Card Security Code
            American Express            Visa/MC/Discover

        On American Express cards, the security
        code is four digits above your account number on the front
        of the card.
        
        
        On Visa, MasterCard and Discover cards, 
        the security code is the last three digits inside the signature strip 
        on the back of the card.
        
        The Security Code is not saved it is only used to request validation from the card issuer.