From owner-freebsd-questions@FreeBSD.ORG Tue Aug 1 17:37:28 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9C14F16A4DA for ; Tue, 1 Aug 2006 17:37:28 +0000 (UTC) (envelope-from nikolas.britton@gmail.com) Received: from wx-out-0102.google.com (wx-out-0102.google.com [66.249.82.195]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1522B43D46 for ; Tue, 1 Aug 2006 17:37:28 +0000 (GMT) (envelope-from nikolas.britton@gmail.com) Received: by wx-out-0102.google.com with SMTP id i27so352652wxd for ; Tue, 01 Aug 2006 10:37:27 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ph43cZ1C/ZVTZYvJj1/3Ig/t0ow6qJtml6NbXghm3kp0vd3oXTzx2M6t1XmxMzY2lR5Bpu0mT6sgclXHTFjinTMhHbci91le95id3vfG9K0yCb3o3DaBKZ46hcLeuMdSy/rFD9UWQMmM6TTFU/ZU1EQv0b6aihoB56tQvhcmyL0= Received: by 10.78.193.19 with SMTP id q19mr383107huf; Tue, 01 Aug 2006 10:37:26 -0700 (PDT) Received: by 10.78.143.11 with HTTP; Tue, 1 Aug 2006 10:37:21 -0700 (PDT) Message-ID: Date: Tue, 1 Aug 2006 12:37:21 -0500 From: "Nikolas Britton" To: "Robert Huff" In-Reply-To: <17615.30414.314802.792740@jerusalem.litteratus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20060728164526.E27679@ganymede.hub.org> <20060730233839.I27679@ganymede.hub.org> <44CDAA98.3030702@freebsd.org> <44CDE02F.4090604@dial.pipex.com> <44CE7DD0.9070902@childeric.freeserve.co.uk> <871ws1v261.fsf@photon.homelinux.org> <20060731220830.B27679@ganymede.hub.org> <20060801120058.O27679@ganymede.hub.org> <17615.30414.314802.792740@jerusalem.litteratus.org> Cc: Xiao-Yong Jin , freebsd-questions@freebsd.org, User Freebsd Subject: Re: Gotta start somewhere ... how many of us are really out there? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Aug 2006 17:37:28 -0000 On 8/1/06, Robert Huff wrote: > User Freebsd writes: > > Actually, using ifconfig wouldn't work ... it would give unique, but as > > soon as you add another IP (ie. alias), the ID would change ... you'd need > > to do something like: > > > > ifconfig | grep ether | sha256 | md5 > > > > since the 'ether' would never change ... > > At least some cards (+ FreeBSD drivers) allow you to set the > MAC address .... > > > You still don't get it! Maybe this simple perl program will illustrate the problem: my $number = "100000000000000000000"; my $randomkey = ""; while (0 == 0) { $randomkey = `echo $number | md5`; print "fetch http://www.hub.org/freebsd_stats.php?HOSTID=$randomkey"; $number++ } Also by using only the mac address output of ifconfig you have limited the pool of unique keys to 16^12 (281,474,976,710,656)!!! All I need to do to find your mac address is compute all possible mac address combinations into MD5 and then just simply match it up with yours. Anonymity only works if the input is large then the output!!! Because it's computationally impossible to compute all values of a 500+ byte string etc. etc. The MD5 string maps back to at least (how do you compute the collisions?) two SHA256 keys and the SHA256 maps back to at least two ifconfig strings.