Behind the Scene of Side Channel Attacks

Abstract

Abstract. Since the introduction of side channel attacks in the nineties, a large amount of work has been devoted to their effectiveness and efficiency improvements. On the one side, general results and conclusions are drawn in theoretical frameworks, but the latter ones are often set in a too ideal context to capture the full complexity of an attack performed in real conditions. On the other side, practical improvements are proposed for specific contexts but the big picture is often put aside, which makes them difficult to adapt to different contexts. This paper tries to bridge the gap between both worlds. We specifically investigate which kind of issues is faced by a security evaluator when performing a state of the art attack. This analysis leads us to focus on the very common situation where the exact time of the sensitive processing is drown in a large number of leakage points. In this context we propose new ideas to improve the effectiveness and/or efficiency of the three considered attacks. In the particular case of stochastic attacks, we show that the existing literature, essentially developed under the assumption that the exact sensitive time is known, cannot be directly applied when the latter assumption is relaxed. To deal with this issue, we propose an improvement which makes stochastic attack a real alternative to the classical correlation power analysis. Our study is illustrated by various attack experiments performed on several copies of three micro-controllers with different CMOS technologies (respectively 350, 130 and 90 nanometers).

Template Attacks on Different Devices

“…a far-away bump in the trace not related to k can affect the leakage samples that matter most. Another possibility, to deal with the lowfrequency offset, might be to use electromagnetic leakage, as this leakage is not affected by low-frequency components, so it may provide better results [16].…”

“…However, most previous studies [2,5,8,10,17] used the same device (and possibly acquisition campaign) for the profiling and attack phases. Only recently, Renauld et al [12] performed an extensive study on 20 different devices, showing that the template attack may not work at all when the profiling and attack steps are performed on different devices; Elaabid et al [14] showed that acquisition campaigns on the same device, but conducted at different times, also lead to worse template-attack results; and Lomné et al [16] evaluated this scenario using electromagnetic leakage.…”

Side-channel leakage and trace compression using normalized inter-class variance

“…It can also be noted that NICV is considered as the relevant distinguisher for the Linear Regression Analysis (LRA) [19,22], which acts as the CPA but with a parametric leakage model. Now, if X is uniformly distributed, the NICV in itself is not a distinguisher.…”

Computational aspects of correlation power analysis

“…in [2]), Pearson's ρ has been used in almost all correlation power attacks over the last decade, since it allows for an efficient correlation computation. The work performed in [16] also investigates reducing the algorithmic complexity of various power analysis attacks. In the extended version of this work CPA is considered as well [17].…”

“…The work performed in [16] also investigates reducing the algorithmic complexity of various power analysis attacks. In the extended version of this work CPA is considered as well [17]. However, the focus is on partitioning the traces and computing statistical information on these smaller partitions (in the setting of CPA using the ideas from [15]) while this paper also tries to look into computational aspects when the number of traces and samples is fixed.…”