|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | REPORTING BUGS | SEE ALSO | CRYPTSETUP |
|
|
|
CRYPTSETUP-LUKSDUMP(8) Maintenance Commands CRYPTSETUP-LUKSDUMP(8)
cryptsetup-luksDump - dump the header information of a LUKS device
cryptsetup luksDump [<options>] <device>
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].
--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.
Report bugs at cryptsetup mailing list
<[email protected]> or in Issues project section
<https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.
Please attach the output of the failed command with --debug option
added.
Cryptsetup FAQ
<https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>
cryptsetup(8), integritysetup(8) and veritysetup(8)
Part of cryptsetup project
<https://gitlab.com/cryptsetup/cryptsetup/>. This page is part of
the Cryptsetup ((open-source disk encryption)) project.
Information about the project can be found at
⟨https://gitlab.com/cryptsetup/cryptsetup⟩. If you have a bug
report for this manual page, send it to [email protected]. This
page was obtained from the project's upstream Git repository
⟨https://gitlab.com/cryptsetup/cryptsetup.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-01.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
cryptsetup 2.8.1-git 2025-08-09 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)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|