EM Side-Channel Countermeasure for Switched-Capacitor DC–DC Converters Based on Amplitude Modulation

Abstract

The security of IoT devices is becoming a major concern in industry. Noninvasive side-channel attacks pose a serious threat as they are capable of extracting secret information from distance while using low-cost equipment. In this article, we propose an efficient countermeasure technique against the electromagnetic (EM) side-channel attacks. The technique is applied to switched-capacitor (SC) dc-dc converters and is based on amplitude modulation of the load signal by the converter capacitance that acts as a carrier. We verify the proposed technique by using a reliable evaluation metric that predicts the correlation between the encryption secret key and the attacker's measured signal. The results show that the proposed technique can achieve cross correlation coefficients as low as 0.2, disabling the attacker from extracting the sensitive information. In addition, test vector leakage assessment (TVLA) ρ-test indicates that the number of leaky points for advanced encryption standard (AES) execution drops from 62 for unprotected circuit to zero for the circuit secured by the proposed technique. TVLA t-statistic is decreased by three orders of magnitude in the protected AES execution.