Forwarded message:

From: "Nobuki Nakatuji" <bd1011@hotmail.com> Subject: Re: Gao's Chaos Cryptosystem Algorithm Date: Mon, 08 Sep 1997 23:18:33 PDT

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Nobuki Nakatuji wrote:

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I will just repeat Prof. Choate's question, how do you generate Ch.

I think Igor got a bruised ego...

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Ch generate

begin Xn+1=aXn(1.0-Xn) return Xn+1 end

What does aXn(1.0-Xn) mean? That's what I do not understand.

More explicity it is a weird IFS nomenclature (I believe). What is being said here near as I can tell is: Take some function X and takes it's output for the n'th result and use it as the input for calculating n+1. We take the n'th value and subtract it from 1, assuming the RNG function returns 0 <= x <= 1, and feed this into X take the result and multiply by some scalar, a, producing Xn+1. Not shure exactly why the subtraction from unity is in there. All it really does is give you a number > .5 if you are less than .5 and visa versa. Doesn't enhance the IFS in any meaningful way that I can see. The scalar multiplier, a, isn't doing anything but scaling the output. Again it isn't effecting the IFS in a meaningful way that I can tell. It would be more interesting to know the specific X's since this is what will determine the 'level' of chaos that results since this is what will define the strange attractor. Section 1.3 onward of the reference I mentioned previously goes into some detail on the various feedback processes and how to describe them somewhat formaly. It's called a 'One Step Feedback Machine'. ____________________________________________________________________ | | | The financial policy of the welfare state requires that there | | be no way for the owners of wealth to protect themselves. | | | | -Alan Greenspan- | | | | _____ The Armadillo Group | | ,::////;::-. Austin, Tx. USA | | /:'///// ``::>/|/ http:// www.ssz.com/ | | .', |||| `/( e\ | | -====~~mm-'`-```-mm --'- Jim Choate | | ravage@ssz.com | | 512-451-7087 | |____________________________________________________________________|