Paper 2024/1350
Update to the Sca25519 Library: Mitigating Tearing-based Side-channel Attacks
Abstract
This short note describes an update to the sca25519 library, an ECC implementation computing the X25519 key-exchange protocol on the Arm Cortex-M4 microcontroller. The sca25519 software came with extensive mitigations against various side-channel and fault attacks and was, to our best knowledge, the first to claim affordable protection against multiple classes of attacks that are motivated by distinct real-world application scenarios. This library is protected against various passive and active side-channel threats. However, both classes of attacks were considered separately, i.e., combining the attacks is considered out-of-scope because to successfully execute such a combined attack, the adversary would need to be very powerful (e.g., a very well-equipped security laboratory). Protection against such powerful adversaries is considered infeasible without using dedicated protected hardware with which Arm Cortex-M4 is not equipped. However, there exists a particular class of easy and cheap active attacks: they are called tearing, and they are well known in the smartcard context. In this paper, we extend the scope of the library to also consider a combination of tearing and side-channel attacks. In this note, we show how we can mitigate such a combination by performing a small code update. The update does not affect the efficiency of the library.
Note: Added Acknowledgements. The results from this note were presented at the OPTIMIST 2024 workshop: https://optimist-workshop.github.io/
Metadata
- Available format(s)
-
PDF
- Category
- Implementation
- Publication info
- Preprint.
- Keywords
- X25519 libraryTearing AttackSide-Channel AnalysisFault Injection
- Contact author(s)
-
lukchmiel @ gmail com
493077 @ mail muni cz - History
- 2024-10-25: revised
- 2024-08-28: received
- See all versions
- Short URL
- https://ia.cr/2024/1350
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2024/1350,
author = {Lukasz Chmielewski and Lubomír Hrbáček},
title = {Update to the Sca25519 Library: Mitigating Tearing-based Side-channel Attacks},
howpublished = {Cryptology {ePrint} Archive, Paper 2024/1350},
year = {2024},
url = {https://eprint.iacr.org/2024/1350}
}