Abstract: The invention relates to a method for testing the authenticity of a data carrier (1) and/or an external device (2) which enters into data exchange with the data carrier (1). According to the invention, the data carrier (1) and the external device (2) are each equipped with a special additional apparatus (4, 6) for generating and/or testing authenticity data. Data transmission between the data carrier (1) and the external device (2) as required for authenticity testing is performed at least partly via a special transmission channel (B). The transmission channel (B) for transmitting authenticity data is separated physically or logically from a transmission channel (A) for transmitting standard data so that there is no mutual interference of data transmission via the two transmission channels (A, B).

Abstract: The invention relates to a method for testing the authenticity of a data carrier with an integrated circuit and is characterized in that a material is provided in an area of the integrated circuit which is excited to luminesce for example by an electromagnetic radiation or by an electric field, the electromagnetic radiation emitted by the material being measured and evaluated for determining the authenticity of the data carrier.

Abstract: A system for testing the authenticity of a data carrier determines the physical property of the data carrier from an irreversibly adjustable electric state of a circuit present separately on the integrated circuit, and uses the electric property of the circuit for establishing a characteristic value for the data carrier.

Abstract: A method for testing the authenticity of a data carrier having at least an integrated circuit with memory units and logic units as well as a data line for data exchange with an external device. The invention is characterized in that the integrated circuit additionally has a separate hard-wired circuit for transmitting and/or receiving data during the power-up sequence, which is used for authenticity testing, the first transmission or reception of data being completed within a defined time domain of the power-up sequence in which the data line has no defined state.

Abstract: A data carrier having an electronic module includes an integrated circuit. The integrated circuit has not only has the usual components, but also an electronic check unit having a nonvolatile memory area and a separate interface. During normal operation of the data carrier, data are written additionally in the electronic check unit. If functional failure of the electronic module of the data carrier occurs, the data are still readable from the memory of the electronic check unit via the separate inter-face even if the integrated circuit is otherwise mechanically destroyed.