Here's another iteration: A user supplied board with a high-gain op-amp, a comparator, and a latch -- accepting a clock line -- could produce a definite noise-i

Here's another iteration: A user supplied board with a high-gain op-amp, a comparator, and a latch -- accepting a clock line -- could produce a definite noise-informed bit sequence. This bit sequence could be observed both at that level and the software level, to confirm that no alteration had taken place in-between, in the motherboard/chipset etc.