Universal fully-integrated fault attack sensor.
In cryptography, an attack can be performed by injecting one or several faults into a device thus disrupting the functional behavior of the device. Techniques commonly used to inject faults consist in introducing variations in the source voltage, clock frequency, temperature, or irradiating with a laser beam etc.
Unlike analog sensors which are dedicated to the detection of a specific perturbation attack, the Digital Sensor is designed to detect various threats belonging to the family of Fault Injection Attacks (FIA):
- Input clock frequency (clock glitches, Overclocking): reduction of the clock period to provoke a critical path violation.
- Input voltage (power glitches, underfeeding): reduction of supply voltage to increase the propagation delay of combinational logic.
- Temperature (heating): modification of the temperature to increase the propagation delay.
- Radiations (laser spot, light spot, Electromagnetic): provoke bit set or reset in registers by irradiation.
Digital Sensor converts all monitored stresses into a timing stress which is then measured. When a threat is detected, it provides the system with a measurement of the threat's level and it raises the hardware alarm.