CVV is an additional service which is intended to assist the combating of fraud in Card Not Present transactions (i.e. online, mail or phone purchases).
The purpose of the Card Verification Value is to ensure that the data stored on the magnetic stripe of the card is valid and was generated by the issuing bank. The CVV code is the final 3 digits of the number shown on the signature strip of the card.
Address Verification Services ensure that the supplied address details match those registered for the card.