How to use MySQL if making an MMO?

Hello, I'm currently developing a small MMO game that I hope to one day put publicly on the internet. I've spent countless hours trying to figure out how to 1. Have a login system that allows people to register (The passwords some how need to be encrypted so that they can't be stolen or seen by people.) and 2. Somehow store variables on a MySQL server (Like gold etc...) this also needs to be secure so that people can't cheat. If you could point me in the right direction, that would be greatly appreciated as every tutorial/thread I've looked at just doesn't seem right and too insecure.