Cryptology ePrint Archive: Report 2006/010

Finding Characteristic Polynomials with Jump Indices

Steve Babbage and Matthew Dodd

Abstract: Jansen introduced a technique for building LFSRs that can be clocked a large number of times with a single simple operation. These may be useful in the construction of stream ciphers based on clock-controlled LFSRs. However, for LFSR sizes of typical interest, it appears generally hard to find such jumping LFSRs with particular desired parameters. In this note we explain a trick which we used to find the jumping LFSRs in MICKEY and MICKEY-128, and which may be useful for future applications.

Category / Keywords: MICKEY, stream cipher, ECRYPT, irregular clocking

Date: received 9 Jan 2006, last revised 13 Jan 2006

Contact author: steve babbage at vodafone com

Available format(s): PDF | BibTeX Citation

Note: More complete references, plus one typo correction

Version: 20060113:103627 (All versions of this report)

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