SHA-1 is a hash function that is two generations old, no longer considered secure for all uses and should only be used for backward compatibility.
SHA-1 is a cryptographic hash function that is no longer considered collision-resistant and should only be used for backward compatibility.
- In 2006, NIST issued a policy stating that:
"Federal agencies should stop using SHA-1 ... as soon as practical, and must use the SHA-2 family of hash functions for these applications after 2010."
In 2020, Leurent et. al. showed that certificate signatures could be forged using collisions found in the SHA-1 algorithm