On 1/6/2012 9:48 AM, Paul Fuller wrote:

> I saw an early hardware RNG device that relied on thermal noise. It was
> about the size of a microwave oven. Most of it was I think to ensure
> that the noise source was kept in a very narrow temperature range so
> that physical randomness was never biased. One of these was hooked up to
> the Internet and you could get the random stream. Sort of defeats many
> of the possible uses of randomness when everybody can see the same
> stream. But for simulations and testing algorithms it was useful I guess.

When I was a cryptographic maintenance technician in the USAF, I did 
work on one piece of gear which actually generated random bits, using 
the thermal noise from a component chosen for this task.  The voltage 
bias on the components had to be within precise limits.  I forget 
exactly what the random bits were used for.  I recall that we were told 
in no uncertain terms not to fiddle with any of the circuitry involved; 
if it didn't work, we simply pulled the circuit card and sent it back to 
the depot.  For the rest of the equipment, we troubleshot down to the 
component level.  The equipment was phased out around 1990.

Regards,
John

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