On Thu, 22 Apr 2004 00:40, Valdis.Kletnieks@xxxxxx wrote: > I think the basic concept there is that even without a microphone, as you > sample, most cards won't return a steady stream of exact zeros - you'll get > back the tiniest bit of background hiss, and the low-order bits have > entropy. > > Of course, doing this without filtering is a Bad Idea - the amount of > entropy coming off the always-on cheap sound card in my laptop that has > maybe 70db S/N is probably a lot higher than somebody who has a high-end > card that has 85db S/N - and if their card supports auto-muting for unused > inputs, you're basically screwed... Detecting an auto-mute input should be quite easy, just read for a second or two and see if there is any change in the signal. Also writing non-random data to /dev/random is supposed to not cause any problems. -- http://www.coker.com.au/selinux/ My NSA Security Enhanced Linux packages http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/~russell/ My home page
