NIST Specs 800-63-3
NIST Special Publication 800-63-3 - Digital Identity Guidelines
Offline Documents:
Links to the documents:
Main website: https://pages.nist.gov/800-63-3/
SP 800-63-3 https://pages.nist.gov/800-63-3/sp800-63-3.html
SP 800-63-A https://pages.nist.gov/800-63-3/sp800-63a.html
SP 800-63-B https://pages.nist.gov/800-63-3/sp800-63b.html
SP 800-63-C https://pages.nist.gov/800-63-3/sp800-63c.html