Password hashing and encryption answer different recovery requirements

Password verification usually needs to answer “does this candidate match?” rather than recover the original password. A password-hashing function, with a unique salt and an appropriate work factor, supports that requirement while increasing the cost of offline guessing after a database leak.

Encryption has a different contract: whoever has the appropriate decryption key can recover the plaintext. Encrypting every stored login password creates a recovery capability that ordinary password verification does not need. A fast general-purpose digest alone also misses the intended resistance to large numbers of password guesses.

Illustrative contrast: a login service can verify an entered password against an adaptive password hash. A delivery service needs to recover a shipping address to print a label, so an irreversible hash is not a replacement for controlled access and, where appropriate, encryption of that address.

Choose maintained password-storage libraries, benchmark work factors for the actual service, and plan upgrades. Do not interpret “one-way” as “unguessable”: weak passwords can still be guessed and checked against stolen hashes. This post supplies a design distinction, not current deployment-specific parameter sizing.