From owner-freebsd-security@FreeBSD.ORG Fri Sep 21 23:20:34 2012 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A265D106566C for ; Fri, 21 Sep 2012 23:20:34 +0000 (UTC) (envelope-from des@des.no) Received: from smtp.des.no (smtp.des.no [194.63.250.102]) by mx1.freebsd.org (Postfix) with ESMTP id 625048FC0A for ; Fri, 21 Sep 2012 23:20:34 +0000 (UTC) Received: from ds4.des.no (smtp.des.no [194.63.250.102]) by smtp.des.no (Postfix) with ESMTP id 756E566D1; Sat, 22 Sep 2012 01:20:33 +0200 (CEST) Received: by ds4.des.no (Postfix, from userid 1001) id 466A08D84; Sat, 22 Sep 2012 01:20:33 +0200 (CEST) From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= To: RW References: <20120918211422.GA1400@garage.freebsd.pl> <867grqm3pt.fsf@ds4.des.no> <20120919184758.28589516@gumby.homeunix.com> <86sjadt677.fsf@ds4.des.no> <20120920230133.55b63dea@gumby.homeunix.com> Date: Sat, 22 Sep 2012 01:20:32 +0200 In-Reply-To: <20120920230133.55b63dea@gumby.homeunix.com> (RW's message of "Thu, 20 Sep 2012 23:01:33 +0100") Message-ID: <86lig3arpb.fsf@ds4.des.no> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Cc: freebsd-security@freebsd.org 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: Fri, 21 Sep 2012 23:20:34 -0000 RW writes: > They key will therefore *accumulate* entropy across multiple reseeds. Forgot to address this. By definition, there can never be more entropy in Yarrow than the key size. So it *does* throw away entropy in the sense that if it accumulated, say, 900 bits of entropy pre-boot (to pick one of the numbers Pawel cited), 650 of them are wasted. DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no