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A New Distinguisher for Clock Controlled Stream Ciphers

  • Håkan Englund
  • Thomas Johansson
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3557)

Abstract

In this paper we present a distinguisher targeting towards irregularly clocked filter generators. The attack is applied on the irregularly clocked stream cipher called LILI-II. LILI-II is the successor of the cipher LILI-128 and its design was published in [1]. There have been no known attacks better than exhaustive key search on LILI-II. Our attack is the first of this kind that distinguishes the cipher output from a random source using 2103 bits of keystream using computational complexity of approximately 2103 operations.

Keywords

Boolean Function Correlation Property Stream Cipher Linear Feedback Shift Register Random Source 
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 2005

Authors and Affiliations

  • Håkan Englund
    • 1
  • Thomas Johansson
    • 1
  1. 1.Dept. of Information TechnologyLund UniversityLundSweden

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