A method in an elliptic curve cryptographic system, the method being executed by an electronic device and including a multiplication operation of multiplying a point of an elliptic curve by a scalar number, the point having affine coordinates belonging to a Galois field, the multiplication operation including steps of detecting the appearance of a point at infinity during intermediate calculations of the multiplication operation, and of activating an error signal if the point at infinity is detected and if the number of bits of the scalar number processed by the multiplication operation is lower than the rank of the most significant bit of an order of a base point of the cryptographic system.

There is provided a device of protecting an Integrated Circuit from perturbation attacks. The device includes a sensing unit configured to detect a perturbation attack, the sensing unit comprising a set of digital sensors comprising at least two sensors, the sensors being arranged in parallel. Each digital sensor provides a digitized bit output having a binary value, in response to input data, the sensing unit being configured to deliver at least one binary vector comprising a multi-bit value, the multi-bit value comprising at least two bit outputs provided by the set of digital sensors. The sensing device further comprising an analysis unit, the analysis unit being configured to receive at least one binary vector provided by the sensing unit, the analysis unit being configured to detect a perturbation attack from the at least one binary vector.

There is provided a device of protecting an Integrated Circuit from perturbation attacks. The device includes a sensing unit configured to detect a perturbation attack, the sensing unit comprising a set of digital sensors comprising at least two sensors, the sensors being arranged in parallel. Each digital sensor provides a digitized bit output having a binary value, in response to input data, the sensing unit being configured to deliver at least one binary vector comprising a multi-bit value, the multi-bit value comprising at least two bit outputs provided by the set of digital sensors. The sensing device further comprising an analysis unit, the analysis unit being configured to receive at least one binary vector provided by the sensing unit, the analysis unit being configured to detect a perturbation attack from the at least one binary vector.

This disclosure relates to a method for securing the execution of a program by a processor, including a comparison instruction for comparing two data items, followed by a program operation which is selected as a function of a comparison result provided by the comparison instruction. The method may include, before the execution of the comparison instruction, calculating in various ways comparison data representative of the equality of the data to be compared, after the execution of the comparison instruction, verifying whether the comparison data calculated are consistent with the fact that the program operation is selected or not selected, and activating an error signal if the comparison data are mutually inconsistent or inconsistent with the result of the comparison.

The present description concerns a method of checking a first data element, executed by an electronic device comprising a processor and a memory, wherein said first data element is not stored in said memory and is divided in N second data elements independent from the first data element, each second data element being stored in said memory, and a result of an application of a XOR function to the N second elements being equal to the first data element, wherein an image of the first data element by a CRC function linear with respect to the XOR function is stored in said memory, and said method comprising a step, executed by said processor, of checking if said image of the first data element by said CRC function is equal to an application of the XOR function to the images of N second elements by said CRC function.

This disclosure relates to a method for securing the execution of a program by a processor, including a comparison instruction for comparing two data items, followed by a program operation which is selected as a function of a comparison result provided by the comparison instruction. The method may include, before the execution of the comparison instruction, calculating in various ways comparison data representative of the equality of the data to be compared, after the execution of the comparison instruction, verifying whether the comparison data calculated are consistent with the fact that the program operation is selected or not selected, and activating an error signal if the comparison data are mutually inconsistent or inconsistent with the result of the comparison.