Abstract: Multiple secure transactions are provided through use of a method that uses customer one-time unique purchase order numbers (“Coupons”) generated by an algorithm that uses a permutated user key and a user insertion key as input variables. A user key (such as a Personal Identification Number, or “PIN”) is combined with a permutation variable that is correlated with a customer sequence number to create the permutated user key. A random number generator is used to generate the user insertion key correlated with the customer sequence number. The algorithm can insert the permutated user key into a user account number through use of the user insertion key. A Coupon is validated by confirming that it is contained in a set of money source Coupons generated by a money source using the user key and a random number generator that is synchronized with the random number used to generate Coupons.

Abstract: A user can customize use of a payment card, which can be an electronic card, by selecting either a first or a second user key as a selected user key. The selected user key is entered into a card number generator that uses it and a user sequence number to generate a user payment card number that differs for each transaction through use of an algorithm. Multiple payment card transactions can be handled differently depending upon which user key is chosen as the selected user key. Different user keys can be used for different accounts, different types of transactions, or to classify the transactions. A user can receive one bill, or multiple bills. Different levels of privacy can be accorded to transactions that use different user keys. A user may pay the issuer for increased security, or the user may be paid by the issuer to allow transaction data to be distributed to third parties.