Is inputting a "Create Account" system into a game possible?

So recently, many games have been dying because of lost data, players hacking their levels, etc. so as I was creating my game, those thoughts began to enter my head. So when you join my game, it would ask you to register. The registration is would be simple: 1- Creating a username: The username would consist of 4 numbers, and 6 letters, but it cant be your real username. 2- Password would be anything the player wants it to be, but it must have a minimum of 5 characters.

Then the Username and Password would be saved somewhere, and so will its data, so that whenever an update occurs, the players' data would have already been saved, so that if they DID lose their level, they'd just come to the creator, give him/her their username and password, and BOOM! Everyone's happy.

So would something like that be possible? If yes, what would you have to do?

Ps: I'm not asking for a script. I'm only asking for opinions, and maybe a bit of info on how to make it....