SHA-2

SHA-2 is a family of cryptographic hash functions.

Details
As of 2012, SHA-2 has six defined-and-approved members, which can be classified into two sub-families.


 * SHA-2 family
 * SHA-256 sub-family
 * SHA-224 (224-bit)
 * SHA-256 (256-bit)
 * SHA-512 sub-family
 * SHA-512/224 (224-bit)
 * SHA-512/256 (256-bit)
 * SHA-384 (384-bit)
 * SHA-512 (512-bit)

The specification also defines t-bit hashes named SHA-512/t, for a wide range of values of t, but it only approves the aforementioned SHA-512/224 and SHA-512/256 for use.

Specifications

 * FIPS PUB 180-2 (1 Aug. 2002): SHA-256, SHA-384, SHA-512
 * FIPS PUB 180-3 (Oct. 2008): Adds SHA-224
 * FIPS PUB 180-4 (Mar. 2012): Adds SHA-512/224, SHA-512/256

Software

 * OpenSSL
 * GNU coreutils → sha224sum, sha256sum, sha384sum, sha512sum

Links

 * Wikipedia article
 * SHA-512/256 - 2010 report by Gueron, Johnson, Walker
 * Towards the Perfect Coin Flip: The NIST Randomness Beacon (uses SHA512)