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)
  
• Input voltage (power glitches, underfeeding)
  
• Temperature (heating)
  
• Radiations (laser spot, light spot, electromagnetic)
  

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.