NIST SP 800-63
Also known as: NIST 800-63 · NIST Digital Identity Guidelines
Definition
NIST SP 800-63 is the US federal standard for digital identity — three sub-publications covering identity proofing (800-63A), authentication (800-63B), and federation (800-63C).
The 800-63 family is the reference for identity assurance in the US federal government and is widely adopted by private-sector identity programs. 800-63A specifies identity-proofing requirements at IAL1/IAL2/IAL3. 800-63B specifies authentication at AAL1/AAL2/AAL3. 800-63C specifies federation assurance at FAL1/FAL2/FAL3.
The Rev. 4 update (in draft / partial publication through 2024-2026) introduces additional safeguards including syncable passkeys, refined fraud requirements, and accessibility expansions.