Masked Vector Sampling for HQC

Maxime Spyropoulos, Maxime Spyropoulos, David Vigilant, Fabrice Perion, Renaud Pacalet, Laurent Sauvage

2025

Abstract

Anticipating the advent of large quantum computers, NIST started a worldwide competition in 2016 aiming to define the next cryptographic standards. HQC is one of these post-quantum schemes selected for standardization. In 2022, Guo et al. introduced a timing attack that exploited a weakness in HQC rejection sampling function to recover its secret key in 866,000 calls to an oracle. The authors of HQC updated its specification by applying an algorithm to sample vectors in constant time. A masked implementation of this function was later proposed for BIKE but it is not directly applicable to HQC. In this paper we propose a specification-compliant masked version of the HQC vector sampling which relies, to our knowledge, on the first masked implementation of the Barrett reduction.

Paper Citation

in Harvard Style

Spyropoulos M., Vigilant D., Perion F., Pacalet R. and Sauvage L. (2025). Masked Vector Sampling for HQC. In Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT; ISBN 978-989-758-760-3, SciTePress, pages 750-758. DOI: 10.5220/0013637400003979

in Bibtex Style

@conference{secrypt25,
author={Maxime Spyropoulos and David Vigilant and Fabrice Perion and Renaud Pacalet and Laurent Sauvage},
title={Masked Vector Sampling for HQC},
booktitle={Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT},
year={2025},
pages={750-758},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013637400003979},
isbn={978-989-758-760-3},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT
TI - Masked Vector Sampling for HQC
SN - 978-989-758-760-3
AU - Spyropoulos M.
AU - Vigilant D.
AU - Perion F.
AU - Pacalet R.
AU - Sauvage L.
PY - 2025
SP - 750
EP - 758
DO - 10.5220/0013637400003979
PB - SciTePress