Paper 2025/145

Breaking RSA with Overclocking-induced GPU Faults

Reuven Yakar, Tel Aviv University
Avishai Wool, Tel Aviv University
Eyal Ronen, Tel Aviv University
Abstract

Overclocking is a a supported functionality of Nvidia GPUs, and is a common performance enhancement practice. However, overclocking poses a danger for cryptographic applications. As the temperature in the overclocked GPU increases, spurious computation faults occur. Coupled with well known fault attacks against RSA implementations, one can expect such faults to allow compromising RSA private keys during decryption or signing. We first validate this hypothesis: We evaluate two commercial-grade GPU-based implementations of RSA within openSSL (called RNS and MP), under a wide range of overclocking levels and temperatures, and demonstrate that both implementations are vulnerable. However, and more importantly, we show for the first time that even if the GPU is benignly overclocked to a seemingly ``safe'' rate, a successful attack can still be mounted, over the network, by simply sending requests at an aggressive rate to increase the temperature. Hence, setting any level of overclocking on the GPU is risky. Moreover, we observe a huge difference in the implementations' vulnerability: the rate of RSA breaks for RNS is 4 orders of magnitude higher than that of MP. We attribute this difference to the implementations' memory usage patterns: RNS makes heavy use of the GPU's global memory, which is accessed via both the Unified (L1) cache and the L2 cache; MP primarily uses ``shared'' on-chip memory, which is local to each GPU Streaming MultiProcessor (SM) and is uncached, utilizing the memory banks used for the L1 cache. We believe that the computation faults are caused by reads from the global memory, which under a combination of overclocking, high temperature and high memory contention, occasionally return stale values.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
Preprint.
Keywords
RSAGPUfault attacks
Contact author(s)
reuvenyakar @ gmail com
yash @ eng tau ac il
er @ eyalro net
History
2025-01-31: approved
2025-01-30: received
See all versions
Short URL
https://ia.cr/2025/145
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/145,
      author = {Reuven Yakar and Avishai Wool and Eyal Ronen},
      title = {Breaking {RSA} with Overclocking-induced {GPU} Faults},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/145},
      year = {2025},
      url = {https://eprint.iacr.org/2025/145}
}
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