CARD SECURITY CODE

The Card Security Code (CSC), sometimes called Card Verification Value (CVV or CV2), Card Verification Value Code (CVVC), Card Verification Code (CVC), Verification Code (V-Code or V Code), or Card Code Verification (CCV) is a security feature for credit or debit card transactions, giving increased protection against credit card fraud.There are actually several types of security codes:The first code, called CVC1 or CVV1, is encoded on the magnetic stripe of the card and used for transactions in person. The second code, and the most cited, is CVV2 or CVC2. This CSC (also known as a CCID or Credit Card ID) is often asked for by merchants for them to secure "card not present" transactions occurring over the Internet, by mail, fax or over the phone. In many countries in Western Europe, due to increased attempts at card fraud, it is now mandatory to provide this code when the cardholder is not present in person. Contactless Card and Chip cards may supply their own codes generated electronically, such as iCVV or Dynamic CVV.

The CVC should not be confused with the standard card account number appearing in embossed or printed digits. (The standard card number undergoes a separate validation algorithm called the Luhn algorithm which serves to determine whether a given card's number is appropriate.

The CVC should not be confused with PIN codes such as MasterCard SecureCode or Visa Verified by Visa. These codes are not printed or embedded in the card but are entered at the time of transaction using a keypad. The CVV2 is a 3- or 4-digit value printed on the card or signature strip, but not encoded on the magnetic stripe.

The number is generated when the card is issued, by hashing the card number and expiration date under a key known only to the issuing bank. Supplying this code in a transaction is intended to verify that the customer has the card in their possession. Knowledge of the code proves that the customer has seen the card, or has seen a record made by somebody who saw the card. To date, no cracks for this system are known.