Thwarting Higher-Order Side Channel Analysis with Additive and Multiplicative Maskings.
Résumé
Higher-order side channel attacks is a class of powerful techniques against cryptographic implementations. Their complexity grows exponentially with the order, but for small orders (e.g. 2 and 3) recent studies have demonstrated that they pose a serious threat in practice. In this context, it is today of great importance to design software countermeasures enabling to counteract higher-order side channel attacks for any arbitrary chosen order. At CHES 2010, Rivain and Prouff have introduced such a countermeasure for the AES. It works for any arbitrary chosen order and benefits from a formal resistance proof. Until now, it was the single one with such assets. By generalizing at any order a countermeasure introduced at ACNS 2010 by Genelle etal., we propose in this paper an alternative to Rivain and Prouff's solution. The new scheme can also be proven secure at any order and has the advantage of being at least 2 times more efficient than the existing solutions for orders 2 and 3, while maintaining the RAM consumption lower than 200 bytes.