A "salt", unlike most uses of a nonce, doesn't derive its benefits from secrecy. The only* benefit of the "salt" is essentially to prevent birthday attacks on

A "salt", unlike most uses of a nonce, doesn't derive its benefits from secrecy. The only* benefit of the "salt" is essentially to prevent birthday attacks on your password database, since any attacker with the passwords probably also has the salts. *-Not strictly true. If a user is rotating through a sequence of passwords, changing the salt will obscure that.