Re: [dm-crypt] please HELP - can't acces encrypted LVM after linux reinstallation.

From: Arno Wagner <arno@wagner.name>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] please HELP - can't acces encrypted LVM after linux reinstallation.
Date: Fri, 28 Oct 2011 18:24:28 +0200	[thread overview]
Message-ID: <20111028162428.GA26437@tansi.org> (raw)
In-Reply-To: <CAP8O3oN0vb+gpgRPMS06q0qrih9ouPJBgSguotS6LxYxip1=ew@mail.gmail.com>

As LUKS is specifically designed with anti-forensic features,
a "trace" would not help at all. In fact changing a few bits 
in the keyslots in random locations is quite enough to 
make the data inacessible permanently. As others have said,
without header backup there is no way.

Side note: Encryption does not remove the need for backup.
In fact, the FAQ discusses several encrypted backup options.

Arno

On Sat, Oct 29, 2011 at 05:05:59AM +1300, Aleksander Swirski wrote:
> thank you for your replies. if someone knows, if it's possible to find some
> trace of old header under the new one ... please let me know. if it's
> definitely not possible ... please let me know. the crypt partition wasn't
> moved or resized, also the home logical volume, which I lost was
> 'continuous' and wasn't moved or resized.
> 
> On 29 October 2011 05:03, Arno Wagner <arno@wagner.name> wrote:
> 
> > On Fri, Oct 28, 2011 at 05:53:48PM +0200, Marc Ballarin wrote:
> > > Am Samstag, den 29.10.2011, 04:23 +1300 schrieb Aleksander Swirski:
> > > ...
> > > > I now realize what might have happened. As I explained I set up same
> > > > passphrase again on this crypt disk when installing new system. But I
> > > > suspect, encryption key underneath could be changed and LVM is now
> > > > scrambled?
> > >
> > > Yes, if you used LUKS this is exactly what happened. cryptsetup created
> > > a new, random master key and wrote it over your old master key.
> >
> > I wonder whether I should as a warning about this at the beginning
> > of the FAQ.
> >
> > Arno
> > --
> > Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email:
> > arno@wagner.name
> > GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25
> > 338F
> > ----
> > Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
> >
> > If it's in the news, don't worry about it.  The very definition of
> > "news" is "something that hardly ever happens." -- Bruce Schneier
> > _______________________________________________
> > dm-crypt mailing list
> > dm-crypt@saout.de
> > http://www.saout.de/mailman/listinfo/dm-crypt
> >

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-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier 