What is a security code?
The security code (also known as a card verification value or "CVV2 code") is an important feature that now appears on the back of most VISA and MasterCard cards, and on the front of American Express cards.
The card security code is a unique three or four-digit number printed on your debit/credit card. The number is not embossed on the card so that it cannot be printed on receipts - making it difficult for anyone other than the genuine cardholder to know it.
Visa, Mastercard, and Discover Credit Cards, use the last three-digit number printed on the reverse of the card.
American Express credit cards have a four-digit number printed on the front of the card, above the account number.