Re: [dm-crypt] Authenticated Encryption for dm-crypt

[Arno Wagner <arno@wagner.name>]

I am not really sure what you mean. 

Per-sector authenticatipn is infeasible as it requires 
additional space. This is not communication encryption
where attaching a few bytes is possible. This is disk
encryption where 512 encrypted bytes have to fit exactly
into 512 bytes of space. 

Do you mean the header should authenticate itself to the 
user in decryption? That would only make sense if a 
malicious disk encryption system is assumed and would 
have to be done before the passphrase is given. The
attacker model would be something like disk-impersonation
gere or a cryptsetup or kernel that tries to steal the
passphrase.

Arno


On Tue, May 21, 2013 at 12:31:09AM +0200, Ralf Ramsauer wrote:
> Hi,
> 
> are there any weighty reasons why there is no support for authenticated
> encryption for
> dm-crypt or did simply no one want to implement it up to now? :-)
> 
> Did anyone do any work on this topic up to now? I think authenticated
> encryption would
> be a nice feature.
> 
> Regards
> 
> -- 
> Ralf Ramsauer
> 
> PGP: 0x8F10049B
> 
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-- 
Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno@wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
There are two ways of constructing a software design: One way is to make it
so simple that there are obviously no deficiencies, and the other way is to
make it so complicated that there are no obvious deficiencies. The first
method is far more difficult.  --Tony Hoare