The card security code is a unique three or four-digit number printed on your debit/credit card. This number is not embossed on the card and hence not printed on receipts - making it difficult for anyone other than the genuine cardholder, to know it. Some card issuers refer to this number as the 'Card Security Code' others as the 'personal security code' and others as 'Card Verification Value'.

Almost all credit cards now have a three-digit number printed at the top of the signature strip on the reverse of the card. Sometimes this 3 digit number will appear at the end of the credit card number.