The Credit Card CPC selects an encryption protocol based upon the accepted types string. The string is evaluated from left to right, comparing the payment method and protocol until a match is found.
For example, if the string "Visa:SET;Visa:Clear;MasterCard:Clear;AMEX:SET" is the accepted types string, when the user selects a Visa card, SET will be used because it is the match that is located the farthest to the left. If a MasterCard is selected, Clear will be used because it is the only protocol defined for MasterCard. If AMEX is selected, SET will be used. Matches are done left to right and the first match found is used. A merchant can move the strongest encryption protocols or preferred protocols to the left side of less preferred protocols. If the first matching protocol fails, the next matching protocol is used.