From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1LdBpC-0001Mp-5A for mharc-grub-devel@gnu.org; Fri, 27 Feb 2009 18:08:58 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LdBpA-0001KG-Jf for grub-devel@gnu.org; Fri, 27 Feb 2009 18:08:56 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LdBpA-0001JZ-2c for grub-devel@gnu.org; Fri, 27 Feb 2009 18:08:56 -0500 Received: from [199.232.76.173] (port=49137 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LdBp9-0001JQ-UK for grub-devel@gnu.org; Fri, 27 Feb 2009 18:08:55 -0500 Received: from aybabtu.com ([69.60.117.155]:42490) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LdBp9-00049e-LS for grub-devel@gnu.org; Fri, 27 Feb 2009 18:08:55 -0500 Received: from [192.168.10.10] (helo=thorin) by aybabtu.com with esmtp (Exim 4.69) (envelope-from ) id 1LdBhz-00072X-Up for grub-devel@gnu.org; Sat, 28 Feb 2009 00:01:32 +0100 Received: from rmh by thorin with local (Exim 4.69) (envelope-from ) id 1LdBp5-0004QX-Ik for grub-devel@gnu.org; Sat, 28 Feb 2009 00:08:51 +0100 Date: Sat, 28 Feb 2009 00:08:51 +0100 From: Robert Millan To: The development of GRUB 2 Message-ID: <20090227230851.GC7907@thorin> References: <49A152BD.6010907@student.ethz.ch> <20090227204226.GI31629@thorin> <49A861A0.2000601@student.ethz.ch> <20090227222230.GA7907@thorin> <49A86F7B.8030201@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49A86F7B.8030201@gmail.com> Organization: free as in freedom X-Message-Flag: Worried about Outlook viruses? Switch to Thunderbird! www.mozilla.com/thunderbird X-Debbugs-No-Ack: true User-Agent: Mutt/1.5.18 (2008-05-17) X-detected-operating-system: by monty-python.gnu.org: Genre and OS details not recognized. Subject: Re: GRUB hardened boot framework X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Feb 2009 23:08:56 -0000 On Fri, Feb 27, 2009 at 11:55:55PM +0100, phcoder wrote: >> >> I'm no crypto expert, but I was under the impression that when the data is >> encrypted, measurement comes "for free": if someone tampered it, you'd be >> unable to decrypt. Is this correct? >> > It's not. Encryption is permutation > E_{key,sector} (P) -> C > Which permutes transforms plaintext P to ciphertext P. Without knowing > the key an attacker still can reuse the values he has already seen (e.g. > if he has an image of FS at previous date). > He can also replace the sector with anything. He can't predict to what > it will be decrypted but not to what it originally was I stand corrected; But in that case, measurement can still be implemented at the filesystem level? -- Robert Millan The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and how) you may access your data; but nobody's threatening your freedom: we still allow you to remove your data and not access it at all."