Quantum RNG

John Denker jsd at av8n.com
Tue Jul 4 12:59:35 EDT 2006


Andrea Pasquinucci wrote:
> 
> http://www.idquantique.com/products/quantis.htm
> 
> "Quantis is a physical random number generator exploiting an elementary 
> quantum optics process. Photons - light particles - are sent one by one 
> onto a semi-transparent mirror and detected. The exclusive events 
> (reflection - transmission) are associated to "0" - "1" bit values."
> 
> Just curious of your opinion.


This is discussed at
  http://www.av8n.com/turbid/paper/turbid.htm#sec-hrng-attack

Quantum processes are in some very narrow theoretical sense more
"fundamentally" random than other sources of randomness, such as
thermal noise ... but they are not better in any practical sense.

The basic quantum process is less sensitive to temperature than a purely
thermal process ... but temperature dependence is easily accounted for
in any practical situation, and -- more importantly -- there are all
sorts of other practical considerations (such as detector dead-time
issues) that make real quantum detectors far from ideal.

The devil is in the details, and obtaining the raw data from a quantum
process is nowhere near necessary and nowhere near sufficient to make
a good randomness generator.

I have no idea whether the quantis generator got the devilish details right
... but in any case, there are easier ways to make a generator that is just
as good, or better.

For details, see
  http://www.av8n.com/turbid/paper/turbid.htm


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