Encrypting/Decrypting Passwords to and from a MySQ

Question

I'm starting to create a user system for my website, and what I want to do is to have the passwords encrypted, rather than plaintext. I'm using PHP/MySQL, so I figured crypt() is a good place to start. However, I'm brand new to cryptography like this, and I'm having trouble understanding exactly how it works. Does anybody know how to implement, at the simplest level, a way for passwords to be stored as an encrypted string, but always be able to be decrypted, without a security issue?

Answer 1

PHP has some built-in has functions, such as md5(). When I was learning I found IBM's primer very useful - I'd highly recommend looking at that.

As an aside, I would advise against being able to decrypt a password. The only person who should know their password is a user! This is why we store hashed versions of passwords which we can check against, rather than storing encrypted passwords which can be decrypted..