Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 28 Dec 2002 10:52:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 28 Dec 2002 10:52:23 -0500 Received: from [81.2.122.30] ([81.2.122.30]:5125 "EHLO darkstar.example.net") by vger.kernel.org with ESMTP id ; Sat, 28 Dec 2002 10:52:23 -0500 From: John Bradford Message-Id: <200212281600.gBSG0P4r001160@darkstar.example.net> Subject: Re: Want a random entropy source? To: list@fluent2.pyramid.net (Stephen Satchell) Date: Sat, 28 Dec 2002 16:00:25 +0000 (GMT) Cc: linux-kernel@vger.kernel.org In-Reply-To: <5.2.0.9.0.20021228073445.01d386c0@fluent2.pyramid.net> from "Stephen Satchell" at Dec 28, 2002 07:40:29 AM X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1047 Lines: 24 > I was astonished to see that the resulting signal is a white-noise > pattern with a slight emphasis at the high end (when sampled at 44 > kilosamples per second). In short, it looks like diode noise with a > 4 kilohertz square wave thrown in. > "That suggests to me that this would make a fair source of random samples, > especially after you slot out the interfering signal. How can you guarantee that you are sampling noise, though, what if a sound card was picking up 50 Hz mains hum, for example, that would de-randomise the data quite a bit. > "How many computers don't have cheap sound cards and CD-ROM drives?" I have never understood how a 16-bit DAC or ADC can have noise above 96 dB. Surely _by definition_ a 16-bit DAC or ADC is one that does not have noise above that level. John. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/