Hierarchic arrangement for the verification and renewal of security date in electronic fund transfer systems

Abstract From the Canadian patent

The invention provides an electronic fund transfer and data protection system comprising; a plurality of portable data carriers; a plurality of transaction terminals; self-contained portable storage units for storing security test numbers and a list of transaction events data obtained from said transaction terminals; computer units with data storage space for receiving transaction event data from the self-contained storage units and for imparting new test numbers thereto; and an originating station where security test numbers are generated and electrically passed to the computer units via dedicated communication lines.