[Gnuk-users] TRNG output

[Kurt Roeckx]

Hi,

I recently got myself one of those boards acting as TRNG.  I
wanted to verify how good the randomness is, but I'm a little
confused by the documentation and code.

The code talks about 2 ADCs and a total of 4 inputs (Vref, temp,
Vdd, Vdd).  I understand that it's a 12 bit ADC.

I've been looking at them in EP_ROUND_RAW_DATA mode, and I see
some strange results.  I'm not sure I really understand what is
happening, but I get back groups of 32 bytes, which seem to be
16 12 bit values, or each input 4 times sampled.

It seems to be the more times you read it the less noise you get.
Looking at the values I get you're not actually waiting until the
ADC is done converting and the noise is actually caused by timing
differences and not by quantization noise?

Can you explain a little more how it works?


Kurt