[onerng talk] RNG designs

[Paul Campbell]

On Fri, 31 Jan 2014 20:16:50 iang wrote:
>
> 3. In contrast, I think a little whitening on the Collector is probably an 
> inevitable thing, as people tend to equate statistical artifacts with lack 
> of quality.

yeah, I kind of figured that, I have to keep reminding myself I'm not trying to 
make an RNG but an entropy source

> 4.  A far more important thing for serious entropy engineers is the lower 
> bound on entropy that is delivered.  Generally couched in terms of bits per 
> byte.  Having that number estimated (c.f., Denker's process) is very 
> valuable.

yeah, I know I'm sampling a signal way above it's actual frequency (at least 
10 times the rate I'm sampling from looking on the scope), so what's coming 
out has a lot to do with the voltage level I'm sampling at (from analog to 
digital) I've spent a while poking at levels to get as close as possible to 
50:50 1s/0s - to my probably naive point of view at a first approximation we 
can calculate the entropy from the   amount we're off from 50:50 - 5% more 1s 
means something like 90% entropy per byte - ~7 bits or entropy per byte

> 1.  Ideally, I would treat the device as two separate Collectors and read it
> the diode part separately from the RF stream.
> 
> 2.  But from an engineering perspective I'd just be annoyed at having to
> twice the amount of work, twice the threads, twice the potential for
> trouble.  I'd probably just end up reading the interleaved stream and
> having one Collector.

actually it's pretty easy (I actually took that bit out, the thing this came 
from had 3 streams)

what I can't do is create streams on the fly, USB sort of forces me to create a 
static number at boot time

> 3. On the supply side however, you're likely to be criticized strongly for
> only offering the one direction.  So having the interleaves (3) and the
> separate feeds (1,2) is the way to go.

I'm not quite sure what you mean by "one direction" - (one feed?)

	Paul