A device for selecting an operating mode of an integrated circuit,
including a non-volatile memory programmable after manufacturing
exhibiting prior to any programming an initial content, means for storing
a first signature representative of the initial content of the memory,
means for calculating a second signature representative of a current
content of the memory, and means for evaluating a difference between the
first and second signatures and for deactivating an operating mode
selection signal when the difference is greater than a predetermined
threshold.