SHA-256 is a hash function in the SHA-2 family. SHA stands for Secure Hash Algorithm and refers to a set of cryptographic hash functions designed by the National Security Agency and published by the National Institute of Standards and Technology as a U.S. Federal Information Processing Standard. The cryptographic hash function, a basic tool of modern cryptography, is a mathematical algorithm that maps data of arbitrary size to a bit array of a fixed size ("hash"). A hash is like a signature or fingerprint for a data set. SHA-256 uses 32-byte words. In computing, a word is the natural unit of data used by a particular processor design. SHA-256 is considered a "one-way" function and thus is suitable for checking the integrity of data.
SHA-256 (produces a 256-bit (32-byte) hash value):