What Is a Card Security Code on a Credit or Debit Card?

A card security code is a unique series of digits found on credit and debit cards, serving as a protective measure for financial transactions. This code acts as an additional layer of security, particularly for purchases made without the physical card being present. It helps verify that the person using the card is the legitimate cardholder, reducing the risk of unauthorized activity.

Understanding the Card Security Code

A card security code is a three or four-digit number designed to enhance the security of “card-not-present” transactions, such as those conducted online, over the phone, or through mail orders. Its primary purpose is to help prevent fraud by providing an extra verification step beyond just knowing the card number and expiration date. When you provide this code during a transaction, it helps confirm that you have physical possession of the card, making it more difficult for unauthorized individuals to use stolen card details.

Unlike the main card number, the security code is typically not embossed on the card. This code is also generally not stored by merchants after a transaction is authorized, a practice mandated by payment industry security standards like PCI DSS (Payment Card Industry Data Security Standards). This non-storage policy reduces the risk of the code being compromised in a data breach.

Locating Your Card Security Code

The placement of your card security code varies depending on the card network. For Visa, Mastercard, and Discover cards, the security code is a three-digit number located on the back of the card. It is usually found within or just to the right of the signature strip. Sometimes, the last four digits of your card number may appear before the security code, but these are not part of the security code itself.

American Express cards feature a four-digit security code, which is typically found on the front of the card. This code is usually printed above and to the right of the main card number.

Common Names for the Code

The card security code is known by several different names, depending on the card network or payment processor. Visa refers to it as the Card Verification Value (CVV) or CVV2. Mastercard uses the term Card Validation Code (CVC) or CVC2.

Discover typically calls it the Card Identification Number (CID) or Card Verification Data (CVD). American Express also uses CID, referring to its four-digit code, but may also use CSC (Card Security Code) for a three-digit code sometimes found on the back of their cards. Despite these different acronyms, they all serve the same purpose as a security feature for transactions.