Citation: Wei Cheng, Sylvain Guilley, Claude Carlet, Jean-Luc Danger, Alexander Schaub. Optimal Codes for Inner Product Masking. 2019 Cryptographic Architectures Embedded in Logic Devices (CryptArchi 2019), Prague, Czech, Jun. 24-25, 2019. [Abstract, Slides]
Masking is the most popular countermeasure to protect cryptographic implementations against side-channel analysis, since it is provable secure and can be deployed at algorithm level. To strengthen the original Boolean masking scheme, several works have suggested to use more complicated schemes with high algebraic complexity, like affine masking and polynomial masking. Therefore, the Inner Product Masking (IPM) was proposed to be a better alternative with its intrinsic algebraic complexity. In this work, we express the security order of generalized IPM schemes from the viewpoint of coding theory, which allows us to optimize it. Specifically, we highlight first that the IPM scheme is not optimal by showing different security order in byte- and bit-level, respectively. In particular, this result confirms the previous observations made by Balasch et al. at EUROCRYPT’ 15 and at ASIACRYPT’ 17 and Poussier et al. at CARDIS’ 17 regarding the parameters effect in IPM.