Hugo Mills <hugo@???> wrote:
> The VIA one claims to use "frequency variations
> in a group of unlocked oscillators". I know
> almost nothing about electronics, so I won't
> claim to understand what that means in practice.
> :)
I've just found analyses of the Via and Intel
RNGs:
http://www.cryptography.com/research/evaluations.html
There's a block diagram on page 8 of the Via
paper. It's quite a complex circuit, with three
open-loop VCOs at 450-810MHz, and one more at
20-68MHz. Two of the high-frequency and the one low
frequency VCOs are used to provide an unstable
clock to a flip-flop, which samples the output
from the remaining high-frequency VCO.
The paper concludes that it generates high-quality
entropy.
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem.
