From: Herbert Xu Subject: Re: [PATCH] dm-crypt: disable block encryption with arc4 Date: Wed, 10 Feb 2010 07:45:19 +1100 Message-ID: <20100209204519.GC26258@gondor.apana.org.au> References: <20100209073718.GA17612@gondor.apana.org.au> <20100209145705.GA20421@Chamillionaire.breakpoint.cc> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Mikulas Patocka , mbroz@redhat.com, linux-crypto@ml.breakpoint.cc, dm-devel@redhat.com, agk@redhat.com, linux-crypto@vger.kernel.org To: Sebastian Andrzej Siewior Return-path: Received: from rhun.apana.org.au ([64.62.148.172]:37899 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752046Ab0BIUpX (ORCPT ); Tue, 9 Feb 2010 15:45:23 -0500 Content-Disposition: inline In-Reply-To: <20100209145705.GA20421@Chamillionaire.breakpoint.cc> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, Feb 09, 2010 at 03:57:05PM +0100, Sebastian Andrzej Siewior wrote: > > >As to blacklisting algorithms not suitable for disk encryption, > >that is up to the dm-crypt maintainers to decide. > > Herbert, what happend to the "check for streamcipher" idea you had? Is > it gone? On the other hand it wouldn't be probably that bad to have a Well again whether that should be done is up to the dm-crypt maintainers. > seprate interface to grab a block cipher _or_ a stream cipher. So Just because something isn't a stream cipher doesn't mean that it is safe for disk encryption. People simply shouldn't be using random algorithms for disk encryption. > I can't imaging how you want to fix arc4 that it will work in dm-crypt. I thought I've explained this before. Just turn it into a blkcipher and add IV. > The algorithm relies more or less on the fact that it envolves itself > during processing of data. This is no different to any stream cipher. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt