From owner-freebsd-security@FreeBSD.ORG Sun Sep 23 00:38:07 2012 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ABBD6106566C; Sun, 23 Sep 2012 00:38:07 +0000 (UTC) (envelope-from mariusz.gromada@gmail.com) Received: from mail-wi0-f178.google.com (mail-wi0-f178.google.com [209.85.212.178]) by mx1.freebsd.org (Postfix) with ESMTP id B0DCD8FC14; Sun, 23 Sep 2012 00:38:06 +0000 (UTC) Received: by wibhr14 with SMTP id hr14so2693271wib.13 for ; Sat, 22 Sep 2012 17:37:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=ufdsKVKr955c+N8jr8llD68sQqaBiMZm1x21LYxwSrU=; b=o9pi9mgdZx42y4VKN0Ikq7m/luogvl2/jGHKZczEJCcCBU2RptPYW4snqy/ddqqko7 6OT1cIiJnTGRya1rT5IJ0l3MqfYy+Z5HkasoSNPRulkBNn5DFvXUUmlPeEdt49kDtnlp JOLGMBeNoibgOWBGTA7Y62K0mJPiToXOsXmNssbs2WaDvDDS7n9f4HeJ28LqMJjpU+eP rrjUzmeZUXpBDpbMH56vO1BL0EAK7UIYrlhkTDB2zMzYJwcPFiFDcge/dEcfkae1qOSa Z7Gb60IuuqEBjJJYLLA9UQJQnXKg1hIV2rcpxEXhnVOIdJb8G4IHTcf027DHUrU5UFYC ZRng== Received: by 10.180.94.164 with SMTP id dd4mr5587491wib.1.1348360679817; Sat, 22 Sep 2012 17:37:59 -0700 (PDT) Received: from [192.168.1.100] (89-76-147-86.dynamic.chello.pl. [89.76.147.86]) by mx.google.com with ESMTPS id cu1sm6401764wib.6.2012.09.22.17.37.58 (version=SSLv3 cipher=OTHER); Sat, 22 Sep 2012 17:37:59 -0700 (PDT) Message-ID: <505E59DC.7090505@gmail.com> Date: Sun, 23 Sep 2012 02:37:48 +0200 From: Mariusz Gromada User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20120907 Thunderbird/15.0.1 MIME-Version: 1.0 To: Pawel Jakub Dawidek References: <20120918211422.GA1400@garage.freebsd.pl> <20120919231051.4bc5335b@gumby.homeunix.com> <20120920102104.GA1397@garage.freebsd.pl> <201209200758.51924.jhb@freebsd.org> <20120922080323.GA1454@garage.freebsd.pl> <20120922195325.GH1454@garage.freebsd.pl> In-Reply-To: <20120922195325.GH1454@garage.freebsd.pl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Sun, 23 Sep 2012 01:56:03 +0000 Cc: Ben Laurie , freebsd-security@freebsd.org, RW , Jonathan Anderson , John Baldwin Subject: Re: Collecting entropy from device_attach() times. X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 23 Sep 2012 00:38:07 -0000 W dniu 2012-09-22 21:53, Pawel Jakub Dawidek pisze: > Mariusz, can you confirm my findings? Pawel, Your conclusions can be easily confirmed by shape analysis of the EDF. Usually maximum quantile difference (called D-statistic) gives you a kind of overview, function shape gives you a strong feeling, p-value gives you a formal proof. D-statistic values (your data): 6bit: 0.33% 7bit: 0.29% 8bit: 0.27% 9bit: 0.21% 10bit: 6.34% 11bit: 19.07% 12bit: 54.80% What I would say: increasing the number of bits from 6 to 9 does not affect distribution "uniformity", reaching the tenth bit results in sudden increase in the difference measure - the more bits, the more difference is observed. Distribution shape analysis for the 10th bit shows non-linear function. Lack of "randomness" in the quntile difference curve - chart shows completely lack of noise (pure functional relation). These are very strong indicators that starting from 10th bit distribution was changed and is no longer uniform. To formally confirm above conclusion for i.e. 5% significance level, which means that confidence level is 95%, I need some extra data regarding sample sizes. Please pass to me number of collected observations in each 6-12 bit experiment. Regards, Mariusz