Re: Simple Hardware RNG Idea

[tcmay@got.net (Timothy C. May)]

At 4:14 PM 9/28/95, cjs wrote:
>Hello all.
>
>Someone mentioned this on IRC last night, and it sounded like a really
>cool idea, so I thought I'd mention it.
>
>The idea is to generate random numbers using a geiger counter tube and
>a small portion of radioactive substance (like perhaps the stuff they
>use in smoke detectors?) Would that be random enough?
>
>I thought it was a neat idea anyway.


It's a well-known idea. My FAQ has a section on this, and the Cypherpunks
archives have many mentions of this.

For the newcomers, here are some of the issues, very briefly presented:

1. Incorporating a "Geiger counter tube" is nontrivial. A solid-state
detector does the same thing, and is a better approach.

2. Incorporating Am-241 or other alpha emitters in microcurie levels would
require licensing, regulatory oversight, etc., etc. Don't count on it.

3. Data rates are fairly low. Anything that "clicks" at high rates (> 1K
counts per second) would be too radioactive to ship.

4. Zener diodes and other random noise sources are cheaper to build, more
consistent in output, and easier to integrate into actual products.

--Tim May

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Timothy C. May              | Crypto Anarchy: encryption, digital money,
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