[Cryptech Tech] Avalanche noise test boards

[Peter Gutmann]

Benedikt Stockebrand <bs at stepladder-it.com> writes:

>Actually, even that isn't "perfect": As the radiation source decays, the
>thing "slows down", at least in theory.  This could in theory even "break"
>the von Neumann extractor.

Depends on your source.  I wasn't planning on using an active source, just
background radiation.  OTOH if you do want an active source, buy a lump of
pitchblende on eBay, that'll be radioactive as good as forever.

>But that said, I've got no intention to touch anything doing with
>radioactivity.

It's not a terribly practical source, just mentioning it as the canonical
example of an unpredictable process.  In any case if you want a safe source of
radioactivity get a few bananas, only problem is that the half-life of a
banana (a week or so) is a lot less than the half-life of the potassium-40 in
it (about a billion years).

(Also, don't go into a supermarket and run a geiger counter over their
bananas, they seem to get a bit upset about that :-).

Peter.