How does AVS work and where can I find the CV2 number?

The Address Verification Service checks the shopper's address and postcode, as entered at the point of order. The numeric data (billing house/flat number and numerics in the postcode) of the shopper's billing address and postcode is checked against the details of the card issuer. A successful AVS result shows that the person ordering knows the shopper's registered address. This is a good indication that they are the true cardholder and by only delivering to the billing address you will further deter potential fraudsters.

The CV2 value (also known as: CVV/security number) is the last 3 digits of the number on the signature strip on the back of all debit and credit cards including JCB, Diners club and Laser cards. Amex cards differ and have a 4 digit number on the front of the card. In order to enter the correct number, the person placing the transaction must either be in possession of the card, or must have made a note of the CV2 number whilst handling the card.

You can see from these images how the CV2 number would appear on a credit/debit card and Amex.