Cryptology ePrint Archive: Report 2014/951

Modified Alternating Step Generators with Non-Linear Scrambler

Robert Wicik and Tomasz Rachwalik and Rafał Gliwa

Abstract: Pseudorandom generators, which produce keystreams for stream ciphers by the exclusive-or sum of output bits from alternately clocked linear feedback shift registers, are vulnerable to cryptanalysis. In order to increase their resistance to attacks, we introduce a nonlinear scrambler at the output of these generators. The role of the scrambler plays the nonlinear feedback shift register. In addition, we propose the Modified Alternating Step Generator (MASG1S) built with the nonlinear scrambler and regularly or irregularly clocked linear feedback shift registers with nonlinear filtering functions.

Category / Keywords: secret-key cryptography / stream ciphers, alternating step generators, linear/nonlinear feedback shift registers

Original Publication (with minor differences): Annales UMCS Informatica AI XIV, 1 (2014) 61-74

Date: received 20 Nov 2014

Contact author: r wicik at wil waw pl

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Note: Continuation of the work described in the publication:

Version: 20141120:161230 (All versions of this report)

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