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OT-PCA: New Key-Recovery Plaintext-Checking Oracle Based Side-Channel Attacks on HQC with Offline Templates

Dong, Haiyue LU and Guo, Qian LU (2025) In IACR Transactions on Cryptographic Hardware and Embedded Systems (TCHES) 2025(1).
Abstract
In this paper, we introduce OT-PCA, a novel approach for conducting Plaintext-Checking (PC) oracle based side-channel attacks, specifically designed for Hamming Quasi-Cyclic (HQC). By calling the publicly accessible HQC decoder, we build offline templates that enable efficient extraction of soft information for hundreds of secret positions with just a single PC oracle call. Our method addresses critical challenges in optimizing key-related information extraction, including maximizing decryption output entropy and ensuring error pattern independence, through the use of genetic-style algorithms.
Extensive simulations demonstrate that our new attack method significantly reduces the required number of oracle calls, achieving a 2.4-fold... (More)
In this paper, we introduce OT-PCA, a novel approach for conducting Plaintext-Checking (PC) oracle based side-channel attacks, specifically designed for Hamming Quasi-Cyclic (HQC). By calling the publicly accessible HQC decoder, we build offline templates that enable efficient extraction of soft information for hundreds of secret positions with just a single PC oracle call. Our method addresses critical challenges in optimizing key-related information extraction, including maximizing decryption output entropy and ensuring error pattern independence, through the use of genetic-style algorithms.
Extensive simulations demonstrate that our new attack method significantly reduces the required number of oracle calls, achieving a 2.4-fold decrease for hqc-128 and even greater reductions for hqc-192 and hqc-256 compared to current state-of-the-art methods. Notably, the attack shows strong resilience against inaccuracy in the PC oracle—when the oracle accuracy decreases to 95%, the reduction factor in oracle call requirements increases to 7.6 for hqc-128.
Lastly, a real-world evaluation conducted using power analysis on a platform with an ARM Cortex-M4 microcontroller validates the practical applicability and effectiveness of our approach. (Less)
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author
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organization
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type
Contribution to journal
publication status
published
subject
in
IACR Transactions on Cryptographic Hardware and Embedded Systems (TCHES)
volume
2025
issue
1
publisher
Ruhr-University of Bochum
external identifiers
  • scopus:85215442866
ISSN
2569-2925
DOI
10.46586/tches.v2025.i1.251-274
language
English
LU publication?
yes
id
b5fe5a05-b34b-40d6-af98-0ef9895d8769
date added to LUP
2025-02-19 06:39:20
date last changed
2025-05-29 12:09:24
@article{b5fe5a05-b34b-40d6-af98-0ef9895d8769,
  abstract     = {{In this paper, we introduce OT-PCA, a novel approach for conducting Plaintext-Checking (PC) oracle based side-channel attacks, specifically designed for Hamming Quasi-Cyclic (HQC). By calling the publicly accessible HQC decoder, we build offline templates that enable efficient extraction of soft information for hundreds of secret positions with just a single PC oracle call. Our method addresses critical challenges in optimizing key-related information extraction, including maximizing decryption output entropy and ensuring error pattern independence, through the use of genetic-style algorithms.<br/>Extensive simulations demonstrate that our new attack method significantly reduces the required number of oracle calls, achieving a 2.4-fold decrease for hqc-128 and even greater reductions for hqc-192 and hqc-256 compared to current state-of-the-art methods. Notably, the attack shows strong resilience against inaccuracy in the PC oracle—when the oracle accuracy decreases to 95%, the reduction factor in oracle call requirements increases to 7.6 for hqc-128.<br/>Lastly, a real-world evaluation conducted using power analysis on a platform with an ARM Cortex-M4 microcontroller validates the practical applicability and effectiveness of our approach.}},
  author       = {{Dong, Haiyue and Guo, Qian}},
  issn         = {{2569-2925}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Ruhr-University of Bochum}},
  series       = {{IACR Transactions on Cryptographic Hardware and Embedded Systems (TCHES)}},
  title        = {{OT-PCA: New Key-Recovery Plaintext-Checking Oracle Based Side-Channel Attacks on HQC with Offline Templates}},
  url          = {{http://dx.doi.org/10.46586/tches.v2025.i1.251-274}},
  doi          = {{10.46586/tches.v2025.i1.251-274}},
  volume       = {{2025}},
  year         = {{2025}},
}