Re: Proposal for a non-periodic CPRNG (WARNING: CROSSPOST!)

red floyd <>
Sat, 28 Apr 2012 21:09:33 -0700
On 4/28/2012 7:48 PM, sebastian wrote:

I'd like to present a new variation of the standard Shrinking LFSR Generator (SLG) that, with just a few slight modifications, achieves both non-periodicity and a significantly improved level security. An SLG is of course currently considered impervious to cryptoanalysis except for the case where the characteristic polynomial is known (ie: public). So the first modification proposed is to have the polynomial change somehow over time. In this case we'll simply increment the polynomial's binary representation whenever the LFSR's internal state has completed a complete cycle (which will be of course some length on [2, (2^N)-1], where N is the degree of the polynomial). The next modification is to dynamically increase the size of the LFSR whenever an overflow of the polynomial's binary representation is imminent. As an arbitrary convention (and better suggestions are certainly welcome here), the internal state of the LFSR is set to the seed and the binary representation of the

 polynomial is set to seed + 1. That's basically it!

A proof-of-concept implementation of the algorithm written in the C programming language can be found here ( I would sincerely appreciate any comments relating to the algorithm, the source code, or anything else that may be relevant to the discussion here.

May I point out that you're off topic here? You might want to try
sci.crypto or comp.lang.c? C and C++ are separate languages, and
Crypto PRNG algorithms are better addressed by cryptographers, not
developers who may or may not have the necessary background.

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