Electromagnetic fault injection: the curse of flip-flops

Electromagnetic (EM) waves have been recently pointed out as a medium for fault injection within integrated circuits (IC). Indeed, it has been experimentally demonstrated that an EM pulse (EMP), produced with a high-voltage pulse generator and an injector similar to that used to perform EM analyses, was susceptible to create faults exploitable from a cryptanalysis viewpoint. An analysis of the induced faults revealed that they originated from timing constraint violations. In this context, this paper demonstrates that EM injection, performed with enhanced injectors, can produce not only timing faults but also bit-set and bit-reset faults on an IC at rest. This first result clearly extends the range of the threats associated with EM fault injection. It then demonstrates, considering two different ICs under operation: an FPGA and a modern microcontroller, that faults produced by EMP injection are not timing faults but correspond to a different model which is presented in this paper. This model allows to explain experimental results introduced in all former communications.