salt
Definition
In cryptography, a salt is random data that is used as an additional input to a one-way function that hashes data, a password or passphrase.
Usage
Salts are used to safeguard passwords in storage. Historically, only a cryptographic hash function of the password was stored on a system, but over time, additional safeguards were developed to protect against duplicate or common passwords being identifiable (as their hashes are identical).[2] Salting is one such protection.