CSC - Card Security Code
What is a CSC Number?
The CSC is the Card Security Code, a 3-digit or 4-digit number printed in the signature field on the back of your credit card. On some cards, the credit card number, or part of it, appears before the CSC. Because the number appears only on the card itself (not on your receipts or statements), requiring the CSC means that you must be in physical possession of the credit card you're using, which helps to protect you and us against fraud.
How to find your CSC Number.
This number is printed on your MasterCard, Visa & Discover cards in the signature area of the card. (It is the last 3 digits AFTER the credit card number in the signature area of the card). American Express customers do not need to enter a CSC Number