cryptsetup-luksDump(8) — Linux manual page



NAME         top

       cryptsetup-luksDump - dump the header information of a LUKS

SYNOPSIS         top

       cryptsetup luksDump [<options>] <device>

DESCRIPTION         top

       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. Together with the
       --volume-key-file option, 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.

       To dump the volume key, a passphrase has to be supplied, either
       interactively or via --key-file.

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

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

       <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].

       WARNING: 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         top

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

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

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

           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.

       --volume-key-file, --master-key-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.

           For luksDump (LUKS2 only) this option prints content of 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.

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

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

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

           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.

       --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
           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.

           Disable lock protection for metadata on disk. This option is
           valid only for LUKS2 and 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).

           Dumps existing LUKS2 unbound keyslot.

       --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.

       --version, -V
           Show the program version.

           Show short option help.

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

REPORTING BUGS         top

       Report bugs at cryptsetup mailing list
       <> or in Issues project section

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

SEE ALSO         top

       Cryptsetup FAQ

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

CRYPTSETUP         top

       Part of cryptsetup project
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cryptsetup 2.6.1-git           2022-12-14         CRYPTSETUP-LUKSDUMP(8)

Pages that refer to this page: cryptsetup(8)cryptsetup-benchmark(8)cryptsetup-luksAddKey(8)cryptsetup-luksChangeKey(8)cryptsetup-luksConvertKey(8)cryptsetup-luksFormat(8)cryptsetup-reencrypt(8)