A method for ensuring that data have not been altered. A hash total is the numerical sum of one or more fields in a file, including data not normally used in calculations, such as account number. The original hash total is stored, and when required, the data are recalculated and compared with the original. If data are lost or changed, a mismatch signals an error. Used for decades, hash totals were always a simple verification method.
Hash Totals Are Simple
But cryptographic hashes are not. Used for digital signatures, authentication methods and blockchains, these hash algorithms are more complicated. See hash
and cryptographic hash function