Security Code  

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.

Some cards have a three-digit number printed at the top of the signature strip on the reverse of the card.

Others, American Express cards for example, have a four-digit number printed on the front of the card, above the account number.