Where do I find my "Credit Card Security Code"?
Visa, Mastercard, and Discover Users
Flip your card over and look at the signture box. 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 Credit Card Security Code.
American Express Credit Card Users
Look for the 4-digit code printed on the front of your card just above and to the right of your main credit card number. This 4-digit code is your Credit Card Security Code.