Analysis of Filtering Window Impacts on Estimation Accuracy of Information Leakage from Exposed Power Delivery Network of Cryptographic Devices

In this paper, an analysis of filtering window impacts on estimation accuracy of electromagnetic (EM) information leakage from exposed areas in power delivery network (PDN) of cryptographic devices is presented. There are exposed areas in the PDN such as decoupling capacitors, through via plating, and small power/ground interconnections where full-byte secret key information can be leaked in the form of EM fields. Various waveforms are measured using EM field probes on the PDN of the target cryptographic device. Correlation electromagnetic analysis (CEMA), field distribution analysis, and secret key extraction are conducted based on the measured waveforms via EM field radiation from the exposed PDN. It is verified that adopting a proper filtering window to remove impacts of noise irrelevant to secret key processing is important for an accurate and efficient estimation of the information leakage from the PDN. Based on the experiment and analysis results, an efficient leakage location detection method using the filtered waveforms is discussed.