Random tips, tricks, and musings from your local technophile

LUKS passphrases: Changing, adding, removing

Recently we went over how to manually encrypt volumes in Linux. Today let’s talk a little bit about how to change, add, or remove passphrases. We’ll start by changing our current passphrase by first dropping down to init 3 and unmounting the encrypted volume before making the change. During this exercise we will need to be root, and I will be using the same encrypted volume that was built in the previous post.

init 3
umount /home
cryptsetup luksClose home
cryptsetup luksChangeKey /dev/vg00/lv02
< verify and change your passphrase here>
cryptsetup luksOpen /dev/vg00/lv02 home
mount /home

LUKS allows for up to 8 passwords to exist for a given partition, so let’s add one and then close and re-open it to verify that it worked.

cryptsetup luksAddKey /dev/vg00/lv02
< enter any current phrase - and add new phrase >
umount /home
cryptsetup luksClose home
cryptsetup luksOpen /dev/vg00/lv02 home
< enter our new passphrase >
mount /home

Now lets say you don’t want that passphrase anymore and you want to remove it.

*NOTE* If you delete the last working passphrase there is no way to recover your data. If you try this you are warned before committing to it.

umount /home
cryptsetup lulsClose home
cryptsetup luksRemoveKey /dev/vg00/lv02
< enter the passphrase you want to remove >
cryptsetup luksOpen /dev/vg00/lv02 home
< enter the the one you removed, to verify that it is gone >
mount /home

2 responses to “LUKS passphrases: Changing, adding, removing

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