Card Validation Value/Code

The Card Validation Value, Card Validation Code or Card Identification Number
(CVV for Visa / CVC for MasterCard and CIN for American Express)
is a security code printed on the credit card. On Visa and MasterCard,
the three-digit code is on the back signature panel.
The American Express code is four digits and is on the front of the card.

The CVV/CVC/CIN helps validate your purchase as legitimate.