Improved Timing Attacks against the Secret Permutation in the McEliece PKC


  • Dominic Bucerzan Aurel Vlaicu University of Arad Department of Mathematics and Computer Science Romania, 310330 Arad, Elena Dragoi, 2 Corresponding
  • Pierre-Louis Cayrel Laboratoire Hubert Curien, UMR CNRS 5516, Université de Lyon, Saint-Etienne, France
  • Vlad Dragoi Laboratoire LITIS - EA 4108 Université de Rouen - UFR Sciences et Techniques, 76800 Saint Etienne du Rouvray, France
  • Tania Richmond Laboratoire IMATH, EA 2134, Avenue de l’Université , BP 20132, 83957 La Garde Cedex, France


communication systems, theory of error correcting codes, code-based cryptography, McEliece PKC, side-channel attacks, timing attack, extended Euclidean algorithm


In this paper, we detail two side-channel attacks against the McEliece public-key cryptosystem. They are exploiting timing differences on the Patterson decoding algorithm in order to reveal one part of the secret key: the support permutation. The first one is improving two existing timing attacks and uses the correlation between two different steps of the decoding algorithm. This improvement can be deployed on all error-vectors with Hamming weight smaller than a quarter of the minimum distance of the code. The second attack targets the evaluation of the error locator polynomial and succeeds on several different decoding algorithms. We also give an appropriate countermeasure.


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