Cryptology ePrint Archive: Report 2000/040

Decimation Attack of Stream Ciphers

Eric FILIOL

Abstract: This paper presents a new attack called {\em Decimation Attack} of most stream ciphers. It exploits the property that multiple clocking (or equivalently $d$-th decimation) of a LFSR can simulate the behavior of many other LFSRs of possible shorter length. It yields then significqnt improvements of all the previous known correlation and fast correlation attacks provided a new criterion is satisfied. This criterion on the length of the feedback polynomial is then defined to resist the decimation attack. Simulation results and complexity comparison are detailed for ciphertext only attack.

Category / Keywords: secret-key cryptography / stream cipher linear feedback shift register,correlation attack, fast correlations attack,sequence decimation, multiple clocking

Publication Info: Corrected and revised version

Date: received 5 Aug 2000, revised 10 Aug 2000, revised 23 Aug 2000, revised 22 Sep 2000

Contact author: efiliol at mailhost esm-stcyr terre defense gouv fr

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | BibTeX Citation

Version: 20000922:082929 (All versions of this report)

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