Martijn van Steenbergen
roger peppe wrote:
if you're prepared to expend a few cpu cycles, you can always use something like the following "beating clocks" algorithm, which should generate at least some genuine randomness, as long as you've got preemptive scheduling, and a few hardware interrupts around the place.
I was taught that using the scheduler to generate randomness is a pretty bad idea, because randomness is actually a *very* strong property to demand from a stream of bits, and a scheduler doesn't offer any such guarantees.
The scheduler is as fine a chaotic system as your average cube centimetre of air: Very, very little disturbances (like a keypress or a network packet) can change the order of task switching drastically, even more so if stuff runs with different priorities. What it certainly (hopefully) won't guarantee is a random distribution over a wide range, but what it will have is an infinite period as it's based on external events. You can fix the distribution problem with a secure hash of your choice. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited.