How do I add a key file to Luks Cryptsetup?

Posted on by Emilia Duggan

How do I add a key file to Luks Cryptsetup?

Adding a key file to an existing LUKS volume:

  1. Prepare a key file, whether it is random data or something specific. Examples:
  2. Add the key file to the encrypted device with the command: cryptsetup luksAddKey DEV /PATH/TO/KEYFILE.
  3. If DEV needs to be auto-unlocked at boot time, /etc/crypttab must be edited.

How do you add a Luks passphrase?

1 Answer

  1. Add a new password slot: sudo cryptsetup luksAddKey /dev/sda3.
  2. Remove a password slot:
  3. See how many slots are active: sudo cryptsetup luksDump /dev/sda3.
  4. Test if a password is valid for the partition:
  5. Backup the header of a luks partition:
  6. List all encrypted file systems:

How do I get Luks key?

  1. Step 1 – Creating a key file with random characters. WARNING!
  2. Step 2 – Stuff random data to the device.
  3. Step 3 – Format device (hard drive)
  4. Step 3 – Open the device.
  5. Step 4 – Format the device.
  6. Step 5 – Mount the device.
  7. Step 6 – Persistent (permanent) LUKS mounting at boot time using a key file.
  8. Step 7 – Closing the device.

Where are Luks keys stored?

LUKS keys are used to access the real encryption key. They are stored in slots in the header of the (encrypted) partition, disk or file.

What does Luks stand for?

Linux Unified Key Setup
According to Wikipedia, the Linux Unified Key Setup (LUKS) is a disk encryption specification created by Clemens Fruhwirth in 2004 and was originally intended for Linux.

What is LUKS2?

LUKS2 is the second version of the Linux Unified Key Setup for disk encryp- tion management. It is the follow-up of the LUKS1 [1, 2] format that extends capabilities of the on-disk format and removes some known problems and lim- itations.

Can I change LUKS password?

Changing the password on a LUKS drive with only one password is easy: Open Terminal and run the following command by replacing the current location of the drive with “sdX”. Then enter the existing password to create a new one. LUKS drives can actually have multiple passwords or key files, even up to eight.

Why does cryptsetup stop when there is insufficient key material?

If there is insufficient key material in the key file, cryptsetup will quit with an error. Password processing is totally different for LUKS. LUKS uses PBKDF2 to protect against dictionary attacks (see RFC 2898).

How does cryptsetup work?

Cryptsetup is usually used directly on a block device (disk partition or LVM volume). However, if the device argument is a file, cryptsetup tries to allocate a loopback device and map it into this file.

How do I use DM-cryptsetup?

cryptsetup is used to conveniently setup dm-crypt managed device-mapper mappings. For basic (plain) dm-crypt mappings, there are four operations. creates a mapping with backed by device . can be [–hash, –cipher, –verify-passphrase, –key-file, –key-size, –offset, –skip, –readonly]

How to find encrypted Luks key in dmsetup?

The following dmsetup table –showkeys will show the encrypted keys of all the partitions that are mounted on your system. The field after “aes-cbc-essiv:sha256” is the encrypted password. Get the encrypted LUKS key and store it in a file.