Combining Leakage-Resilient PRFs and Shuffling (Towards Bounded Security for Small Embedded Devices).
Vincent Grosso, Romain Poussier, François‐Xavier Standaert, Lubos Gaspar · 2014
Abstract. Combining countermeasures is usually assumed to be the best way to protect embedded devices against side-channel attacks. These combinations are at least expected to increase the number of measure-ments of successful attacks to some reasonable extent, and at best to guarantee a bounded time complexity independent of the number of mea-surements. This latter guarantee, only possible in the context of leakage-resilient constructions, was only reached either for stateful (pseudo-random generator) constructions, or large parallel implementations so far. In this paper, we describe a first proposal of stateless (pseudo-random function) construction, for which we have strong hints that security bounded im-plementations are reachable under the constraints of small embedded devices. Our proposal essentially combines the well-known shuffling coun-termeasure with a tweaked pseudo-random function introduced at CHES 2012. We first detail is performances. Then we analyze it against standard differential power analysis and discuss the different parameters influenc-ing its security bounds. Finally, we put forward that its implementation in 8-bit microcontrollers can provide a better security vs. performance tradeoff than state-of-the art (combinations of) countermeasures. 1