[dm-crypt] recovering forgotten passwords for 2 LVs

ken gebser at mousecar.com
Tue Aug 23 15:39:32 CEST 2011

On 08/23/2011 08:57 AM Arno Wagner wrote:
> On Mon, Aug 22, 2011 at 06:33:30PM -0400, ken wrote:
> [...] 
>> Yves, thanks for replying.
>> This setup worked fine for years without changing anything on it.  I'm
>> fairly certain that there are two logical volumes on /dev/sda5, both
>> encrypted.  As said, when I booted the system up, I was prompted for two
>> passphrases (one for each filesystem).
>> Does this tell us anything?
>> # cryptsetup luksDump /dev/sda5
>> LUKS header information for /dev/sda5
>> Version:        1
>> Cipher name:    aes
> [...]
> It does. /dev/sda5 has a LUKS container at the start with
> one passphrase active. For password breaking attempts, it 
> does not matter that there are some LVM mappings. I advise 
> to just ignore any LVM stuff for the moment and to run your 
> password guessing attempts against /dev/sda5. 
> You will possibly not get you data, but the password checking 
> will be good, unless that thing was created using 
> decrypt_derived or the like. I doubt that, as then you 
> should have been asked only for one password.
> Once you have the password recovered, you should be able
> to do a normal boot.
> Arno

Thanks!  That's good news.  I was specifically worried that my running
"cryptsetup luksOpen /dev/sda5 name" might not be accessing what it
should... and so that it would *never* succeed, even with the correct

Once I determine the correct passphrase (big hopes... I've already tried
a lot of them), I can take the drive out of the enclosure and install it
back in its original machine.  It should then boot properly.  (This is
Plan A anyway.)  :)

Best regards to all,

War is a failure of the imagination.
        --William Blake

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