[dm-crypt] UUID question

Arno Wagner arno at wagner.name
Tue Dec 18 01:36:12 CET 2012

On Mon, Dec 17, 2012 at 04:10:50PM -0800, David Li wrote:
> Hi, I wonder if the dm-crypt partition UUID (shown in blkid -p <dev>) can
> be used to uniquely associate it with the set of keys the partition will
> need. Are there any cases that the UUID would change during the partition's
> lifetime?

The UUID is actually a filesystem attribute, not a partition 
attribute. That said, for purpose of an UUID, LUKS is regarded as a 
filesystem, which is IMO the correct way to view it, but not a 
perfect one. So, yes, the UUID will change if you do a luksFormat 
(aptly named if LUKS is regarded as a filesystem), but it will not 
change otherwise. As a luksFormat invalidates all keys, that should 
do for your purpose. 

Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
One of the painful things about our time is that those who feel certainty
are stupid, and those with any imagination and understanding are filled
with doubt and indecision. -- Bertrand Russell

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