Breaking the F-FCSR-H Stream Cipher in Real Time

  • Martin Hell
  • Thomas Johansson
Conference paper

DOI: 10.1007/978-3-540-89255-7_34

Part of the Lecture Notes in Computer Science book series (LNCS, volume 5350)
Cite this paper as:
Hell M., Johansson T. (2008) Breaking the F-FCSR-H Stream Cipher in Real Time. In: Pieprzyk J. (eds) Advances in Cryptology - ASIACRYPT 2008. ASIACRYPT 2008. Lecture Notes in Computer Science, vol 5350. Springer, Berlin, Heidelberg


The F-FCSR stream cipher family has been presented a few years ago. Apart from some flaws in the initial propositions, corrected in a later stage, there are no known weaknesses of the core of these algorithms. The hardware oriented version, called FCSR-H, is one of the ciphers selected for the eSTREAM portfolio.

In this paper we present a new and severe cryptanalytic attack on the F-FCSR stream cipher family. We give the details of the attack when applied on F-FCSR-H. The attack requires a few Mbytes of received sequence and the complexity is low enough to allow the attack to be performed on a single PC within seconds.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  • Martin Hell
    • 1
  • Thomas Johansson
    • 1
  1. 1.Dept. of Electrical and Information TechnologyLund UniversityLundSweden

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