Siemens Nixdorf Informationssysteme Aktiengesellschaft

Thomas Hueske

Axel Pfau

Klaus Mueller

Hildegard Jost

Method and apparatus for preventing inadmissible deviations from the runtime protocol of an application in a data exchange system. The data exchange system has, for example, a terminal T and a chip card K. For various applications (for example, automatic teller unit, computer access), basic functions B stored in the chip card K are processed in a sequence respectively defined in a protocol. Since the basic functions B are called in proceeding from the terminal T, the data integrity could be deteriorated by intentional modifications of the protocol sequence at the terminal T. By storing the allowable protocols in a control list STL and establishing a status memory area ZS on the chip card K, it becomes possible to monitor the protocol execution on the chip card K independently of the terminal T. The respective status Z of an application is fixed in the status memory area ZS. All basic function designations Bn permitted for a status Z are deposited in the control list STL.

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Munich, Germany

Thomas Hueske