Where is the Credit Card Security Code?
Sample credit card back For Visa, MasterCard, and Discover, look at the signature box on the back side of the card and you should see either the entire 16-digit credit card number or just the last four digits followed by a special 3-digit code. This 3-digit code is your Card Security Code.
Sample AMEX card back For American Express, the 4-digit number is usually printed on the front of the card, above and to the right of the embossed account number. A few American Express cards print this number above and to the left of the embossed account number.

What is the Card Security Code?

The Card Security Code (CSC) is a 3 or 4 digit number separate the credit card number that helps validate that the customer using a credit card on-line actually has the credit card in possession. The CSC is only printed on the card and it is not contained in the magnetic stripe information nor does it appear on sales receipts or billing statements. This helps prevent someone who has stolen the card number but does not have the card itself from using the credit card since it provides some assurance that the physical card is in the possession of the buyer.

The CSC has been provided as an additional tool for merchants to use in reducing fraudulent credit card charges. It is intended to protect consumers and it not uncommon for it to be requested and/or required when paying by credit card on-line.

The CSC is known by different names with the different card associations. CSC is known to Visa as the Card Verification Code (CVV2); to MasterCard as the Card Validation Code (CVC2); to Discover as the Card Identification Number (CID); American Express calls it CID.