Whether shopping online or over the phone, you must provide your credit card information to process the transaction. Apart from entering a card number and an expiration date, you probably will have to ...

Credit card security codes are three-digit codes on the back of your card (four-digits on the front if you have an American Express card) used to verify that have the physical card. You typically ...

Most credit-card and debit-card numbers are a sequence of 16 digits, with the final number in the sequence being a “checksum,” or a calculated number that was once useful in checking that a card ...