[dm-crypt] Encrypted Raid1 or Raid 1 of encrypted devices?

Arno Wagner arno at wagner.name
Thu Jul 14 15:42:40 CEST 2011

On Thu, Jul 14, 2011 at 09:41:58PM +1000, Roscoe wrote:
> On Thu, Jul 14, 2011 at 9:01 PM, Arno Wagner <arno at wagner.name> wrote:
> ...
> > I thing your risk model is wrong. Basically it covers attacks
> > were the attacker has access to only the storage and at the same
> > time can actually do something serious with data manipulation.
> > That is a rather unlikely scenario for disk encryption. Note that
> > for communication encryption, this is a real and valid scenario.
> Given the prevalence of of iSCSI, FC and similar, I wouldn't say it's
> all that unlikely.

That would be transport security. If you have a real, externally
exposed to attackers transport device (e.g. a network cable), 
then you leave the area of storage encryption and need to do network
> I for one would quite like assurances that network block device
> providers couldn't impact my security. But, I imagine I'll have to
> wait a while longer...

If you, say, tunnel your network block device over SSH
(or some other VPN) and use, e.g. LUKS on the storage layer
in your local machine, you will be pretty secure.

But you need to realize that storage encryption and 
communication encryption are two different things and have
to be done separately. As one example, to illustrate this,
consider that for CBC, you have to have different 
upredictable, but not secret, IVs per connection, while
in disk encryption you need to have the same IV per
block and the IVs should not be publicly known. Entirely
different requirements, resulting from the different
nature of the problem.

Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno at wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
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