In the last decade, an effort has been made by the research community to find efficient ways to thwart side channel analysis (SCA) against physical implementations of cryptographic algorithms. A common countermeasure for implementations of block ciphers is Boolean masking which randomizes the variables to be protected by the bitwise addition of one or several random value(s). However, advanced techniques called higher-order SCA attacks exist that overcome such a countermeasure. These attacks are greatly favored by the very nature of Boolean masking. In this paper, we revisit the affine masking initially introduced by Von Willich in 2001 as an alternative to Boolean masking. We show how to apply it to AES at the cost of a small timing overhead compared to Boolean masking. We then conduct an in-depth analysis pinpointing the leakage reduction implied by affine masking. Our results clearly show that the proposed scheme provides an excellent performance-security trade-off to protect AES against higher-order SCA.
Abstract. Cryptographic algorithms embedded on physical devices are particularly vulnerable to Side Channel Analysis (SCA). The most common countermeasure for block cipher implementations is masking, which randomizes the variables to be protected by combining them with one or several random values. In this paper, we propose an original masking scheme based on Shamir's Secret Sharing scheme [22] as an alternative to Boolean masking. We detail its implementation for the AES using the same tool than Rivain and Prouff in CHES 2010 [16]: multi-party computation. We then conduct a security analysis of our scheme in order to compare it to Boolean masking. Our results show that for a given amount of noise the proposed scheme -implemented to the first orderprovides the same security level as 3 rd up to 4 th order boolean masking, together with a better efficiency.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.