CVV is the 3 or 4 digit security number printed on the back of your card (front of card if American Express).
* MasterCard, Visa, Diners Club, Discover, and JCB credit and debit cards have a three-digit card security code.
The code is not embossed like the card number, and is always the final group of numbers printed on the back signature panel of
the card. New North American MasterCard and Visa cards feature the code in a separate panel to the right of the signature
strip. This has been done to prevent overwriting of the numbers by signing the card. The codes have different names:
"CVC2" (card validation code) MasterCard,
"CVV2" (card verification value) Visa,
"CID" (card identification number) Discover.
* American Express cards have a four-digit code printed on the front side of the card above the number. It is printed flat,
not embossed like the card number. This code is called: "CID" or "unique card code"