Date: Sun, 23 Sep 2012 17:17:06 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Mariusz Gromada <mariusz.gromada@gmail.com> Cc: Ben Laurie <benl@freebsd.org>, freebsd-security@freebsd.org, RW <rwmaillists@googlemail.com>, Jonathan Anderson <jonathan.anderson@cl.cam.ac.uk>, John Baldwin <jhb@freebsd.org> Subject: Re: Collecting entropy from device_attach() times. Message-ID: <20120923151706.GN1454@garage.freebsd.pl> In-Reply-To: <505E59DC.7090505@gmail.com> 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> <505E59DC.7090505@gmail.com>
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[-- Attachment #1 --] On Sun, Sep 23, 2012 at 02:37:48AM +0200, Mariusz Gromada wrote: > 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. Total number of observations was 162833. -- Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlBfJ/IACgkQForvXbEpPzQJ+wCbBzLCJZkjhz6vQr0MuBiXXEqT HiIAnj9DLk6BvR+JiGmlUOviNaKY5Rhk =DrJs -----END PGP SIGNATURE-----
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