While on the topic, this isn't how passwords work in systems.

Passwords are stored as one way hashes. So it's cryptoed only in one direction, it's lossy, and can't be recovered back to the original password.

When you log on, your cleartext PW is hashed in ephemeral memory/storage and then the cleartext password is thrown away.

That hash is compared to the hash in the DB. If the hash matches, then you have access. If it doesn't, then your PW is incorrect.

Oh my sweet Summer Child. This is definitely how it's supposed to work, but there are plenty of services that just don't know what the fuck they're doing.

Have you ever been on a site that has a stupid-low character limit for a password? There's literally no reason to do that, all the hashes are going to end up the same size in the DB anyway regardless of the original string length. Even bcrypt's max secret character limit is 70-something characters.

Ever change a password and have it not work on the next login because they're silently truncating it after a certain character limit? Ever get an email with an actual password in it?

The only reason you would do things like this is if you're storing/processing passwords in plaintext and not hashing it client-side first.

I can think of 3 offenders of this off the top of my head. It's a lot more common than you'd think.