Rafal Gliwa

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– Pseudorandom generators, which produce keystreams for stream ciphers by the exclusive-or sum of outputs of alternately clocked linear feedback shift registers, are vulnerable to cryptanalysis. In order to increase their resistance to attacks, we introduce a non-linear scrambler at the output of these generators. Non-linear feedback shift register plays(More)
Alternate clocking of linear feedback shift registers is the popular technique used to increase the linear complexity of binary sequences produced by keystream generators designed for stream ciphers. The analysis of the best known attacks on the alternating step generator led us to add nonlinear filtering functions and the nonlinear scrambler to the(More)
The first part of the paper explains the need for combining message encryption and authen-tication. We begin with the example to emphasize the fact that privacy ‡ does not imply authenticity. Then we prove, one needs both privacy and authenticity, even if one's aim is just getting privacy. In the second part we present an overview of different methods for(More)
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