SHA-2

File Format
Name	SHA-2
Ontology	Electronic File Formats Encryption SHA-2
PRONOM	fmt/991
Released	2002

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 (openssl dgst [-sha224|-sha256|-sha384|-sha512])
• GNU coreutils → sha224sum, sha256sum, sha384sum, sha512sum

See also

• SHA-1 (predecessor)
• SHA-3 (successor)

Links

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