The present invention comprises a system and method for a customer and merchant to perform an on-line, and in some cases, real-time financial transaction from a personal computer or similar processing terminal over a public access communications network utilizing a universally acceptable electronic financial transaction instruction that debits a customer's selected account and notifies a merchant that a credit is due or forthcoming and a service provider. The financial transaction instruction is provided in a secured format for transactions sent over the public access communications network, which is external from any other conventional open or closed communication channels used for performing financial transactions.