SHA Hash Generator

A cryptographic hash function takes an input of any size and produces a fixed-length output, called a digest, such that the same input always produces the same digest, a tiny change in input produces a completely different digest, and it's computationally infeasible to reconstruct the original input from the digest alone. SHA-1, SHA-256, SHA-384, and SHA-512 are all part of the SHA family, differing mainly in digest length, from 160 to 512 bits, and the number of computational rounds involved.

Hashes like these are used to verify that data hasn't been altered — comparing the hash of a downloaded file against a published value, checking that a string matches a stored hash, or generating a short fingerprint of a larger piece of text or data for comparison purposes. They are not used to store data for later retrieval, since hashing is a one-way operation.

SHA-1 is no longer considered secure against a determined attacker because practical collision attacks have been demonstrated against it, where two different inputs produce the same hash, so it should be avoided for anything security-sensitive like digital signatures, though it's still fine for basic checksums. SHA-256 or SHA-512 are the safer default choice today, and none of the SHA functions here are appropriate for hashing passwords, which need a purpose-built, slow algorithm like bcrypt or Argon2 instead.