Date: Mon, 10 Sep 2012 22:28:56 +0200 From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> To: Doug Barton <dougb@FreeBSD.org> Cc: Arthur Mesh <arthurmesh@gmail.com>, freebsd-rc@freebsd.org, freebsd-security@freebsd.org, RW <rwmaillists@googlemail.com>, Xin Li <delphij@delphij.net> Subject: Re: svn commit: r239569 - head/etc/rc.d Message-ID: <864nn5tyev.fsf@ds4.des.no> In-Reply-To: <504E4765.1020909@FreeBSD.org> (Doug Barton's message of "Mon, 10 Sep 2012 13:02:45 -0700") References: <50450F2A.10708@FreeBSD.org> <20120903203505.GN1464@x96.org> <50451D6E.30401@FreeBSD.org> <20120903214638.GO1464@x96.org> <50453686.9090100@FreeBSD.org> <20120904220754.GA3643@server.rulingia.com> <20120906174247.GB13179@dragon.NUXI.org> <20120906230157.5307a21f@gumby.homeunix.com> <20120906224703.GD89120@x96.org> <20120907015157.GA29497@server.rulingia.com> <20120910135218.GA68128@dragon.NUXI.org> <504E343A.4020802@FreeBSD.org> <86pq5tu1zr.fsf@ds4.des.no> <504E3DAB.3090000@FreeBSD.org> <86fw6pu0l0.fsf@ds4.des.no> <504E4765.1020909@FreeBSD.org>
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Doug Barton <dougb@FreeBSD.org> writes: > 3. Write a script to reboot, and once the system is fully booted do 'dd > if=3D/dev/random of=3Dsaved-random-out.$i count=3D4096' then reboot again > immediately. Values of i from 1 to 10,000 ought to do it. > 4. sha256 the saved-random-out files and see how many duplicates there ar= e. I doubt there will be any exact duplicates, but closer statistical analysis might reveal a slight bias. For instance, if my intuition serves, the Hamming distance between any pair of samples, when averaged over a large number of samples, should be half the sample length. I'm sure a professional statistician or cryptanalyst could come up with more accurate ways of detecting bias. The script in question, by the way, could simply be a few extra lines at the end of /etc/rc.d/initrandom; and I'd do it in a VM, to reduce cycle time to a minimum. DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no
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