Towards Security Limits in Side-Channel Attacks

In this paper, we consider a recently introduced framework that investigates physically observable implementations from a theoretical point of view. The model allows quantifying the effect of practically relevant leakage functions with a combination of security and information theoretic metrics. More specifically, we apply our evaluation methodology to an exemplary block cipher. We first consider a Hamming weight leakage function and evaluate the efficiency of two commonly investigated countermeasures, namely noise addition and masking. Then, we show that the proposed methodology allows capturing certain non-trivial intuitions, e.g. about the respective effectiveness of these countermeasures. Finally, we justify the need of combined metrics for the evaluation, comparison and understanding of side-channel attacks.