It turns out that most of the security of credit cards takes place after the actual transaction. It's largely done by using software to look for transactions t

It turns out that most of the security of credit cards takes place after the actual transaction. It's largely done by using software to look for transactions that look somehow wrong, or by reversing charges when you look at your bill at the end of the month and see an obviously incorrect charge. The point is that the system has effectively figured out that they can't make a system that is both sufficiently secure and sufficiently convenient in just a card, so it instead accepts that numbers will be stolen and tries to minimize the damage.