Side-channel information and electromagnetic leakage: investigation at a microstrip design level

Abstract: The number of IoT devices is increasing all over the world. As with any electrical device, they emit electromagnetic emissions. These emissions pose a security threat when it comes to electromagnetic side-channel attacks. This thesis will investigate the relationship between hardware interconnect designs, the emissions' strength, and side-channel contents. The research on side-channel attacks mainly focuses on decrypting encrypted information via increasingly more advanced software solutions. This thesis focuses on hardware rather than software solution for the particular case of microstrip design. Different PCB interconnect designs are tested to find the parameters impacting radiated emissions. As a test case, we use two Rpis to simulate two components with a microstrip interconnecting them. A UART protocol is used to send ASCII characters. The EM radiations are measured with an EM scanner using an E-probe. The radiated emission are post-processed and analysed using the Wilcoxon rank sum test. The final result of this thesis is that changing the three parameters, namely, the impedance, gap (distance between the ground and the conducting line), and the number of vias, reduced the average emissions by 3.701 dB$\mu$V, and the statistical difference between O and U has been removed. Therefore, this thesis shows that a tailored designed solution that reduces the radiated emissions can also reduce the side-channel content of EM radiations.