17.6. Encrypting a blank block device using LUKS2

Procedure

1. Setup a partition as an encrypted LUKS partition:

   # cryptsetup luksFormat /dev/nvme0n1p1
   
   WARNING!
   ========
   This will overwrite data on /dev/nvme0n1p1 irrevocably.
   Are you sure? (Type 'yes' in capital letters): YES
   Enter passphrase for /dev/nvme0n1p1:
   Verify passphrase:

2. Open an encrypted LUKS partition:

   # cryptsetup open /dev/nvme0n1p1 nvme0n1p1_encrypted
   
   Enter passphrase for /dev/nvme0n1p1:

   This unlocks the partition and maps it to a new device by using the device mapper. To not overwrite the encrypted data, this command alerts the kernel that the device is an encrypted device and addressed through LUKS by using the /dev/mapper/device_mapped_name path.

3. Create a file system to write encrypted data to the partition, which must be accessed through the device mapped name:

   # mkfs -t ext4 /dev/mapper/nvme0n1p1_encrypted

4. Mount the device:

   # mount /dev/mapper/nvme0n1p1_encrypted mount-point

Verification

1. Verify if the blank block device is encrypted:

   # cryptsetup luksDump /dev/nvme0n1p1
   
   LUKS header information
   Version:       	2
   Epoch:         	3
   Metadata area: 	16384 [bytes]
   Keyslots area: 	16744448 [bytes]
   UUID:          	34ce4870-ffdf-467c-9a9e-345a53ed8a25
   Label:         	(no label)
   Subsystem:     	(no subsystem)
   Flags:       	(no flags)
   
   Data segments:
     0: crypt
   	offset: 16777216 [bytes]
   	length: (whole device)
   	cipher: aes-xts-plain64
   	sector: 512 [bytes]
   [...]

2. View the status of the encrypted blank block device:

   # cryptsetup status nvme0n1p1_encrypted
   
   /dev/mapper/nvme0n1p1_encrypted is active and is in use.
     type:    LUKS2
     cipher:  aes-xts-plain64
     keysize: 512 bits
     key location: keyring
     device:  /dev/nvme0n1p1
     sector size:  512
     offset:  32768 sectors
     size:    20938752 sectors
     mode:    read/write