<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Jul 20, 2016 at 2:17 PM, Kurt Roeckx <span dir="ltr"><<a href="mailto:kurt@roeckx.be" target="_blank">kurt@roeckx.be</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
I'm trying to understand the entropy generated by a reversed diode<br>
in avalanche breakdown mode. <br></blockquote><div><br></div><div> As others noted the noise depends on the silicon process and</div><div>low noise processes are the goal of most foundries.   Thus</div><div>cheep or out of specification parts may work "better" or "worse"</div><div>depending on the circuit being used.   <br><br>Adjusting the reverse bias to find the knee seems to </div><div>be important and a source of bias for a zener source.<br><br>Chaoskey uses a pair of back to back <br><br><br>Google search found a couple things.  </div><div>Looking at the reverse space of noise reduction might prove more educational.</div><div><br><a href="http://kundoku.free.fr/N/012/Noise%20In%20Receiving%20Systems/Noise%20In%20Receiving%20Systems.pdf">http://kundoku.free.fr/N/012/Noise%20In%20Receiving%20Systems/Noise%20In%20Receiving%20Systems.pdf</a><br><a href="http://firasaboulatif.free.fr/index_files/gaidaa%20book/Generate%20%20gaussion%20noise%20by%20zener%20diode/Random%20Electrical%20Noise.pdf">http://firasaboulatif.free.fr/index_files/gaidaa%20book/Generate%20%20gaussion%20noise%20by%20zener%20diode/Random%20Electrical%20Noise.pdf</a></div><div><br>Follow the prior art in patents...<br><a href="https://www.google.com/patents/US4853884">https://www.google.com/patents/US4853884</a><br><br>Analysis tool for a Hardware Random Number Generator<br><a href="https://github.com/BartMassey/anrand">https://github.com/BartMassey/anrand</a><br><br><a href="http://altusmetrum.org/ChaosKey/">http://altusmetrum.org/ChaosKey/</a><br><br><a href="https://www.phoronix.com/scan.php?page=news_item&px=ChaosKey-1.0-2016">https://www.phoronix.com/scan.php?page=news_item&px=ChaosKey-1.0-2016</a><br><br><a href="https://www.eeweb.com/blog/extreme_circuits/simple-white-noise-generator">https://www.eeweb.com/blog/extreme_circuits/simple-white-noise-generator</a><br><br></div><div><br></div><div>Two references here.</div><div><a href="https://www.schneier.com/blog/archives/2016/04/friday_squid_bl_523.html">https://www.schneier.com/blog/archives/2016/04/friday_squid_bl_523.html</a><br><br>Tinkering:</div><div><a href="http://holdenc.altervista.org/avalanche/">http://holdenc.altervista.org/avalanche/</a><br><a href="http://imotp.sourceforge.net/noise.pdf">http://imotp.sourceforge.net/noise.pdf</a></div><div><a href="http://imotp.sourceforge.net/noise.pdf">http://imotp.sourceforge.net/noise.pdf</a>    <--- interesting.</div><div>   From the above link : "Transistor junction noise provides a source of true random data that can </div><div>   be sampled and
stored on a computer. However, this sampled data does not contain 1 bit of entropy </div><div>   per bit
of stored data. It is therefore necessary to post process the data samples to distil the
existing </div><div>   entropy into a smaller number of high entropy bits."</div> <br><div><br><br></div></div><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">  T o m    M i t c h e l l</div></div>
</div></div>