Credit Card ID verification numbers
Credit card identification or verification numbers are part of a system devised by the credit card companies to provide another line of defense against fraudulent use of your credit card. American Express calls it the CID (Card Identification Number). For MasterCard, it is the CVC2 (Card Validation Code). Visa calls this number the CVV2 (Card Verification Value).
Your card's ID verification number is unique. Because it is printed on the card, not embossed, it is virtually impossible to replicate accurately on counterfeit or altered plastic. The ID number is used only at the point of sale and is not retained by the merchant. It has been proven that performing this verification significantly reduces credit card fraud, and therefore we are now requesting Card ID numbers for your increased protection and security.
American Express. The CID has four digits and is located on the front:
MasterCard and Visa. The three-digit number is on the back:
If your credit card does not have one of these unique ID numbers, please contact your credit card company and obtain a new one that is protected in this way. Many merchants now require the number and you will be glad to have it.