Storing partial credit card numbers

Question

Possible Duplicates:

1. Best practices for taking and storing credit card information with PHP
2. Storing credit card details
3. Storing Credit Card Infor

Answer 1

The accepted pattern is don't store them at all.

In certain jurisdictions you may be breaking the law by storing them or any part of them.

You could instead, store a one-way (and therefore unrecoverable) hash of the credit card number.