Paper 2025/839
Correlation power analysis of LESS and CROSS
, Graz University of Technology, Graz University of Technology, Graz University of TechnologyAbstract
This paper presents a side-channel attack targeting the LESS and CROSS post-quantum digital signature schemes, resulting in full key recovery for both. These schemes have advanced to the second round of NIST’s call for additional signatures. By leveraging correlation power analysis and horizontal attacks, we are able to recover the secret key by observing the power consumption during the multiplication of an ephemeral secret vector with a public matrix. The attack path is enabled by the presence of a direct link between the secret key elements and the ephemeral secret, given correct responses. This attack targets version 1.2 of both schemes. In both settings we can recover the secret key in a single trace for the NIST’s security level I parameter set. Additionally, we propose improvements to the existing horizontal attack on CROSS, reducing the required rounds that need to be observed by an order of magnitude for the same parameter sets.
Note: To appear in Africacrypt 2025.
Metadata
- Available format(s)
-
PDF
- Category
- Attacks and cryptanalysis
- Publication info
- Published elsewhere. Africacrypt 2025
- Keywords
- Side-channel attacksPost-quantum cryptographyCROSSLESS
- Contact author(s)
-
maciej czuprynko @ tugraz at
anisha mukherjee @ tugraz at
sujoy sinharoy @ tugraz at - History
- 2025-05-12: approved
- 2025-05-12: received
- See all versions
- Short URL
- https://ia.cr/2025/839
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2025/839,
author = {Maciej Czuprynko and Anisha Mukherjee and Sujoy Sinha Roy},
title = {Correlation power analysis of {LESS} and {CROSS}},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/839},
year = {2025},
url = {https://eprint.iacr.org/2025/839}
}
