RNG designs

[Ian Grigg]

1.  The permanent copy of my guide or howto on RNGs is now at:

http://iang.org/ssl/hard_truths_hard_random_numbers.html

And it is receiving some tightening up hints from readers.  Nothing dramatic as yet tho.

2.  This is primarily a guide for software people.  Although the design ideas might be applied to hardware, happily, they don't really fit there.  The philosophical claw is that one always suffers under the software engineer's distrust of hardware, which breaks or is otherwise subject to physical departures from spec.  Given that, the ideal hardware for the software engineer is another "Collector" to use that taxonomy.  In the software we'll do the mixing and whitening and expanding, we have to do that anyway, so we're unconcerned about those features on the Collector.

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.

4.  Afar 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.

Just some quick comments!  Looking forward to seeing that device...