[Cryptography] Entropy of a diode

[Ray Dillinger]

On 07/23/2016 06:55 AM, Bill Cox wrote:
> Please stop using reverse-breakdown of emitter-base diodes as noise sources
> for crypto.

"Remember, kids!  The only difference between a diode and a friode
is too much voltage or too many reverse breakdowns!"
                        -- "mr. chips," public TV show circa 1983.

Dang, I liked that show.  It taught electronics hobbyists,
among other things, to actually test their circuits and keep
watch for burned out parts.  So there was the Big Red Trash
Can (with smiley face and happy munching noises) for friodes,
write-only memories, desistors, dark-emitting diodes, and
chips that the magic smoke had leaked out of. He always acted
so happy to find one, because it meant he could fix the darn
problem and go on!

Actually I sort of got the impression he might have been a little
bit toked most of the time, although that might just be the way
he talked naturally.

But yeah, if you're generating noise by reverse breakdowns it
won't take all that long for your diode to turn into a friode.
And friodes just aren't all that chaotic.


				Bear

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