I have Ubuntu 18.04 installed on my UEFI machine. I want to change the passphrase of my luks encrypted volume. I already know the commands of how to do this. However I don't know which device I need to choose for changing the key ? The EFI parition which is smaller than 1GB or the root partition which takes the whole space of the system ?
1 Answer
Usually you would have an unencrypted /boot
and an extended partition (sda2 in this example) which have inside the LUKS partition. In this case is sda5
$ lsblk # check also with lsblk -f
sda 8:0 0 931,5G 0 disk
├─sda1 8:1 0 731M 0 part /boot
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 930,8G 0 part
└─sda5_crypt 253:0 0 930,8G 0 crypt
├─ubuntu--vg-root 253:1 0 929,8G 0 lvm /
└─ubuntu--vg-swap_1 253:2 0 976M 0 lvm [SWAP]
$ sudo cryptsetup isLuks -v /dev/sda5
Command successful.
sudo cryptsetup luksDump /dev/sda5
for cipher name, mode, and more info.