CRYPTSETUP-LUKSDUMP(8)	     Maintenance Commands	CRYPTSETUP-LUKSDUMP(8)

NAME
       cryptsetup-luksDump - dump the header information of a LUKS device

SYNOPSIS
       cryptsetup luksDump [<options>] <device>

DESCRIPTION
       Dump the header information of a LUKS device.

       If the --dump-volume-key option is used, the LUKS device volume key is
       dumped instead of the keyslot info.  With the --volume-key-file option,
       the volume key is dumped to a file instead of standard output.  Beware
       that the volume key cannot be changed without reencryption and can be
       used to decrypt the data stored in the LUKS container without a
       passphrase and even without the LUKS header.  This means that if the
       volume key is compromised, the whole device has to be erased or
       reencrypted to prevent further access.  Use this option carefully.

       A passphrase must be supplied to dump the volume key, either
       interactively or via --key-file.

       To dump an unbound key (LUKS2 format only), --unbound parameter,
       specific --key-slot id and proper passphrase must be supplied,
       interactively or via --key-file.	 Optional --volume-key-file parameter
       enables unbound keyslot dump to a file.

       To dump LUKS2 JSON metadata (without basic header information like
       UUID), use the --dump-json-metadata option.

       If --dump-volume-key is used with --key-file and the argument to
       --key-file is '-', no validation question will be asked and no warning
       given.

       <options> can be [--dump-volume-key, --dump-json-metadata, --key-file,
       --keyfile-offset, --keyfile-size, --header, --disable-locks,
       --volume-key-file, --type, --unbound, --key-slot, --timeout,
       --external-tokens-path].

OPTIONS
       --batch-mode, -q
	   Suppresses all confirmation questions.  Use with care!

	   If the --verify-passphrase option is not specified, this option
	   also switches off the passphrase verification.

       --debug or --debug-json
	   Run in debug mode with full diagnostic logs.	 Debug output lines
	   are always prefixed by #.

	   If --debug-json is used, additional LUKS2 JSON data structures are
	   printed.

       --disable-locks
	   Disable lock protection for metadata on disk.  This option is valid
	   only for LUKS2 and is ignored for other formats.

	   WARNING: Do not use this option unless you run cryptsetup in a
	   restricted environment where locking is impossible to perform
	   (where /run directory cannot be used).

       --dump-json-metadata
	   For luksDump (LUKS2 only), this option prints the content of the
	   LUKS2 header JSON metadata area.

       --dump-volume-key, --dump-master-key (OBSOLETE alias)
	   Print the volume key in the displayed information.  Use with care,
	   as the volume key can be used to bypass the passphrases, see also
	   option --volume-key-file.

       --external-tokens-path <absolute path>
	   Override the system directory path where cryptsetup searches for
	   external token handlers (or token plugins).	It must be an absolute
	   path (starting with '/' character).

       --header <device or file storing the LUKS header>
	   Use a detached (separated) metadata device or file where the LUKS
	   header is stored.  This option allows one to store the ciphertext
	   and LUKS header on different devices.

	   For commands that change the LUKS header (e.g., luksAddKey),
	   specify the device or file with the LUKS header directly as the
	   LUKS device.

       --help, -?
	   Show help text and default parameters.

       --key-description text
	   Set the key description in the keyring that will be used for
	   passphrase retrieval.

       --key-file, -d file
	   Read the passphrase from the file.

	   If the name given is "-", then the passphrase will be read from
	   stdin.  In this case, reading will not stop at newline characters.

	   See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8) for
	   more information.

       --keyfile-offset value
	   Skip value bytes at the beginning of the key file.

       --keyfile-size, -l value
	   Read a maximum of value bytes from the key file.  The default is to
	   read the whole file up to the compiled-in maximum that can be
	   queried with --help.	 Supplying more data than the compiled-in
	   maximum aborts the operation.

	   This option is useful to cut trailing newlines, for example.	 If
	   --keyfile-offset is also given, the size count starts after the
	   offset.

       --key-slot, -S <0-N>
	   For LUKS operations that add key material, this option allows you
	   to specify which keyslot is selected for the new key.

	   The maximum number of keyslots depends on the LUKS version.	LUKS1
	   can have up to 8 keyslots.  LUKS2 can have up to 32 keyslots based
	   on keyslot area size and key size, but a valid keyslot ID can
	   always be between 0 and 31 for LUKS2.

       --timeout, -t seconds
	   The number of seconds to wait before a timeout on passphrase input
	   via terminal.  It is relevant every time a passphrase is asked.  It
	   has no effect if used in conjunction with --key-file.

	   This option is useful when the system should not stall if the user
	   does not input a passphrase, e.g., during boot.  The default is a
	   value of 0 seconds, which means to wait forever.

       --type type
	   Specifies required device type, for more info, read the BASIC
	   ACTIONS section in cryptsetup(8).

       --unbound
	   Dumps the existing LUKS2 unbound keyslot.

       --usage
	   Show short option help.

       --version, -V
	   Show the program version.

       --volume-key-file file, --master-key-file file (OBSOLETE alias)
	   Use a volume key stored in a file.

	   The volume key is stored in a file instead of being printed out to
	   standard output.

REPORTING BUGS
       Report bugs at cryptsetup mailing list <cryptsetup@lists.linux.dev> or
       in Issues project section
       <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.

       Please attach the output of the failed command with --debug option
       added.

SEE ALSO
       Cryptsetup FAQ
       <https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>

       cryptsetup(8), integritysetup(8) and veritysetup(8)

CRYPTSETUP
       Part of cryptsetup project <https://gitlab.com/cryptsetup/cryptsetup/>.

cryptsetup 2.8.1		  2025-08-13		CRYPTSETUP-LUKSDUMP(8)