Draft Special Publication: 800-63B Digital Authentication Guideline

This is great! I was actually looking recently to see if there was any definitive guide to best practices in single and multifactor authentication, and this is a pretty good description. Would be nice if there were a separate guide on actual implementation of such systems.

I really appreciate this section, as I have been frustrated in the past by stupid password complexity requirements that actually reduce the amount of available entropy for passwords: https://pages.nist.gov/800-63-3/sp800-63b.html#appA

Note that this might have been a better link, giving an overview of the whole series and development process: https://pages.nist.gov/800-63-3/