NIST to Update Special Publication 800-56A and Revise 800-56C

After receiving public comments in response to its July 2025 proposal, NIST has decided to maintain the Special Publication (SP) 800-56 reports as follows:

• Update NIST SP 800-56Ar3, Recommendation for Pair-Wise Key-Establishment Schemes Using Discrete Logarithm Cryptography (2018)
• Reaffirm NIST SP 800-56Br2, Recommendation for Pair-Wise Key-Establishment Using Integer Factorization Cryptography (2019)
• Revise NIST SP 800-56Cr2, Recommendation for Key-Derivation Methods in Key-Establishment Schemes (2020) 

See an explanation of these decision options.

The main goals of updating SP 800-56Ar3 are to:

• Approve xx-coordinate-only implementations of certain Elliptic Curve Cryptography (ECC) key-agreement schemes that are widely adopted and essentially equivalent to the existing specifications
• Align with the curve requirements that are already specified in SP 800-186
• Improve the editorial quality

Presently, NIST will not change SP 800-56Br2. After SP 800-56Ar3 is updated and SP 800-56Cr2 is revised, SP 800-56Br2 will be updated to cite the current editions of all references.

The main goals of revising SP 800-56Cr2 are to:

• Allow the shared secret ZZ to incorporate a shared secret obtained from an approved key-encapsulation mechanism (KEM)
• Allow greater flexibility in the formatting of hybrid shared secrets
• Approve KMAC (Keccak Message Authentication Code) as an option in the two-step key derivation method, for the randomness extraction step (in addition to the expansion step)

More details of this review are available at NIST’s Crypto Publication Review Project site. Monitor progress on CSRC News and CSRC Publications, and by subscribing to email updates.