Morpho

Michael Barthe

Mael Berthier

Geoffrey Spinau

A smart card compares an object identification parameter associated with a write command with an object identification parameter stored in the non-volatile memory of the smart card. If the comparison is positive, the data embedded in the write command is written at a at a predefined address whose value is stored in the non-volatile memory, an address corresponding to the sum of the stored predefined address and the size of the written data is calculated, and the calculated address is stored in the non-volatile memory in place of the predefined address. If the comparison is negative, the data is written at a default address, an address corresponding to the sum of the default address and the size of the written data is calculated, and the calculated address is stored in the non-volatile memory as the predefined address.

Writing data in a non-volatile memory of a smart card

The invention relates to a method for masking the end-of-life transition of an electronic microprocessor device comprising a reprogrammable non-volatile memory containing an end-of-life state variable (FdVE). The value of the variable (FdVE) is loaded (A) into random access memory. Prior to the execution of any current command (COM), the value of the variable (FdVR) in random access memory is checked (B). The end-of-life transition is executed (C) in the event of an empty value. Otherwise, the initialization or the execution of the command (COM) is continued (D). Upon detection (E) of an intrusive attack, the end-of-life state variable (FdVR) is written (F) in the single random-access memory, and the end-of-life state variable (FdVE) is deleted (G) from the non-volatile memory in a delayed manner. The invention is suitable for all electronic devices, microprocessor cards or the like.

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Paris, France

Michael Barthe