Secure Hash Algorithm 2 (SHA-2) is a set of cryptographic hash functions designed by the NSA. The SHA-2 family consists of six hash functions with digests (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-2 includes significant changes from its predecessor, SHA-1.