Hashing is the process of generating a small unique digest from a larger string of text. The resulting digest, called the hash value, is a digital representation of the original text, which, once signed (or encrypted) with the private key of the user, is then a digital signature. Digital signatures are based on asymmetric encryption and created to ensure data authentication between parties.

Hashing involves a hash function, or algorithm, through which a data packet is passed to produce a unique hash value of the data message. Any change to the message results in a different hash value when the same algorithm is used. With one-way hash functions using algorithms like MD5 or SHA, it is computationally infeasible that the original message could be revealed from knowledge of the hash value.