Improving the Fault Robustness of Polynomial Masking

Paula Arnold; Sebastian Berndt; Thomas Eisenbarth; Sebastian Faust; Marc Gourjon; Elena Micheli; Maximilian Orlt; Pajam Pauls; Kathrin Wirschem; Liang Zhao

Paper 2025/1275

Improving the Fault Robustness of Polynomial Masking

Paula Arnold

, University of Lübeck

Sebastian Berndt

, Technische Hochschule Lübeck

Thomas Eisenbarth

, University of Lübeck

Sebastian Faust

, TU Darmstadt

Marc Gourjon

, Max Planck Institute for Security and Privacy

Elena Micheli, TU Darmstadt

Maximilian Orlt

, TU Darmstadt

Pajam Pauls

, University of Lübeck

Kathrin Wirschem

, TU Darmstadt

Liang Zhao

, TU Darmstadt

Abstract

Rigorous protection against physical attacks which simultaneously and adaptively combine passive side-channel observations with active fault injections is an active and recent area of research. At CRYPTO 2023, Berndt et al. presented the “LaOla” scheme for protecting arbitrary circuits against said attacks. Their constructions use polynomial masking in an optimal least number of shares and come with security proofs based on formal notions of security. In this work, we improve the security of this construction significantly by adapting it. We present a new refresh gadget designed specifically for combined attacks. This gadget does not only counteract passive side-channel attacks but additionally randomizes the effect of faults in a detectable but secret-independent manner. We introduce sufficient and attainable security definitions which are stronger than in the work of Berndt et al. to achieve this. Further, we apply the principle to the LaOla construction and prove the stronger security notions for the adapted multiplication gadget, as well as the original properties of composability and strong security against adaptive attacks combining side-channel and faults.

Metadata

Available format(s): PDF
Category: Implementation
Publication info: Preprint.
Keywords: combined attack polynomial masking probing faults
Contact author(s): p arnold @ uni-luebeck de
sebastian berndt @ th-luebeck de
thomas eisenbarth @ uni-luebeck de
sebastian faust @ tu-darmstadt de
marc gourjon @ mpi-sp org
elena micheli @ tu-darmstadt de
maximilian orlt @ tu-darmstadt de
p pauls @ uni-luebeck de
kathrin wirschem @ tu-darmstadt de
liang zhao @ tu-darmstadt de
History: 2025-07-11: approved; 2025-07-11: received; See all versions
Short URL: https://ia.cr/2025/1275
License: CC BY

BibTeX

@misc{cryptoeprint:2025/1275,
      author = {Paula Arnold and Sebastian Berndt and Thomas Eisenbarth and Sebastian Faust and Marc Gourjon and Elena Micheli and Maximilian Orlt and Pajam Pauls and Kathrin Wirschem and Liang Zhao},
      title = {Improving the Fault Robustness of Polynomial Masking},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1275},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1275}
}