building a true RNG (was: Quantum Computing ...)

[jamesd at echeque.com]

    --
On 22 Jul 2002 at 15:39, David Honig wrote:
> You should be able to use any source which you know is not a   
> PRNG as the entropy-source in a true RNG.  You should be able to 
> use entropy (and stat tests) to measure the source entropy after 
> digitization.

You cannot measure entropy retrospectively.  You need to have a   
theory as to where the entropy is coming from, in order to   
reliably measure it.

Thus hardware sources should be based on simple and well   
understood physical principles, such as Johnson noise or shot   
noise. 

Entropy is not quite a physical quantity -- rather it is on the  
slippery edge between being a physical thing and a philosophical  
thing. If you are not careful, you will slip into a deep epistemic 
bog and find yourself needing to ask "how do we know what is 
knowable, and what is the whichness of why?"

To avoid such deep waters, know where your entropy is coming from. 

    --digsig
         James A. Donald
     6YeGpsZR+nOTh/cGwvITnSR3TdzclVpR0+pr3YYQdkG
     SMGOwg3qIP0/FsfmA7GzZGN/XYAabuqcE9Z9eiuB
     2CBUwRUngy0VcmaR93NvqduyZBKgppbTUy49tSdEn


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