Linux RNG paper

[Victor Duchovni]

On Thu, May 04, 2006 at 01:44:48PM -0500, Travis H. wrote:

> I guess perhaps the reason they don't do integrity checking is that it
> involves redundant data, so the encrypted volume would be smaller, or
> the block offsets don't line up, and perhaps that's trickier to handle
> than a 1:1 correspondence.

Exactly, many file systems rely on block devices with atomic single block
(sector) writes. If sector updates are not atomic, the file system needs
to be substantially more complex (unavoidable transaction logs to support
roll-back and roll-forward). Encrypted block device implementations that
are file system agnostic, cannot violate block update atomicity and so
MUST not offer integrity.

-- 

 /"\ ASCII RIBBON                  NOTICE: If received in error,
 \ / CAMPAIGN     Victor Duchovni  please destroy and notify
  X AGAINST       IT Security,     sender. Sender does not waive
 / \ HTML MAIL    Morgan Stanley   confidentiality or privilege,
                                   and use is prohibited.

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at metzdowd.com