Salt is not per user, nor is it a cryptographic secret. Salt is only used to make rainbow tables not scale across multiple databases, so each database needs its

Salt is not per user, nor is it a cryptographic secret. Salt is only used to make rainbow tables not scale across multiple databases, so each database needs its own rainbow table calculation. "Pepper" is per user, but widely regarded as unhelpful because, again, it's not cryptographically secure if the database is hacked.