[dm-crypt] please HELP - can't acces encrypted LVM after linux reinstallation.

Marc Ballarin Ballarin.Marc at gmx.de
Fri Oct 28 17:53:48 CEST 2011

Am Samstag, den 29.10.2011, 04:23 +1300 schrieb Aleksander Swirski:
> I now realize what might have happened. As I explained I set up same
> passphrase again on this crypt disk when installing new system. But I
> suspect, encryption key underneath could be changed and LVM is now
> scrambled?

Yes, if you used LUKS this is exactly what happened. cryptsetup created
a new, random master key and wrote it over your old master key.

Keeping data by using the same password to create a new mapping only
works for plain cryptsetup without any header. With LUKS (and similar
schemes like Truecrypt) passwords are completely unrelated to the master
key which is used for actual data encryption.

> I didn't back up many important files, because my other drive
> failed not long time ago and didn't get new one yet due to cash shortage. Is
> there any hope? PLEASE if anybody can help me. Is it possible to regain
> acces to this LVM?

Unless you have a backup of your old header there really isn't anything
you can do.

Your password unlocks the master key which in turn unlocks the data. But
you have overwritten your old master key :-(

I hope you will find a header backup or someone else has an idea where
the old master key might still be found...


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