Paper 2022/106

Profiling Side-Channel Attacks on Dilithium: A Small Bit-Fiddling Leak Breaks It All

Soundes Marzougui, Vincent Ulitzsch, Mehdi Tibouchi, and Jean-Pierre Seifert


We present an end-to-end (equivalent) key recovery attack on the Dilithium lattice-based signature scheme, one of the top contenders in the NIST postquantum cryptography competition. The attack is based on a small side-channel leakage we identified in a bit unpacking procedure inside Dilithium signature generation. We then combine machine-learning based profiling with various algorithmic techniques, including least squares regression and integer linear programming, in order to leverage this small leakage into essentially full key recovery: we manage to recover, from a moderate number of side-channel traces, enough information to sign arbitrary messages. We confirm the practicality of our technique using concrete experiments against the ARM Cortext-M4 implementation of Dilithium, and verify that our attack is robust to real-world conditions such as noisy power measurements. This attack appears difficult to protect against reliably without strong side-channel countermeasures such as masking of the entire signing algorithm, and underscores the necessity of implementing such countermeasures despite their known high cost.

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Cryptographic protocols
Publication info
Preprint. Minor revision.
Contact author(s)
marzougui soundes @ gmail com
2022-02-09: last of 3 revisions
2022-01-31: received
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      author = {Soundes Marzougui and Vincent Ulitzsch and Mehdi Tibouchi and Jean-Pierre Seifert},
      title = {Profiling Side-Channel Attacks on Dilithium: A Small Bit-Fiddling Leak Breaks It All},
      howpublished = {Cryptology ePrint Archive, Paper 2022/106},
      year = {2022},
      note = {\url{}},
      url = {}
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