Currently i wrote an e-mail verification code that sends a link that has user's GUID as his verification code. I don't think that this is safe, so i want to hear from you, what are the best and easiest methods of creating a verification code?
The easiest-easiest way i think is to create some kind of hash and put it in the database, and when user clicks on his link, it compares link value with hash in my database. But why would i need a single column in my database that is used only once? That's a waste of space.