What is a security code?

A security code is a unique three- or four-digit number printed on the back of a credit or debit card, usually appearing to the right of the signature strip. However, on some cards, the security code is on the front above the credit card number.

Other names commonly used to refer to security codes include card-verification data, card-verification number, card-verification value, card-verification code and signature-panel code. Security codes are used to confirm that the card number quoted to a merchant is acquired from an authorized credit or debit card, providing merchants and consumers with a greater level of protection against fraud.