Revealing side-channel issues of complex circuits by enhanced leakage models

In the light of implementation attacks a better understanding of complex circuits of security sensitive applications is an important issue. Appropriate evaluation tools and metrics are required to understand the origin of implementation flaws within the design process. The selected leakage model has significant influence on the reliability of evaluation results concerning the side-channel resistance of a cryptographic implementation. In this contribution we introduce methods, which determine the accuracy of the leakage characterization and allow to quantify the signal-to-noise ratio. This allows a quantitative assessment of the side-channel resistance of an implementation without launching an attack. We validate the conclusions drawn from our new methods by real attacks and obtain similar results. Compared to the commonly used Hamming Distance model in our experiments enhanced leakage models increased the attack efficiency by up to 500%.