The Card Security Code (CSC) or Card Verification Value (CVV) is an additional level of security recently introduced by American Express, Mastercard and Visa. It essentially proves that you are physically holding the card at the time of the transaction because the only place where the security code can be found is on the card itself.

For American Express, in some cases the Security Code may be located on the front of your Card in either the center, the lower left-hand corner, or on the back of your Card.