I am using
[MD5] is a mathematical algorithm that maps data of arbitrary size to a bit string of a fixed size (a hash function) which is designed to also be a one-way function, that is, a function which is infeasible to invert.
Leaving aside potential vulnerabilities, there's no way to get the original data that produced the hash. And that's the idea. If some bad guy get access to your database, he won't be able to know your users' passwords.