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Correlated Keystreams in Moustique

  • Emilia Käsper
  • Vincent Rijmen
  • Tor E. Bjørstad
  • Christian Rechberger
  • Matt Robshaw
  • Gautham Sekar
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5023)

Abstract

Moustique is one of the sixteen finalists in the eSTREAM stream cipher project. Unlike the other finalists it is a self-synchronising cipher and therefore offers very different functional properties, compared to the other candidates. We present simple related-key phenomena in Moustique that lead to the generation of strongly correlated keystreams and to powerful key-recovery attacks. Our best key-recovery attack requires only 238 steps in the related-key scenario. Since the relevance of related-key properties is sometimes called into question, we also show how the described effects can help speed up exhaustive search (without related keys), thereby reducing the effective key length of Moustique from 96 bits to 90 bits.

Keywords

eSTREAM Moustique related keys 

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References

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    Bernstein, D.J.: Related-key attacks: who cares? eSTREAM discussion forum (June 22, 2005), http://www.ecrypt.eu.org/stream/phorum/
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    Daemen, J., Kitsos, P.: The Self-Synchronising Stream Cipher Moustique, http://www.ecrypt.eu.org/stream/mosquitop3.html
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Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  • Emilia Käsper
    • 1
  • Vincent Rijmen
    • 1
    • 3
  • Tor E. Bjørstad
    • 2
  • Christian Rechberger
    • 3
  • Matt Robshaw
    • 4
  • Gautham Sekar
    • 1
  1. 1.K.U.Leuven, ESAT-COSIC 
  2. 2.The Selmer CenterUniversity of Bergen 
  3. 3.Graz University of Technology 
  4. 4.France Télécom Research and Development 

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