Hash Function

Definition

A cryptographic hash function transforms input data into a fixed-length output called a hash or digest. The same input produces the same digest, while a small change normally produces a very different result. Security properties include making it impractical to recover a suitable input from its digest or find distinct inputs with the same digest under the function's intended assumptions. A hash is not encrypted text and is not designed to be decrypted with a secret key. Cryptocurrency systems use hashes for data commitments, identifiers, Merkle trees, and proof-of-work calculations. These uses do not make a hash a guarantee that the original data is truthful; it can commit just as effectively to inaccurate information. Its role is to help detect changes or prove relationships between data. Different hash algorithms have different designs, output lengths, and security characteristics, so their names are not interchangeable.