Editing SHA-1 (section)

===Cryptography===
{{Further|Cryptographic hash function#Applications}}
SHA-1 forms part of several widely used security applications and protocols, including [[Transport Layer Security|TLS]] and [[Secure Sockets Layer|SSL]], [[Pretty Good Privacy|PGP]], [[Secure Shell|SSH]], [[S/MIME]], and [[IPsec]]. Those applications can also use [[MD5]]; both MD5 and SHA-1 are descended from [[MD4]].

SHA-1 and SHA-2 are the hash algorithms required by law for use in certain [[U.S. government]] applications, including use within other cryptographic algorithms and protocols, for the protection of sensitive unclassified information. FIPS PUB 180-1 also encouraged adoption and use of SHA-1 by private and commercial organizations. SHA-1 is being retired from most government uses; the U.S. National Institute of Standards and Technology said, "Federal agencies should stop using SHA-1 for...applications that require collision resistance as soon as practical, and must use the [[SHA-2]] family of hash functions for these applications after 2010",<ref name="Computer Security Division">{{Cite web |last=Computer Security Division |first=Information Technology Laboratory |date=2017-01-04 |title=NIST Policy on Hash Functions – Hash Functions |url=https://csrc.nist.gov/Projects/Hash-Functions/NIST-Policy-on-Hash-Functions |access-date=2023-08-27 |website=CSRC, NIST |language=EN-US}}</ref> though that was later relaxed to allow SHA-1 to be used for verifying old digital signatures and time stamps.<ref name="Computer Security Division"/>

A prime motivation for the publication of the [[Secure Hash Algorithm]] was the [[Digital Signature Algorithm|Digital Signature Standard]], in which it is incorporated.

The SHA hash functions have been used for the basis of the [[SHACAL]] [[block cipher]]s.