From owner-freebsd-geom@FreeBSD.ORG Thu Dec 2 16:06:32 2004 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 196DE16A4CE for ; Thu, 2 Dec 2004 16:06:32 +0000 (GMT) Received: from foo.nemo-project.org (foo.nemo-project.org [194.54.103.89]) by mx1.FreeBSD.org (Postfix) with ESMTP id 73B3A43D45 for ; Thu, 2 Dec 2004 16:06:31 +0000 (GMT) (envelope-from terje@elde.org) Received: by foo.nemo-project.org (Postfix, from userid 1001) id 0954ED9091; Thu, 2 Dec 2004 17:07:52 +0100 (CET) Date: Thu, 2 Dec 2004 17:07:52 +0100 From: Terje Elde To: Ivan Voras Message-ID: <20041202160752.GV72822@calleigh.elde.net> References: <41AE1B68.5040003@fer.hr> <20041202140527.GT72822@calleigh.elde.net> <41AF3BE9.8050108@fer.hr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41AF3BE9.8050108@fer.hr> User-Agent: Mutt/1.5.4i cc: freebsd-geom@freebsd.org Subject: Re: More geom classes? X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Dec 2004 16:06:32 -0000 On Thu, Dec 02, 2004 at 04:59:37PM +0100, Ivan Voras wrote: > >One thing that would be funny is GEOM XOR, with the possability of setting > >up two (or more) volumes, such that you write random bytes to one drive, > >and write the data xored with the random to the other. > > I could easily do that with ggate for fun, if somebody'll use it :) (Of > course, performance will probably suck, it being in userland...) ggate would be one option, but it'd be much nicer to have it as a 'real' geom module. > >Introduce RAID3 or 5 and add an extra disk, and you've for N-1 of M > >redundancy in your heavily encrypted volume. ;) > > Oh yes :) > > A password will still be required, for generating the random sequence... *cringe* The only point of using such a XOR is to end up with an effective OTP (One Time Pad). If you use a password as seed for a simple PRNG, then you're throwing away all the gain, and would be better off with GEOM BDE instead. FreeBSD 5 has a seemingly very good yarrow-based entropy source. Why not use that? The only known perfect encryption algorithm is OTP, assuming your input is perfectly random. If you use a seeded PRNG, then you'd end up reducing the security to that of a regular stream cipher. Terje