Patent ID: 8527427

Claim:
A method for authorizing a transaction between an account holder and a merchant over a transaction network employing an ISO 8583 standardized message format having a data portion reserved for a static PIN, comprising: providing an account holder with access to a code generating device; generating by said code generating device a dynamic code, said dynamic code being generated based on a value that changes before a new transaction and said dynamic code is insertable in said data portion reserved for said static PIN; receiving, at a PIN processing system comprising a static PIN authentication system and a dynamic code authentication system, a transaction message in said message format, said message including one of the static PIN or the dynamic code; determining, based on the transaction message, whether the received transaction message includes the static PIN or the dynamic code; in response to determining that the transaction message includes the dynamic code, generating by said dynamic code authentication system an expected dynamic code; comparing, by said dynamic code authentication system, the received dynamic code to the generated expected dynamic code; and authorizing the transaction in response to the comparing step.