From: Ralf Ramsauer <ralf+dm@ramses-pyramidenbau.de>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] How to derive master key in plain dm-crypt mode
Date: Wed, 10 Dec 2014 17:56:01 +0200 [thread overview]
Message-ID: <54886D11.60908@ramses-pyramidenbau.de> (raw)
In-Reply-To: <CAKXMRqhLuWAVaC9YxYziTKvZxRB3XmqXdhDbdYnDrQT-XJL+YA@mail.gmail.com>
On 12/10/2014 01:48 PM, Jian-Ming Zheng wrote:
> Hi,
>
> In plain dm-crypt mode, there is no encrypted master key on the device
> (i.e., no metadata header). Is a master key derived from the user
> passphrase and used to en-/decrypt the device? If yes, how to derive
> the master key from the passphrase in plain mode?
Hi,
No.
In short words and to sum it up:
The passphrase is used to generate some "intermediate" key, using a Key
Derivation Function. In case of Luks, this function is PBKDF2.
This derived key is used to decrypt a Keyslot in the Luks header of your
volume, which contains the actual masterkey.
So having only the passphrase is not sufficient to derive a volume's
masterkey.
cheers
Ralf
>
> Thanks.
> _______________________________________________
> dm-crypt mailing list
> dm-crypt@saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt
next prev parent reply other threads:[~2014-12-10 15:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 11:48 [dm-crypt] How to derive master key in plain dm-crypt mode Jian-Ming Zheng
2014-12-10 15:56 ` Ralf Ramsauer [this message]
2014-12-10 16:01 ` Ralf Ramsauer
2014-12-11 2:16 ` Jian-Ming Zheng
2014-12-10 22:34 ` Robert Nichols
2014-12-11 1:37 ` Arno Wagner
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