Card Verification Value 2 (CVV2)

Card Verification Value 2 (CVV2) is the three-digit number that is printed on the signature panel on the back of a Visa payment card, after the full account number or the last four digits of the account number. The number is generated when the card is issued, by hashing the card number and expiration date under a key known only to the card issuer. The CVV2 is used in card-not-present transactions to ensure that the card is valid. Card-not-present merchants ask the customer for the CVV2 and submit it as part of their authorization request. Merchants are prohibited from storing CVV2 information.