[Cryptography] Entropy of a diode

[Marcus D. Leech]

On 07/21/2016 06:36 AM, Bill Cox wrote:
> I have not seen any papers on this, but I can tell you that if you buy 
> a regular zener diode, it will generate a disappointingly low amount 
> of noise, many times less than the reverse breakdown Vbe of a cheap 
> transistor.  Apparently, zener avalanche noise is highly dependent on 
> the process used, and if you tune the process to lessen avalanche 
> noise, you can eliminate most it.
>
> Bill
Something useful to note is that the noise goes up considerably for 
higher-voltage Zeners, which is why almost all commercial noise sources
   for RF use Zeners rated at about 20V, and run them at 28V.

I use ordinary Zeners all the time (12V and higher) as RF noise 
sources.  They work well.


>
> On Wed, Jul 20, 2016 at 2:17 PM, Kurt Roeckx <kurt at roeckx.be 
> <mailto:kurt at roeckx.be>> wrote:
>
>     Hi,
>
>     I'm trying to understand the entropy generated by a reversed diode
>     in avalanche breakdown mode.  Does anybody know of a paper that
>     describes it, maybe talk about the distribution of the noise, the
>     effect of temperature changes, RF interference?
>
>     I'm trying to analyze the chaoskey.
>
>
>     Kurt
>
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