1. A method of commerce over the internet between a user computer and a merchant computer, the user computer reading a document including an embedded watermark, said method comprising the steps of: at the user computer, extracting identifying data from the watermark, and passing the identifying data to a central computer; at the central computer, identifying a financial institution identifier associated with the document and passing the identifier and a session ticket to the user computer; contacting the financial institution via the financial institution identifier and passing to the financial institution the session ticket to obtain an authentication ticket; passing the authentication ticket from the user to the merchant computer to facilitate a transaction; and providing the authentication ticket from the merchant computer to the financial institution.