On the Resynchronization Attack

  • Jovan Dj. Golić
  • Guglielmo Morgari
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2887)


The resynchronization attack on stream ciphers with a linear next-state function and a nonlinear output function is further investigated. The number of initialization vectors required for the secret key reconstruction when the output function is known is studied in more detail and a connection with the so-called 0-order linear structures of the output function is established. A more difficult problem when the output function is unknown is also considered. An efficient branching algorithm for reconstructing this function along with the secret key is proposed and analyzed. The number of initialization vectors required is larger in this case than when the output function is known, and the larger the number, the lower the complexity.


Stream ciphers Boolean functions Resynchronization Reconstruction algorithms 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • Jovan Dj. Golić
    • 1
  • Guglielmo Morgari
    • 2
  1. 1.System on ChipTelecom Italia LabTurinItaly
  2. 2.Telsy Elettronica e TelecomunicazioniTurinItaly

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