DEVICE FOR DETECTING ATTEMPTS AT FRAUD ON AN APPARATUS FOR READING AND WRITING ON A CHIP CARD, METHOD OF DETECTING ATTEMPTS AT FRAUD BY MEANS OF SAID DEVICE

摘要

A device for detecting attempts at fraud by varying the electrical properties of a connecting point (12) of a chip card (3) in an apparatus for reading and writing in a memory on said chip card (3) via an electric feed line (13) connected to said connecting point (12), said device comprising: a resonance unit (6) and a measuring unit (7) connected to said resonance unit (6) wherein said resonance unit (6) has a resonator (1) that is coupled to said connecting point (12), said resonance unit (6) havi ng electrical properties that are varied by said feed line (13) and detected by said measuring device (7). A method of detecting such attempts by means of said device includes: measuring impedance at the resonator (1) input and comparing thereof with a desired value of impedance which the resonator (1) has without the electric feedline (13) at the connecting point (12).