Learn how to interactively manage LUKS passphrases on a specific device.
Display LUKS header
Display LUKS header information.
$ sudo cryptsetup luksDump /dev/sdb1
LUKS header information for /dev/sdb1
Version: 1
Cipher name: aes
Cipher mode: xts-plain64
Hash spec: sha256
Payload offset: 4096
MK bits: 256
MK digest: eb 33 45 89 95 2b 67 dd 65 6d 17 d3 ed 7d 05 c4 84 58 5f fc
MK salt: b7 0b c3 96 0e ab 70 1b f0 28 9f 39 63 a4 37 95
16 e0 61 e6 98 ab fc c1 18 db 1a 36 bc 00 bd 13
MK iterations: 151879
UUID: ac32a865-2716-43e3-8db9-798d4279a3a3
Key Slot 0: ENABLED
Iterations: 2430070
Salt: 10 a5 7d 29 c8 7f 21 d8 15 ca 42 08 01 a5 79 0c
d4 d7 5b 87 c3 14 cc 33 75 ec ec ba 71 26 8c 67
Key material offset: 8
AF stripes: 4000
Key Slot 1: DISABLED
Key Slot 2: DISABLED
Key Slot 3: DISABLED
Key Slot 4: DISABLED
Key Slot 5: DISABLED
Key Slot 6: DISABLED
Key Slot 7: DISABLED
Add an additional passphrase
Add an additional passphrase to the next free key-slot.
$ sudo cryptsetup luksAddKey /dev/sdb1 Enter any existing passphrase: ********** Enter new passphrase for key slot: ********** Verify passphrase: **********
You will receive an error in case that every key-slot is used.
$ sudo cryptsetup luksAddKey /dev/sdb1 Enter any existing passphrase: ********** Enter new passphrase for key slot: ********** Verify passphrase: ********** All key slots full.
Add an additional passphrase to the specified key-slot.
$ sudo cryptsetup luksAddKey --key-slot 7 /dev/sdb1 Enter any existing passphrase: ********** Enter new passphrase for key slot: ********** Verify passphrase: **********
You will receive an error in case that specified key-slot is already used.
$ sudo cryptsetup luksAddKey --key-slot 7 /dev/sdb1 Enter any existing passphrase: ********** Enter new passphrase for key slot: ********** Verify passphrase: ********** Key slot 7 is full, please select another one.
Change passphrase
Change already defined passphrase.
$ sudo cryptsetup luksChangeKey /dev/sdb1 Enter passphrase to be changed: ********** Enter new passphrase: ********** Verify passphrase: **********
Change passphrase in the specified key-slot.
$ sudo cryptsetup luksChangeKey --key-slot 7 /dev/sdb1 Enter passphrase to be changed: ********** Enter new passphrase: ********** Verify passphrase: **********
Remove passphrase
Remove additional passphrase in the specified key slot.
$ sudo cryptsetup luksKillSlot /dev/sdc1 7 Enter any remaining passphrase: **********
Remove already defined passphrase.
$ sudo cryptsetup luksRemoveKey /dev/sdc1 Enter passphrase to be deleted: **********
Additional notes
Create passphrase using characters from 7-bit ASCII to avoid encoding issues.
Always add a backup password or key to access data in case of emergency.
You probably do not take this into account, but the password can be forgotten.
From my own experience, I am confident that this will eventually happen.