Self-dual codes, subcode structures, and applications.

The classification of self-dual codes has been an extremely active area in coding theory since 1972 [33]. A particularly interesting class of self-dual codes is those of Type II which have high minimum distance (called extremal or near-extremal). It is notable that this class of codes contains famous unique codes: the extended Hamming [8,4,4] code, the extended Golay [24,12,8] code, and the extended quadratic residue [48,24,12] code. We examine the subcode structures of Type II codes for lengths up to 24, extremal Type II codes of length 32, and give partial results on the extended quadratic residue [48,24,12] code. We also develop a generalization of self-dual codes to Network Coding Theory and give some results on existence of self-dual network codes with largest minimum distance for lengths up to 10. Complementary Information Set (CIS for short) codes, a class of classical codes recently developed in [7], have important applications to Cryptography. CIS codes contain self-dual codes as a subclass. We give a new classification result for CIS codes of length 14 and a partial result for length 16

Leakage Squeezing Countermeasure against High-Order Attacks

Part 6: Security and CryptographyInternational audienceIn the recent years, side channel attacks have been widely investigated. In particular, second order attacks (2O-attacks) have been improved and successfully applied to break many masked implementations. In this context we propose a new concept to hinder attacks of all order: instead of injecting more entropy, we make the most of a single-mask entropy. With specially crafted bijections instantiated on the mask path, we manage to reduce the inter-class variance (method we call “leakage squeezing”) so that the leakage distributions become almost independent from the processed data. We present two options for this countermeasure. The first one is based on a recoded memory with a size squared w.r.t. the unprotected requirement, whilst the second one is an enhancement alleviating the requirement for a large memory. We theoretically prove the robustness of those implementations and practically evaluate their security improvements. This is attested by a robustness evaluation based on an information theoretic framework and by a 2O-DPA, an EPA and a multi-variate mutual information analysis (MMIA) attack metric. As opposed to software-oriented 3O-DPA-proof countermeasures that seriously impact the performances, our is hardware-oriented and keeps a complexity similar to that of a standard 2O-attack countermeasure with an almost untouched throughput, which is a predominant feature in computing-intensive applications