Technical Summary
The United States of America has adopted a suite of secure hash
algorithms (SHAs), including four beyond SHA-1, as part of a Federal
Information Processing Standard (FIPS), specifically SHA-224, SHA-256,
SHA-384, and SHA-512. This document makes open source code performing
the SHA hash functions conveniently available to the Internet
community. The sample code supports input strings of arbitrary bit
length. Much of the text herein was adapted by the authors from FIPS
180-2.
This document replaces RFC 4634, fixing errata and adding code for an
HMAC-based extract-and-expand key derivation function, HKDF (RFC
5869). As with RFC 4634, code to perform SHA based HMACs is also
included.
Working Group Summary
This document is not the product of any IETF WG.
Document Quality
The document was reviewed by Russ Housley for the IESG.