Credit cards use security codes to verify identity and protect against card fraud. In some purchases, the verification process gathers codes automatically from encrypted data on the card. If you're making a card-not-present transaction over the Internet or phone, you provide an additional security code, or CV2 number. The CV2 is series of three or four numbers that can be printed on either side of the card.
Credit Card Security Codes
If you're paying by credit card in person, the transaction checks a validation code encrypted on the card's magnetic stripe or chip as part of the approval process. This code has various names, including CVC, CVC1, CVV or CVV1. The code is checked automatically, and you don't know its data.
If you're buying online or by phone, merchants or websites can't physically check stripes or chips. Therefore, remote transactions use a different security code, the CV2, CVV2 or CVC2. This code is a series of numbers printed on the credit card. You provide the code number when prompted during the payment process to prove that you have the card in your possession.
Finding the Number
CV2 codes are not embossed but are printed. Typically, the code has three digits and is printed on the back of the credit card at the end of a series of numbers. It may appear on or above the signature line or in a separate box somewhere else on the back. American Express is an exception to this rule. It prints CV2 codes on the front of its credit cards above the card number and uses four digits.