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, many UK-issued cards for example, 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.
Billing Address
This should be the address to which your card statement is sent. It must match the address held by your card issuer exactly. If it does not, the retailer may decline your purchase, or defer acceptance of your payment and seek further proof of your address.