Visa, MasterCard and Diners Club
This number is printed on your MasterCard, Visa
and Diners Club in the signature area of the
back of the card. (it is the last 3 digits after
the credit card number). If you cannot read your
card security code, please contact the issuing
creditor.
American Express
American Express cards have a 4-digit code
printed on the front side of the card above the
number (also referred to as the CID number). It
is not embossed like the card number but printed
flat.