X-FCSR – A New Software Oriented Stream Cipher Based Upon FCSRs

  • François Arnault
  • Thierry P. Berger
  • Cédric Lauradoux
  • Marine Minier
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4859)


Feedback with Carry Shift Registers (FCSRs) are a promising alternative to LFSRs in the design of stream ciphers. The previous constructions based on FCSRs were dedicated to hardware applications [3]. In this paper, we will describe X-FCSR a family of software oriented stream ciphers using FCSRs. The core of the system is composed of two 256-bits FCSRs. We propose two versions: X-FCSR-128 and X-FCSR-256 which output respectively 128 and 256 bits at each iteration. We study the resistance of our design against several cryptanalyses. These stream ciphers achieve a high throughput and are suitable for software applications (6.3 cycles/byte).


stream cipher FCSRs software design cryptanalysis 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • François Arnault
    • 1
  • Thierry P. Berger
    • 1
  • Cédric Lauradoux
    • 2
  • Marine Minier
    • 3
  1. 1.XLIM (UMR CNRS 6172), Université de Limoges, 123 avenue Albert Thomas, F-87060 Limoges CedexFrance
  2. 2.INRIA - projet CODES, B.P. 105, 78153 Le Chesnay CedexFrance
  3. 3.INSA de Lyon - Laboratoire CITI, 21 Avenue Jean Capelle, 69621 Villeurbanne CedexFrance

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