Towards Security Limits of Side-Channel Attacks

Abstract. This paper considers a recently introduced framework for the analysis of physically observable implementations. It exploits a model of computation that allows quantifying the effect of practically relevant leakage functions with a combination of security and information theoretic metrics. As a result of these metrics, a unified evaluation methodology was derived that we illustrate by applying it 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 about the respective effectiveness of these countermeasures (that could not be captured without our metrics). Finally, we justify the need of combined metrics for the evaluation, comparison and understanding of side-channel attacks.