What is a Card Verification Code?
A special number with a very special purpose.

A card verification code (also called CVC, CSC, or CVV) is a special number printed on your credit card that indicates your possession of the card at the time of the purchase. For your protection, neither this number or any part of your credit card data is stored on our server.

You'll find the 3-digit code used for Visa, MasterCard and Visa on the back of the card, and the 4-digit code used for American Express on the front of the card.