Effect of Clock Frequencies on EM Information Leakage from Cryptographic Devices

摘要

This paper focuses on clock frequency, one of the operating parameters of a cryptographic module, and evaluates its effect on the acquisition characteristics of secret key information using Correlation Power Analysis (CPA). In our experiment, we employed the Side-channel Attack Standard Evaluation Board (SASEBO-G) and measured the transient currents in a cryptographic module at varying clock frequencies used by the cryptographic module. We calculated the correlation coefficient between each transient current waveform and a hypothetical current value to reveal the effect of clock frequencies on the CPA correlation coefficients. In addition, we showed that using frequency domain CPA can be an effective method of evaluating secret key information when the clock frequency exceeds a certain value.