Encryption is good. Even better, for credit cards, use reference numbers from the CC company instead that identify an individual account (to the CC company) but

Encryption is good. Even better, for credit cards, use reference numbers from the CC company instead that identify an individual account (to the CC company) but aren't the number can't be used for obtaining credit, just discussing the account. Encryption fine, but better not to store volatiles at all if you don't have to.