LUKS
Contents
Backup Header
cryptsetup luksHeaderBackup <luks device> --header-backup-file <header backup file>
Dump Header
cryptsetup luksDump <luks device/header backup file>
Test Passphrase
cryptsetup luksOpen --test-passphrase <luks device/header backup file>
Extract Master Key
cryptsetup luksDump --dump-master-key <luks device/header backup file>
Save it to a file:
echo "masterkey" | xxd -r -p > <master key file>
Recover with Master Key
Open the LUKS device:
cryptsetup luksOpen --master-key-file=<master key file> <luks device> <decrypted block device>
Add a new passphrase:
cryptsetup luksAddKey --master-key-file=<master key file> <luks device>