Practical template-algebraic side channel attacks with extremely low data complexity

Abstract

Template-based Tolerant Algebraic Side Channel Attacks (Template-TASCA) were suggested in [20] as a way of reducing the high data complexity of template attacks by coupling them with algebraic side-channel attacks. In contrast to the maximum-likelihood method used in a standard template attack, the template-algebraic attack method uses a constraint solver to find the optimal state correlated to the measured side-channel leakage. In this work we present the first application of the template-algebraic key recovery attack to a publicly available data set (IAIK WS2). We show how our attack can successfully recover the encryption key even when the attacker has extremely limited access to the device under test -- only 200 traces in the offline phase and as little as a single trace in the online phase.