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Cryptanalysis of Achterbahn

  • Thomas Johansson
  • Willi Meier
  • Frédéric Muller
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4047)

Abstract

We present several attacks against the Achterbahn stream cipher, which was proposed to the eSTREAM competition. We can break the reduced and the full version with complexity of 255 and 261 steps.

Extensions of our attacks are also described to break modified versions of the Achterbahn stream cipher, which were proposed following the publication of preliminary cryptanalysis results.

These attacks highlight some problems in the design principle of Achterbahn, i.e., combining the outputs of several nonlinear (but small) shift registers using a nonlinear (but rather sparse) output function.

Keywords

Output Function Linear Complexity Parity Check Stream Cipher Output Sequence 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Thomas Johansson
    • 1
  • Willi Meier
    • 2
  • Frédéric Muller
    • 3
  1. 1.Department of Information TechnologyLund UniversityLundSweden
  2. 2.FH AargauWindischSwitzerland
  3. 3.HSBCFrance

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