From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 19 Aug 2001 18:30:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 19 Aug 2001 18:30:01 -0400 Received: from mail.webmaster.com ([216.152.64.131]:57280 "EHLO shell.webmaster.com") by vger.kernel.org with ESMTP id ; Sun, 19 Aug 2001 18:30:00 -0400 From: "David Schwartz" To: "Alex Bligh - linux-kernel" Cc: "Oliver Xymoron" , Subject: RE: Entropy from net devices - keyboard & IDE just as 'bad' [was Re: [PATCH] let Net Devices feed Entropy, updated (1/2)] Date: Sun, 19 Aug 2001 15:30:13 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) In-Reply-To: <481261630.998262525@[169.254.45.213]> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2479.0006 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > $ cat /proc/interrupts > CPU0 > 0: 1116302985 XT-PIC timer > 1: 2 XT-PIC keyboard > 2: 0 XT-PIC cascade > 8: 1 XT-PIC rtc > 9: 28980016 XT-PIC usb-uhci, eth0 > 14: 698146587 XT-PIC ide0 > 15: 5 XT-PIC ide1 > NMI: 0 > ERR: 0 > > Shock horror - I can continually poll this and spot > when an IRQ occurs. To what level of accuracy do you think you can measure when interrupts occur? From my tests, you can (if you max the processor and do no math on the results) read /proc/interrupts about once every 30,000 instruction cycles. This would still leave about 14 bits of entropy in each interrupt. Overall, you're just making the system busier. DS