Analysis of Electromagnetic Information Leakage from Overdesigned Power Delivery Network of Cryptographic Devices

In this paper, an analysis of electromagnetic (EM) information leakage from an overdesigned power delivery network (PDN) of cryptographic devices is presented. In the target hierarchical PDN, sufficient decoupling capacitors are mounted in both on-chip and printed circuit board (PCB) PDNs which maintained the hierarchical PDN impedance below a target impedance from 1 MHz to 1 GHz. Correlation electromagnetic analysis (CEMA) and secret key extraction are conducted based on measured electric and magnetic field radiations from various locations in the hierarchical PDN such as above chip, PCB PDN, and decoupling capacitors. For the first time, it is verified that a cryptographic device complying with the target impedance specification with a sufficient impedance margin can leak full-byte secret key information via EM field radiation. Based on the analysis result, the PDN design methodology for the cryptographic device is presented.