Editing Error detection and correction (section)

=== Cryptographic hash function ===
{{Main|Cryptographic hash function}}
The output of a ''cryptographic hash function'', also known as a ''message digest'', can provide strong assurances about [[data integrity]], whether changes of the data are accidental (e.g., due to transmission errors) or maliciously introduced. Any modification to the data will likely be detected through a mismatching hash value. Furthermore, given some hash value, it is typically infeasible to find some input data (other than the one given) that will yield the same hash value. If an attacker can change not only the message but also the hash value, then a ''keyed hash'' or [[message authentication code]] (MAC) can be used for additional security. Without knowing the key, it is not possible for the attacker to easily or conveniently calculate the correct keyed hash value for a modified message.