SHA256   SHA224  

SHA-1. SHA-2 family consists of six hash functions with digest (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256.

SHA-256 and SHA-512 are new hash functions computed with 32-bit and 64-bit words respectively. They use different numbers of shift and additive constants, but their structures are otherwise almost identical, differing only in the number of rounds. SHA-224 and SHA-384 are simply truncated versions of the first two, computed with different initial value. SHA-512/224 and SHA-512/256 are also truncated versions of SHA-512, but initial values are generated using the method described in the Federal the information processing standards (FIPS) PUB 180-4. SHA-2 was published in 2001 by the national Institute of standards and technology (NIST) U.S. Federal standard (FIPS). The SHA-2 family of algorithms is patented in us patent 6829355. The United States issued a patent under a free license.

Currently the best public attacks break the prototype resistance by 52 out of 64 rounds of SHA-256 or 57 out of 80 rounds of Sha-512 algorithm, and collision resistance by 46 out of 64 rounds of Sha-256 algorithm.