Detection of IEMI fault injection using voltage monitor constructed with fully digital circuit

A threat to intentionally induce electromagnetic waves inside the cryptographic integrated circuit (IC) exists, which may cause temporary faults in processing inside the IC to acquire a secret key. We propose a method of suppressing leakage of the secret key to protect equipment from such attacks by monitoring the interfering wave inside the IC. In the proposed method, voltage variations in the amplitude and time inside the IC are measured, and an attack is detected. Further, to cheaply and easily implement the proposed method, the monitor consists of a fully digital circuit.