Application Agnostic EM Side-Channel Emanations of the FPGA Clock Distribution Network

2026-09-27

AI Summary

This study addresses the limitation of conventional electromagnetic side-channel attacks that rely on static hardware assumptions and consequently fail under dynamic FPGA configurations. To overcome this, the work proposes an application-agnostic electromagnetic side-channel analysis method for FPGAs. By modeling clock networks through deterministic finite state machines and integrating statistical analyses of mean and variance differences with grid-based sampling techniques, it systematically reveals how placement, routing, and frequency influence electromagnetic emissions. This approach effectively circumvents the constraints of static hardware assumptions. Experimental results demonstrate that as clock resource utilization increases from 25% to 90%, the number of labeled high-electromagnetic-activity grid points rises by factors of 1.32 and 1.39, respectively, thereby validating the effectiveness of the proposed methodology.

Abstract

Electromagnetic side channels have been extensively utilized in non-invasive attacks or analyses to extract critical information from deployed systems. Most of the attacks or analyses are typically executed on cryptographic algorithms under the assumption that the underlying implementation remains fixed. The assumption is valid in the context of fixed hardware, where modifications to the circuit are not made after manufacturing. However, in the case of adaptive hardware, including field-programmable gate arrays (FPGAs), the assumption no longer holds as modifications to the configuration of the array are permitted post-manufacturing. Consequently, this study introduces a methodology for the analysis of electromagnetic side channels of an FPGA through the study of deterministic finite state machines (DFSMs), where the effects of placement, routing, and operating frequency on the EM emanations of the FPGA due to the utilized clocking resources are characterized. To analyze the impact of frequency, device placement, and resource allocation on the EM emanations from the FPGA, statistical analysis including mean difference and variance difference calculations of measured EM fields were utilized to identify points of high EM activity on a set grid of sampled points. A 1.32x increase in flagged grid points was observed in the analysis of the mean difference when the percentage of utilized clock resources was increased from 25% to 90%. Similarly, a 1.39x increase in flagged grid points was observed when the variance difference was calculated for the same increase in clock resources.

Problem

• Electromagnetic side channel
• FPGA
• Clock distribution network
• Application agnostic emanations

Innovation

• Electromagnetic side channels
• FPGA
• Clock distribution network
• Deterministic finite state machines
• Statistical analysis