Credit Card would give you the user's name.... but John Smith isn't John Smith, he just happens to have the same name. John Smith #2 could also add John Smith

Credit Card would give you the user's name.... but John Smith isn't John Smith, he just happens to have the same name. John Smith #2 could also add John Smith #1 address to his authorized credit card addresses, but that's a malicious edge case. Old school way of opening a back account online was, you verified yourself online with something YOU KNEW (account number and last debit/credit on the account). Then we'd snail mail you a letter to your known address (something WE KNEW), have you sign it and send it back. -- You could skip the mail it back by having them input a code you mail them. Also things get messy if you have a "jr" in the house. John Smith and John Smith Jr. may both use John Smith and live in the same house. How sensitive is the data and how regulated is your industry would determine the lengths you have to go to.