[dm-crypt] extracting master key from luks header, cryptsetup

Milan Broz mbroz at redhat.com
Wed May 4 08:11:21 CEST 2011


On 05/03/2011 10:50 PM, anirudh wrote:
> Is there a way to extract the master key from luks header if we have the key or
> pass-phrase used to encrypt the volume using cryptsetup?

If you want to really backup master key (and not the whole header with known
keyslot with luksHeaderBackup) use "luksDump --dump-master-key" command
(available in cryptsetup 1.2.0, passphrase for some keyslot is required).

(Also you can activate device and save the mapping table with master key
with "dmsetup table --showkeys <active device>".)

Milan


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