A system for making a purchase by a customer from a merchant, wherein an electronic message represents an instruction for payment from an account with a financial institution, includes a method of: associating a public key with identity information regarding the account; receiving by the merchant both...http://www.google.de/patents/US20020112160?utm_source=gb-gplus-sharePatent US20020112160 - Three Party Account Authority Digital Signature (AADS) System 
