Visa, MasterCard, and
Flip the card over and look at the signature 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 the Card Security Code.
American Express Users
Look for the 4-digit code printed on the front of the card just above and to
the right of the main credit card number. This 4-digit code is the Card