What is SHA256?
SHA-256 (Secure Hash Algorithm 256) is a cryptographic hash function that takes an input (or 'message') and returns a
fixed-size string of characters, which is a 'digest' that is unique to the original input. The same input will always
produce the same output, but even a small change to the input will produce a very different output. This makes it useful
for checking the integrity of data, as any change to the input will result in a different digest, which can be detected.
It is widely used in cryptocurrency and blockchain technology.
SHA-2 includes significant changes from its predecessor, SHA-1. 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-256 and SHA-512 are novel hash functions computed with 32-bit and 64-bit words, respectively. They use different shift amounts and additive constants, but their structures are otherwise virtually identical, differing only in the number of rounds. SHA-224 and SHA-384 are truncated versions of SHA-256 and SHA-512 respectively, computed with different initial values. SHA-512/224 and SHA-512/256 are also truncated versions of SHA-512, but the initial values are generated using the method described in Federal Information Processing Standards (FIPS) PUB 180-4.