Removing the Field Size Loss from Duc et al.’s Conjectured Bound for Masked Encodings

  • Julien Béguinot
  • , Wei Cheng
  • , Sylvain Guilley
  • , Yi Liu
  • , Loïc Masure
  • , Olivier Rioul
  • , François Xavier Standaert

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

At Eurocrypt 2015, Duc et al. conjectured that the success rate of a side-channel attack targeting an intermediate computation encoded in a linear secret-sharing, a.k.a. masking with d+ 1 shares, could be inferred by measuring the mutual information between the leakage and each share separately. This way, security bounds can be derived without having to mount the complete attack. So far, the best proven bounds for masked encodings were nearly tight with the conjecture, up to a constant factor overhead equal to the field size, which may still give loose security guarantees compared to actual attacks. In this paper, we improve upon the state-of-the-art bounds by removing the field size loss, in the cases of Boolean masking and arithmetic masking modulo a power of two. As an example, when masking in the AES field, our new bound outperforms the former ones by a factor 256. Moreover, we provide theoretical hints that similar results could hold for masking in other fields as well.

Original languageEnglish
Title of host publicationConstructive Side-Channel Analysis and Secure Design - 14th International Workshop, COSADE 2023, Proceedings
EditorsElif Bilge Kavun, Michael Pehl
PublisherSpringer Science and Business Media Deutschland GmbH
Pages86-104
Number of pages19
ISBN (Print)9783031294969
DOIs
Publication statusPublished - 1 Jan 2023
Event14th International Workshop on Constructive Side-Channel Analysis and Secure Design, COSADE 2023 - Munich, Germany
Duration: 3 Apr 20234 Apr 2023

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume13979 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference14th International Workshop on Constructive Side-Channel Analysis and Secure Design, COSADE 2023
Country/TerritoryGermany
CityMunich
Period3/04/234/04/23

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