Password hashing: never store the plaintext

PawWalk needs accounts — and one rule dominates

A walker signs up with an email and a password, then logs back in later. The tempting shortcut is to save that password in the User row exactly as typed. Never do this. The moment your database leaks — a stray backup, a logged query, a bad SELECT — every plaintext password is out, and people reuse passwords across every site they touch.

The rule every backend obeys: you never store the password, you store a one-way hash of it. A hash is a fingerprint you can compute forwards but never run backwards to recover the input. At login you hash what the user typed and compare fingerprints. Even you, running the server, must be unable to read a user's password back.

The senior pitch: Plaintext passwords aren't a bug you fix later — they're a breach you already shipped. The database is assumed hostile; hashing is what makes a leak survivable.