Templates vs. Stochastic Methods

Benedikt Gierlichs, Kerstin Lemke-Rust, Chris­tof Paar

Cryptographic Hardware and Embedded Systems - CHES 2006, 8th International Workshop, Yokohama, Japan, Oktober 10 - 13, 2006.


Template Attacks and the Stochastic Model provide advanced methods for side channel cryptanalysis that make use of `a-priori' know- ledge gained from a pro ling step. For a systematic comparison of Tem- plate Attacks and the Stochastic Model, we use two sets of measurement data that originate from two di erent microcontrollers and setups. Our main contribution is to capture performance aspects against crucial pa- rameters such as the number of measurements available during pro ling and classi cation. Moreover, optimization techniques are evaluated for both methods under consideration. Especially for a low number of mea- surements and noisy samples, the use of a T-Test based algorithm for the choice of relevant instants can lead to signi cant performance gains. As a main result, T-Test based Templates are the method of choice if a high number of samples is available for pro ling. However, in case of a low number of samples for pro ling, stochastic methods are an alter- native and can reach superior eciency both in terms of pro ling and classi cation.