Paper 2023/294

SCA-LDPC: A Code-Based Framework for Key-Recovery Side-Channel Attacks on Post-Quantum Encryption Schemes

Qian Guo, Lund University
Denis Nabokov, Lund University
Alexander Nilsson, Lund University
Thomas Johansson, Lund University

Whereas theoretical attacks on standardized crypto primitives rarely lead to actual practical attacks, the situation is different for side-channel attacks. Improvements in the performance of side-channel attacks are of utmost importance. In this paper, we propose a framework to be used in key-recovery side-channel attacks on CCA-secure post-quantum encryption schemes. The basic idea is to construct chosen ciphertext queries to a plaintext checking oracle that collects information on a set of secret variables in a single query. Then a large number of such queries is considered, each related to a different set of secret variables, and they are modeled as a low-density parity-check code (LDPC code). Secret variables are finally determined through efficient iterative decoding methods, such as belief propagation, using soft information. The utilization of LDPC codes offers efficient decoding, source compression, and error correction benefits. It has been demonstrated that this approach provides significant improvements compared to previous work by reducing the required number of queries, such as the number of traces in a power attack. The framework is demonstrated and implemented in two different cases. On one hand, we attack implementations of HQC in a timing attack, lowering the number of required traces considerably compared to attacks in previous work. On the other hand, we describe and implement a full attack on a masked implementation of Kyber using power analysis. Using the ChipWhisperer evaluation platform, our real-world attacks recover the long-term secret key of a first-order masked implementation of Kyber-768 with an average of only 12 power traces.

Available format(s)
Attacks and cryptanalysis
Publication info
Lattice-based cryptographycode-based cryptographyside-channel attackslow-density parity-check codes.
Contact author(s)
qian guo @ eit lth se
denis nabokov @ eit lth se
alexander nilsson @ eit lth se
thomas johansson @ eit lth se
2023-02-28: approved
2023-02-27: received
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Creative Commons Attribution


      author = {Qian Guo and Denis Nabokov and Alexander Nilsson and Thomas Johansson},
      title = {SCA-LDPC: A Code-Based Framework for Key-Recovery Side-Channel Attacks on Post-Quantum Encryption Schemes},
      howpublished = {Cryptology ePrint Archive, Paper 2023/294},
      year = {2023},
      note = {\url{}},
      url = {}
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