From: Dave Dittrich <dittrich@cac.washington.edu>
Date: Mon, 2 Oct 95 11:17:56 PDT
To: cypherpunks@toad.com
Subject: Re: Simple Hardware RNG Idea
Message-ID: <9510021817.AA01271@red2.cac.washington.edu>
MIME-Version: 1.0
Content-Type: text/plain



> Perry writes, regarding alpha decay counts for random numbers:
> 
> > And, as I noted, there are RS232 interfaceable radiation detectors you
> > can buy off the shelf -- no hardware hacking needed.
> 
> As far as a radiation source goes, the Americium 241 source from a cheap
> smoke detector is just dandy. A while ago, I took one into the lab and
> put it on a scintillating counter and got alpha hits at roughly
> half-microsecond intervals. It was a while ago, so I forget how this compared
> to the rating in Curies on the package. But that would be fine for a
> low-to-moderate bandwidth RNG.

I was thinking about this the other day and wondered if it wouldn't be
cheap and relatively easy to build a board that samples and sums
several randomly selected signals on various frequencies on the AM
broadcast spectrum.  This should catch stations in nearly all
metropolitan (and most rural areas as well) and would require that
someone be able to broadcast at multiple frequencies to "cheat" it.

Perhaps this would be affected by RF interference from the motherboard
itself.  If so, could the RF radiation from the motherboard itself be
used to generate random numbers?

-- 
Dave Dittrich                  Client Services, Computing & Communications
dittrich@cac.washington.edu    University of Washington

<a href="http://www.washington.edu/People/dad/">
Dave Dittrich / dittrich@cac.washington.edu</a>