Data handling system for smart data cards - has input of code and values to on card integrated circuit for checking to control access and use

摘要

A data card of a type used for account transactions and purchases is of a so called `smart' card form in which the card contains an integrated circuit. The integrated circuit has an input-output stage (2) and a data handling stage (1). Values can be entered (2.1) and is transferred into a buffer (1.8) where it is compared (1.7) with the previous (or old) value (1.9) held in memory (1.6). If the new value is less than the current value in memory the transaction is allowed, provided that a legitimation input is produced. This is in the form of a personal identification number. USE/ADVANTAGE - Provides multiple protections against misuse.