Protection method and device against a side-channel analysis

A circuit comprising:

• a first circuit part implementing a first operation;
• and
• a second circuit part implementing a second operation,
• the circuit configured to:
• execute the first operation, the first operation being configured to process an input data, the circuit incidentally producing during an execution of the first operation a first signal in the form of first electromagnetic radiation or a first power consumption signal, and
• execute the second operation between a first instant and a second instant during the execution of the first operation to protect the circuit against side channel analysis, the execution of the second operation being based on the input data, the circuit producing, during the execution of the second operation, a second signal in the form of second electromagnetic radiation or a second power consumption signal, the second signal being continuous, different from the first signal and mixing with the first signal between the first instant and the second instant to produce a resultant signal,
• wherein the resultant signal is measurable from outside of the circuit as a resultant power consumption signal or resultant electromagnetic radiation, the first signal being indistinctly measurable within the resultant signal, the second signal and the resultant signal varying as a function of the input data.

A device including a circuit arranged on a medium, the circuit including a first circuit part implementing a first operation and a second circuit part implementing a second operation, the circuit being configured to:

• execute the first operation, the first operation being configured to process an input data, the circuit incidentally producing, during an execution of the first operation, a first signal in the form of first electromagnetic radiation or a first power consumption signal;
• and
• execute the second operation between a first instant and a second instant during the execution of the first operation to protect the circuit against side channel analysis, the execution of the second operation being based on the input data, the circuit producing, during the execution of the second operation, a second signal in the form of second electromagnetic radiation or a second power consumption signal, the second signal being continuous, different from the first signal, and mixing with the first signal between the first instant and the second instant to produce a resultant signal,
• wherein the resultant signal is measurable from outside of the circuit as a resultant power consumption signal or resultant electromagnetic radiation, the first signal being indistinctly measurable within the resultant signal, the second signal and the resultant signal varying as a function of the input data.

A non-transitory computer-readable medium storing code portions which, when executed by a circuit, cause the circuit to:

• execute a first operation, the first operation being configured to process an input data, the circuit incidentally producing, during an execution of the first operation, a first signal in the form of first electromagnetic radiation or a first power consumption signal;
• and
• execute a second operation between a first instant and a second instant during the execution of the first operation to protect the circuit against side channel analysis, the execution of the second operation being based on the input data, the circuit producing, during the execution of the second operation, a second signal in the form of second electromagnetic radiation or a second power consumption signal, the second signal being continuous, different from the first signal, and mixing with the first signal between the first instant and the second instant to produce a resultant signal,
• wherein the resultant signal is measurable from outside of the circuit as a resultant power consumption signal or resultant electromagnetic radiation, the first signal being indistinctly measurable within the resultant signal, the second signal and the resultant signal varying as a function of the input data.