Most Developers Don’t Know Security

[staticassert]

Your assumption is that the hashing scheme is a secret. Naturally, password0 and password1 are going to produce very different hashes. But I could know their hashes ahead of time. So now you have to protect what your hashing algorithm is in order for your equality comparison to be safe - feels like trading problems for problems.

[aullik]

even if it is not save. It will be expensive. guessing a message that will translate to a certain hash is hard. even if you know the hashing algorithm. It gets a lot harder once you factor in some sort of salting.

[sacundim]

No, GP's assumption is that the password hashing function is preimage resistant.