The Card Validation Code (CVC) is a three-digit security code that is printed on the back of cards. The number appears in reverse italic at the top of the signature panel at the end (see sample). This program helps validate that a genuine card is being used during a transaction.
All MasterCard cards, both credit and debit, were required to contain CVC by January 1, 1997; all Visa cards must contain CVC by January 1, 2001.