From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 2 Feb 2002 16:03:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 2 Feb 2002 16:03:01 -0500 Received: from [195.63.194.11] ([195.63.194.11]:54277 "EHLO mail.stock-world.de") by vger.kernel.org with ESMTP id ; Sat, 2 Feb 2002 16:02:58 -0500 Message-ID: <3C5C53F5.1030401@evision-ventures.com> Date: Sat, 02 Feb 2002 22:02:45 +0100 From: Martin Dalecki User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020129 X-Accept-Language: en-us, pl MIME-Version: 1.0 To: David Wagner CC: linux-kernel@vger.kernel.org Subject: Re: Continuing /dev/random problems with 2.4 In-Reply-To: <20020201031744.A32127@asooo.flowerfire.com> <1012582401.813.1.camel@phantasy> <20020201202334.72F921C5@www.pmonta.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David Wagner wrote: >Peter Monta wrote: > >>Many motherboards have on-board sound. Why not turn the mic >>gain all the way up and use the noise---surely there will be >>a few bits' worth? >> > >That may be reasonable, but beware: there are some potential pitfalls. >For instance, is there a risk that the audio data you read is strongly >correlated to 60Hz mains noise in some scenarios? Also, my understanding >is that the quality of randomness you get can depend on which sound card >you have, and moreover that the left and right channels can be strongly >correlated (audio-entropyd takes the difference between the two). >I think there are some things you can do, but it seems that one might >want to be a bit careful here. > There is no need to speculate here - just please do aan autocorrelation of the signal with grace for example and laugh at the idea ;-).