Regularizers to the rescue: fighting overfitting in deep learning-based side-channel analysis

Despite considerable achievements of deep learning-based side-channel analysis, overfitting represents a significant obstacle in finding optimized neural network models. This issue is not unique to the side-channel domain. Regularization techniques are popular solutions to overfitting and have long been used in various domains. At the same time, the works in the side-channel domain show sporadic utilization of regularization techniques. What is more, no systematic study investigates these techniques’ effectiveness. In this paper, we aim to investigate the regularization effectiveness on a randomly selected model, by applying 4 powerful and easy-to-use regularization techniques to 8 combinations of datasets, leakage models, and deep learning topologies. The investigated techniques are L₁, L₂, dropout, and early stopping. Our results show that while all these techniques can improve performance in many cases, L₁ and L₂ are the most effective. Finally, if training time matters, early stopping is the best technique.