If you must keep credit card numbers on file, that process needs to be accompanied by security provisions that go beyond encryption or using access control. Employees need to be trained to recognize social engineering scams like the ones in this chapter. That fellow employee you've never met in person but who has become a telephone friend may not be who he or she claims to be. He may not have the "need to know" to access sensitive customer information, because he may not actually work for the company at all.