Paper 2013/608

Towards Optimal Leakage Exploitation Rate in Template Attack

Guangjun Fan and Yongbin Zhou and Hailong Zhang and Dengguo Feng

Abstract

Under the assumption that one has a reference device identical or similar to the target device, and thus be well capable of characterizing power leakages of the target device, Template Attack is widely accepted to be one of the most powerful side-channel attacks. However, the question of whether Template Attack is really optimal in terms of the leakage exploitation rate is still unclear. In this paper, we present a negative answer to this crucial question by introducing a normalization process into classical Template Attack. Specifically, our contributions are two folds. On the theoretical side, we prove that Normalized Template Attack is better in terms of the leakage exploitation rate than Template Attack; on the practical side, we evaluate the key-recovery efficiency of Normalized Template Attack and Template Attack in the same attacking scenario. Evaluation results show that, compared with Template Attack, Normalized Template Attack is more effective. We note that, the computational price of the normalization process is of extremely low, and thus it is very easy-to-implement in practice. Therefore, the normalization process should be integrated into Template Attack as a necessary step, so that one can better understand practical threats of Template Attack.