+     mcsun!sun4nl!alchemy!accucx!nevries
From: (Nico E. de Vries)
Newsgroups: sci.crypt

Subject: Re: IBM-PC flawless true random number generator
Message-ID: <>
Date: 22 Jun 92 15:54:33 GMT
References: <> <>
Organization: Academic Computer Centre Utrecht
Lines: 68

Paul Koning writes:

>In article <>, (Nico E. de Vries)  writes:
>|>some days ago (a week?) I posted an open "ad" for my free random
>|>generator source. I got about 60 requests but if you haven't got it
>|>yet feel free to email me. 

>This looks like the common mistake of assuming that crystal oscillators
>are uncorrelated.  In fact, that's not even close to true.

The generator is less simple than you presume. Its of cource jitter
based but not in a trivial way.

>Then a 3-node network was built, and it locked up in about 10 minutes.
>The cause?  Crystals don't have anything close to a Gaussian distribution;
>instead, the distribution is bimodal with very sharp peaks.  (The reason
>is simple: the manufacturing process involves selection, and crystals
>go into the highest-price bin their measured frequency justifies.  Thus
>the .01% crystals have two sharp peaks: one at +.01%, and one at -.01%
>from the nominal frequency.)

I know this (well not the % etc but the problem of
the randomness distribution of raw measurements not being
usefull at once). The program corrects this problem.

>|>I did several statistical tests on the program and couldn't find any flaws
>|>in it. I hope however others will try at their best to test it as well
>|>and I urge them to post their findings (reply to this posting?). IMHO
>|>the generator is completely undeterministic but one never knows.

>One should know -- and one could know.  In applications like this, you
>need to consider the program "guilty until proven innocent".  In particular,
>running a few tests that don't "find any flaws in it" doesn't tell you

Partially true. There has been a large amount of testing of multiple
people however. I chalenge you to try it. I would be very interested
in the results!

>Coincidentally, I was just a few minutes ago reading an article by E.W.Dijkstra 
>explaining why it is absurd to think of computer science as an experimental
>science.  Here we have a case in point...

My source has to do with hardware, not with software (althought the software
is needed to translate the hardware info in a usefull form). 

>	paul koning

>|>"Unfortunately, the current generation of mail programs do not have checkers
>|> to see if the sender knows what he is talking about" (A.S. Tanenbaum)
>(Unfortunately, the same thing is true for word processors, judging by
>some recent books...)

And what about newspapers, magazines and television shows :-)

Nico E. de Vries
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"Unfortunately, the current generation of mail programs do not have checkers
 to see if the sender knows what he is talking about" (A.S. Tanenbaum)