control Families None selected Documentation Publication: https://doi.org/10.6028/NIST.SP.800-224.ipd Download URL Supplemental Material: Comments received on SP 800-224 ipd (pdf) Document History: 06/28/24: SP 800-224 (Draft) Topics Security and Privacy message authentication HEADQUARTERS 100 Bureau Drive Gaithersburg, MD 20899 X (link is external) facebook (link is external) linkedin (link is external) instagram (link is external) youtube (link is external) rss govdelivery (link is external) Want updates about CSRC and our publications? Subscribe Contact Us | Our Other Offices Send inquiries to [email protected] Site Privacy Accessibility Privacy Program Copyrights Vulnerability Disclosure No Fear Act Policy FOIA Environmental Policy Scientific Integrity Information Quality Standards Commerce.gov Science.gov USA.gov Vote.gov