From owner-freebsd-hackers@FreeBSD.ORG Fri Mar 4 00:49:04 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C0CFB16A4CE for ; Fri, 4 Mar 2005 00:49:04 +0000 (GMT) Received: from snark.piermont.com (snark.piermont.com [166.84.151.72]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1847743D46 for ; Fri, 4 Mar 2005 00:49:04 +0000 (GMT) (envelope-from perry@piermont.com) Received: by snark.piermont.com (Postfix, from userid 1000) id 6A443D988C; Thu, 3 Mar 2005 19:49:03 -0500 (EST) To: "Poul-Henning Kamp" References: <12467.1109893619@critter.freebsd.dk> From: "Perry E. Metzger" Date: Thu, 03 Mar 2005 19:49:03 -0500 In-Reply-To: <12467.1109893619@critter.freebsd.dk> (Poul-Henning Kamp's message of "Fri, 04 Mar 2005 00:46:59 +0100") Message-ID: <877jkogrr4.fsf@snark.piermont.com> User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailman-Approved-At: Fri, 04 Mar 2005 16:36:07 +0000 cc: ALeine cc: tech-security@NetBSD.org cc: elric@imrryr.org cc: hackers@freebsd.org cc: ticso@cicely.de Subject: Re: FUD about CGD and GBDE X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Mar 2005 00:49:04 -0000 "Poul-Henning Kamp" writes: > In message <87d5ugi9ht.fsf@snark.piermont.com>, "Perry E. Metzger" writes: >>> MD5 was believed to be heavily understood in literature. It was >>> well established. Look at what happened to it. >> >>Yup. And Roland made the algorithm you use for encrypting your disk >>*pluggable*. That way, if AES is broken, you can replace it with the >>next big thing and move on with your life. >> >>Now, if AES is indeed broken, GBDE is in serious trouble, but CGD is >>not. Specific users of CGD have to change their drives, but the >>framework continues to work as advertised. > > Gee Perry, now you're spreading FUD. > > You know perfectly well that it would take less than one hour to > substitute another algorithm in the GBDE source code. But you aren't built for that from the get-go. I would strongly suggest you change that -- make your cipher a user configurable component. I also very strongly suggest that the biggest real threat you face isn't someone cracking AES but key management issues. CGD is in some sense largely a framework for letting you do all sorts of neat things with key management in a disk encryption context. You may want to add similar features -- the most practical attack against your system as it stands is a dictionary attack. -- Perry E. Metzger perry@piermont.com