SHA-3 is a family of cryptographic hash functions, intended to replace sha1 and sha-2. SHA-3 was chosen by NIST in a competition started in November 2007. The winner was declared to be the Keccak family in October 2012. The other finalists in the competition were BLAKE, Grøstl, JH and Skein skein.
Use this tag for questions about the SHA-3 competition itself and how the competing algorithms compare. For questions about a specific algorithm, use the corresponding tag, e.g. keccak for the winner.
As of October 2012, SHA-3 has not yet been formally codified. It is intended that the next version of FIPS PUB 180 will specify Keccak functions with digest sizes 224, 256, 384, 512.