The SHA-2 (Secure Hash Algorithm 2) hash family is a group of cryptographic hash functions designed to provide secure and reliable data integrity verification. Developed by the National Security Agency (NSA) and published by the National Institute of Standards and Technology (NIST) in 2001, SHA-2 includes several variants, such as SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256, each producing hash digests of different lengths.

These hash functions are widely used in various cryptographic applications due to their robust security properties and resistance against collision, pre-image, and second pre-image attacks. The larger variants, like SHA-512, offer increased security and are often preferred in applications where stronger protection is required. The SHA-2 family has become a standard choice for data integrity checks, digital signatures, and other security-sensitive protocols.

Details about the specification can be found in FIPS 180-2 avaliable at https://csrc.nist.gov/files/pubs/fips/180-2/final/docs/fips180-2.pdf.