What is the CSC (CVV/CID)?
VISA/MASTERCARD/AMERICAN EXPRESS/DISCOVER

The Card Security Code (CSC) appears as the last 3 digits in the back of the credit card and is not part of the Credit Card Number. The CSC is typically in the signature field and typed in reverse italics. Some cards will show the 3 digit CSC code after the credit card's last few numbers and may not always be italicized. See above example.
This 3-digit additional value is not contained upon the magnetic stripe on the back of the card. The number appears only on the card and NOT on receipts or statements. We ask for this number because it provides some assurance that the physical card is in the possession of the owner.