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 <monospace xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DFS_DESYNCH</monospace> database<xref ref-type="fn" rid="fn1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¹</xref><fn id="fn1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><label>¹</label> <uri>https://github.com/hardware-fab/DLaTA</uri> </fn> containing the first set of real-world highly desynchronized power traces from the execution of a software AES cryptosystem.