geli external header (metadata)

[Pawel Jakub Dawidek]

On Sun, Jun 09, 2013 at 02:51:12PM -0500, Greg Rivers wrote:
> On Sun, 9 Jun 2013, Pawel Jakub Dawidek wrote:
> 
> > On Sat, Jun 08, 2013 at 03:02:10PM +0300, Andrew Romero wrote:
> > > Hi all
> > > I made a patch to support of external header (metadata) on GEOM ELI (geli)
> > > 
> > > System: FreeBSD 9-STABLE r250964 i386
> > > 
> > > geli patch - http://pastebin.com/UGpnMN19
> > > regresion patch - http://pastebin.com/hJVkTpJZ
> > 
> > I don't mean to discourage you, but every additional complexity comes at 
> > risk and it case of GELI this is security risk. What is missing in your 
> > work is explanation how it that useful for the users? How do you use it? 
> > First I need to understand and be convinced that this functionality is 
> > generally useful and thus is worth additional complexity and risk.
> >
> 
> I can't speak for Mr Romero, but I imagine what he's after is plausible 
> deniability.  The GELI metadata on a volume unambiguously declares it to 
> be encrypted data.
> 
> Properly implemented, I think this could be a worthwhile enhancement for 
> certain applications or circumstances where one may not wish to invite 
> further scrutiny.

That was my first guest too, but in that case I'd much prefer to have
this implemented without the need of storing metadata outside. I even
started implementing it some time ago, but run out of time before it was
done and dropped it.

To ensure plausible deniability using proposed change one has to store
metadata on removable device (like USB stick) and always remember to
remove it once GELI provider is attached. This requirement can be
avoided and avoiding it would significantly extend number of potential
users.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
FreeBSD committer                         http://www.FreeBSD.org
Am I Evil? Yes, I Am!                     http://mobter.com
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