From owner-freebsd-questions@FreeBSD.ORG Thu Sep 13 20:58:03 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1863616A419 for ; Thu, 13 Sep 2007 20:58:03 +0000 (UTC) (envelope-from peo@intersonic.se) Received: from neonpark.inter-sonic.com (neonpark.inter-sonic.com [212.247.8.98]) by mx1.freebsd.org (Postfix) with ESMTP id CA58413C457 for ; Thu, 13 Sep 2007 20:58:02 +0000 (UTC) (envelope-from peo@intersonic.se) X-Virus-Scanned: amavisd-new at inter-sonic.com Message-ID: <46E9A455.4090703@intersonic.se> Date: Thu, 13 Sep 2007 22:57:57 +0200 From: Per olof Ljungmark Organization: Intersonic AB User-Agent: Thunderbird 2.0.0.6 (X11/20070814) MIME-Version: 1.0 To: freebsd-questions@freebsd.org References: <46E94F9A.6050707@intersonic.se> <20070913153630.GA9448@slackbox.xs4all.nl> <20070913173155.0bad12b2@gumby.homeunix.com.> <20070913174537.GA11683@slackbox.xs4all.nl> In-Reply-To: <20070913174537.GA11683@slackbox.xs4all.nl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: /dev/random question 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: Thu, 13 Sep 2007 20:58:03 -0000 Roland Smith wrote: > On Thu, Sep 13, 2007 at 05:31:55PM +0100, RW wrote: >> On Thu, 13 Sep 2007 17:36:30 +0200 >> Roland Smith wrote: >> >>> On Thu, Sep 13, 2007 at 04:56:26PM +0200, Per olof Ljungmark wrote: >>>> Hi, >>>> >>>> Could someone on the list point me to a document that explains the >>>> functionality of /dev/random in FreeBSD in a little more depth than >>>> the man page? In other OS's I've looked at random and urandom are >>>> different, here it's a symlink (talking about RELENG-6 onwards). >>> >>> FreeBSD uses the yarrow algorithm, as mentioned in random(4). See >>> http://en.wikipedia.org/wiki/Yarrow_algorithm >>> http://www.schneier.com/yarrow.html >> Yarrow is reseeded with interrupt entropy, and is supposedly good >> enough not to require the amount of entropy to be tracked. >> So /dev/random need not block, and there's no need for a separate >> non-blocking device. > > On the website it says that the original yarrow algorithm is no longer > supported. It seems to have been replaced by the fortuna algorithm. > > I can't see from the source if /usr/src/sys/dev/random/yarrow.* use the > original yarrow algorithm, or the improved yarrow-160 aka fortuna. The use of > crypto/rijndael/rijndael-api-fst.h and crypto/sha2/sha2.h seem to > indicate the latter though. Should I conclude then that randomness is sufficient and performance is a non-issue?