| 摘要 |
To detect passive simulators the method uses a supplementary stage to send a bit to memory and to reread the bit to check for fraud. Electronic memory phone card method of fraud detection. The card operates at a given frequency (Of). A variable frequency excitation signal (is) is applied to the card and a response motif (M) furnished by the card, at low excitation frequency, is recorded. Fraud is detected if the response motif (M) is deformed at an excitation frequency lower than the operating frequency (Of) of the card The method uses a supplementary stage to effect a write operation of at least a bit in the electronic memory in impossible write conditions, then rereads the bit so as to conclude that their is fraud in the case of a positive reread..
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