A Deep Learning-assisted Template Attack Against Dynamic Frequency Scaling Countermeasures

In the last decades, machine learning techniques have been extensively used in place of classical template attacks to implement profiled side-channel analysis. This manuscript focuses on the application of machine learning to counteract Dynamic Frequency Scaling defenses. While state-of-the-art attacks have shown promising results against desynchronization countermeasures, a robust attack strategy has yet to be realized. Motivated by the simplicity and effectiveness of template attacks for devices lacking desynchronization countermeasures, this work presents a Deep Learning-assisted Template Attack (DLaTA) methodology specifically designed to target highly desynchronized traces through Dynamic Frequency Scaling. A deep learning-based pre-processing step recovers information obscured by desynchronization, followed by a template attack for key extraction. Specifically, we developed a three-stage deep learning pipeline to resynchronize traces to a uniform reference clock frequency. The experimental results on the AES cryptosystem executed on a RISC-V System-on-Chip reported a Guessing Entropy equal to 1 and a Guessing Distance greater than 0.25. Results demonstrate the method's ability to successfully retrieve secret keys even in the presence of high desynchronization. As an additional contribution, we publicly release our DFS_DESYNCH database https://github.com/hardware-fab/DLaTA containing the first set of real-world highly desynchronized power traces from the execution of a software AES cryptosystem.