NIST Password Guidelines
Since 2014, the National Institute of Standards and Technology (NIST), a U.S. federal agency, has issued guidelines for managing digital identities via Special Publication 800-63B. The latest revision (rev. 3) was released in 2017, and has been updated as recently as 2019. Revision 4 was made available for comment and review; however, revision 3 is still the standard as of the time of this blog post.