PG-CAS: Pro-Active EM-SCA Probe Detection Using Switched-Capacitor-Based Patterned-Ground Co-Planar Capacitive Asymmetry Sensing

This paper presents the design and analysis of a pro-active strategy to detect the presence of an electromagnetic (EM) side-channel analysis (SCA) attack, using Patterned-Ground co-planar Capacitive Asymmetry Sensing (PG-CAS) system. The PG-CAS system senses the asymmetry created in the plate-ground capacitance and turns on a SCA countermeasure in presence of an EM probe. The proposed PG-CAS system for approaching probe consists of the EM SCA detection sensor plate and circuits. The EM SCA detection sensor is implemented as a grid of four metal plates of the same dimensions using the top metal layer along with a patterned-ground plane at the immediate lower metal layer. The EM SCA detection system consists of a proximity to capacitance conversion circuit, digital synchronization logic circuit to detect and alarm the IC, and an EM SCA countermeasure. When an attack is detected, the countermeasure is turned on based on the deviation of the symmetry of the plate-ground capacitance pairs. The PG-CAS system-level post-layout simulation results using TSMC 65nm technology and Ansys Maxwell show a $>5\times $ improvement in the detection range and a $\sim 29\times $ improvement in power consumption over existing inductive sensing methods for attack detection.