Cryptographic Hash Function

A hash function is an algorithm that turns a string (for example, a typed sentence) into a unique, fixed length string of characters that the computer understands as the same thing. So the output just looks like a jumble of letters and numbers to the human eye, but in that form a computer can then process and work with the information more efficiently. The fixed length string is sometimes called a message digest or digital fingerprint.

A cryptographic hash function is a secure hash function, used in applications for things like authentication and message integrity.