Paper 2025/1344

Side-Channel Sensitivity Analysis on HQC: Towards a Fully Masked Implementation

Guillaume Goy, XLIM
Maxime Spyropoulos, Laboratoire Traitement et Communication de l’Information, Thales (France)
Nicolas Aragon, XLIM
Philippe Gaborit, XLIM
Renaud Pacalet, Laboratoire Traitement et Communication de l’Information
Fabrice Perion, Thales (France)
Laurent Sauvage, Laboratoire Traitement et Communication de l’Information
David Vigilant, Thales (France)
Abstract

Hamming Quasi-Cyclic (HQC) has recently been officially selected for standardization by NIST as a post-quantum KEM alternative to ML-KEM. This milestone raises new requirements, in particular the need to design and deploy secure implementations of the scheme. This paper presents two major contributions to secure HQC against Side-Channel Attacks (SCAs). First, we present a detailed sensitivity analysis of HQC, highlighting the critical variables and critical internal functions that need to be protected. Second and main contribution, we propose the first fully masked HQC implementation at any order. It is also the first PQC masked implementation that is formally proved to be secure in the MIMO-SNI security model. This security, introduced by Cassiers and Standaert in 2020, ensures the security of gadgets composition against propagating probes. In this paper, we provide benchmarks of our implementation, showing that our masked implementation is competitive in the state-of-the-art masked PQC implementations.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
Preprint.
Keywords
Hamming Quasi-CyclicSide-Channel AttackSensitivity analysisMasked implementation
Contact author(s)
guillaume goy @ unilim fr
maxime spyropoulos @ telecom-paris fr
nicolas aragon @ unilim fr
gaborit @ unilim fr
renaud pacalet @ telecom-paris fr
fabrice perion @ thalesgroup com
laurent sauvage @ telecom-paris fr
david vigilant @ thalesgroup com
History
2025-07-23: approved
2025-07-23: received
See all versions
Short URL
https://ia.cr/2025/1344
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/1344,
      author = {Guillaume Goy and Maxime Spyropoulos and Nicolas Aragon and Philippe Gaborit and Renaud Pacalet and Fabrice Perion and Laurent Sauvage and David Vigilant},
      title = {Side-Channel Sensitivity Analysis on {HQC}: Towards a Fully Masked Implementation},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1344},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1344}
}
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