In cryptography, a salt consists of random bits, creating one of the inputs to a one-way function. The other input is usually a password or passphrase. The output of the one-way function can be stored rather than the password, and still be used for authenticating users. The one-way function typically uses a cryptographic hash function. A salt can also be combined with a password by a key derivation function such as PBKDF2 to generate a key for use with a cipher or other cryptographic algorithm.