"Mostly it's the name of their kids..."

Well thats just... sad :-(

 

"If you would use two-way encryption (so be able to decrypt it) you would waste a ton of resources on that."

Okay here's something I didn't know. Explains why company's don't encrypt credit card information

In some countries it's even illegal to store credit card information and that should be avoided unless absolutely impossible! 

If you stored it and it leaks, you can be made responsible if it wasn't secure enough.

 

My code above contains a bug by the way, one I fixed but left in this snippet of code. Can't be too secure.

The issue is in the creation of the random hash...

By the way, if you would store credit card info, these are the rules: https://www.pcisecuritystandards.org/sec.../index.php

 

Credit card information is stored, with AES256/512. That is reverseable, but not really useable on normal sites.