Patent ID: 8620814

Claim:
In a system for making purchases by customers from merchants, a method comprising the steps of: (a) initially, for each of a plurality of customers, (i) associating a public key with identity information regarding an account from which payment may be made, (ii) wherein said associating is performed by or on behalf of a financial institution with which the account is maintained; and, thereafter (b) for a purchase by a particular one of the customers from a merchant, (i) receiving by the merchant both, (A) encoding information for an electronic message representing an account payment instruction, and (B) identity information; (ii) forwarding with the electronic message, to the financial institution for an account authorization, said received encoding information and said received identity information; (iii) upon receipt by the financial institution the electronic message, said forwarded encoding information, and said forwarded identity information, (A) retrieving from said associated public keys the public key that is associated with said forwarded identity information, and (B) determining a validation result as a function of the electronic message, said forwarded encoding information, and said retrieved public key and without need of a digital certificate from a certification authority; and (iv) upon successful validation, performing an account authorization.