[Cryptech Tech] Noise board on Novena

[Fredrik Thulin]

On Thursday, September 18, 2014 10:34:28 AM Bill Cox wrote:
> Awesome!  Would you guys welcome yet another TRNG board for this
> platform?  I've ordered some parts and was going to prototype my
> board-level infinite-noise-multiplier.

Personally I _very much_ welcome experimentation with other sources.

In my mind, the HSM we build will support third party entropy sources through 
a simple SPI interface.

I don't think there is disagreement around this but for some people it is a 
more distant goal - in the short term the only agreement we have is for one 
external source that is avalanche noise connected directly to the FPGA.

Would the SPI model work for what you had in mind, or would that fall on the 
"I can't trust the security of what's on the other end" aspect if you had to 
put an MCU in there to talk SPI?

Can you tell more about how you would whiten the high-speed, low-quality 
entropy from the A/D?

We haven't gotten to sort of specifying what quality the FPGA will 
expect/require from the external entropy source(s). I'd say it probably won't 
be "must be perfectly random", but I don't know how we will define it.

As food for thought, maybe the spec would be something like "must give a Monte 
Carlo test value of less than 0.1% in 100k readings" (I totally just made up 
those numbers).

...
> If such a board would be welcome, is there a place I can read about
> developing boards for the Novena?

I think the availability of Novenas is quite limited still. Maybe you can 
start out with a DE0? Joachim has all the cores running on that board. 

I like how you've made a simulation of your circuit in a Python program! =)

/Fredrik