A “Card Verification Value” (or “CVV”) is an authentication number established by prepaid debit card companies to further efforts towards reducing fraud for internet transactions. Many online transactions ask for the “security code” or “CVV” code in a check out form. You can find the CVV code on the back of your prepaid debit card (for Visa or MasterCard debit cards) and on the front of your American Express prepaid card.
The CVV code helps prove that the customer placing the order actually possesses the prepaid debit card and that the card account is legitimate. Each credit card company has its own name for the CVV code, but it functions the same for all major card types. (VISA refers to the code as CVV2, MasterCard calls it CVC2, and American Express calls it CID.)