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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | REPORTING BUGS | SEE ALSO | CRYPTSETUP |
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CRYPTSETUP-LUKSADDKEY(8) Maintenance Commands CRYPTSETUP-LUKSADDKEY(8)
cryptsetup-luksAddKey - add a new passphrase
cryptsetup luksAddKey [<options>] <device> [<key file with new
key>]
Adds a keyslot protected by a new passphrase. An existing
passphrase must be supplied interactively, via --key-file or
LUKS2 token (plugin). Alternatively to existing passphrase user
may pass directly volume key (via --volume-key-file or
--volume-key-keyring). The new passphrase to be added can be
specified interactively, read from the file given as the
positional argument (also via --new-keyfile parameter) or via
LUKS2 token.
NOTE: with --unbound option the action creates new unbound LUKS2
keyslot. The keyslot cannot be used for device activation. If you
don’t pass new key via --volume-key-file option, new random key
is generated. Existing passphrase for any active keyslot is not
required.
NOTE: some parameters are effective only if used with LUKS2
format that supports per-keyslot parameters. For LUKS1, PBKDF
type and hash algorithm is always the same for all keyslots.
<options> can be [--key-file, --keyfile-offset, --keyfile-size,
--new-keyfile, --new-keyfile-offset, --new-keyfile-size,
--key-slot, --new-key-slot, --volume-key-file,
--volume-key-keyring, --force-password, --hash, --header,
--disable-locks, --iter-time, --pbkdf, --pbkdf-force-iterations,
--pbkdf-memory, --pbkdf-parallel, --unbound, --type,
--keyslot-cipher, --keyslot-key-size, --key-size, --timeout,
--token-id, --token-type, --token-only, --new-token-id,
--verify-passphrase, --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 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).
--external-tokens-path absolute_path
Override system directory path where cryptsetup searches for
external token handlers (or token plugins). It must be
absolute path (starting with '/' character).
--force-password
Do not use password quality checking for new LUKS passwords.
This option is ignored if cryptsetup is built without
password quality checking support.
For more info about password quality check, see the manual
page for pwquality.conf(5) and passwdqc.conf(5).
--hash, -h <hash-spec>
The specified hash is used for PBKDF2 and AF splitter.
--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.
--help, -?
Show help text and default parameters.
--iter-time, -i <number of milliseconds>
The number of milliseconds to spend with PBKDF passphrase
processing. Specifying 0 as parameter selects the compiled-in
default.
--key-description <text>
Set key description in keyring that will be used for
passphrase retrieval.
--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
characters.
The passphrase supplied via --key-file is always the
passphrase for existing keyslot requested by the command.
If you want to set a new passphrase via key file, you have to
use a positional argument or parameter --new-keyfile.
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-size, -s bits
Provide volume key size in bits. The argument has to be a
multiple of 8.
This option is required when parameter --volume-key-file is
used to provide current volume key. Also, it is used when new
unbound keyslot is created by specifying --unbound parameter.
--key-slot, -S <0-N>
When used together with parameter --new-key-slot this option
allows you to specify which key slot is selected for
unlocking volume key.
NOTE: This option is ignored if existing volume key gets
unlocked via LUKS2 token (--token-id, --token-type or
--token-only parameters) or when volume key is provided
directly via --volume-key-file parameter.
NOTE: To maintain backward compatibility, without
--new-key-slot parameter, 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.
--keyslot-cipher <cipher-spec>
This option can be used to set specific cipher encryption for
the LUKS2 keyslot area.
--keyslot-key-size <bits>
This option can be used to set specific key size for the
LUKS2 keyslot area.
--new-keyfile name
Read the passphrase for a new keyslot from file.
If the name given is "-", then the passphrase will be read
from stdin. In this case, reading will not stop at newline
characters.
This is alternative method to positional argument when adding
new passphrase via kefile.
--new-keyfile-offset value
Skip value bytes at the start when adding a new passphrase
from key file.
--new-keyfile-size value
Read a maximum of value bytes when adding a new passphrase
from key file. The default is to read the whole file up to
the compiled-in maximum length that can be queried with
--help. Supplying more than the compiled in maximum aborts
the operation. When --new-keyfile-offset is also given,
reading starts after the offset.
--new-key-description <text>
Set key description in keyring that will be used for new
passphrase retrieval.
--new-key-slot <0-N>
This option allows you to specify which key slot is selected
for the new key.
NOTE: When used this option affects --key-slot option.
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.
--new-token-id
Specify what token to use to get the passphrase for a new
keyslot.
--pbkdf <PBKDF spec>
Set Password-Based Key Derivation Function (PBKDF) algorithm
for LUKS keyslot. The PBKDF can be: pbkdf2 (for PBKDF2
according to RFC2898), argon2i for Argon2i or argon2id for
Argon2id (see Argon2
<https://www.cryptolux.org/index.php/Argon2> for more info).
For LUKS1, only PBKDF2 is accepted (no need to use this
option). The default PBKDF for LUKS2 is set during
compilation time and is available in cryptsetup --help
output.
A PBKDF is used for increasing dictionary and brute-force
attack cost for keyslot passwords. The parameters can be
time, memory and parallel cost.
For PBKDF2, only time cost (number of iterations) applies.
For Argon2i/id, there is also memory cost (memory required
during the process of key derivation) and parallel cost
(number of threads that run in parallel during the key
derivation.
Note that increasing memory cost also increases time, so the
final parameter values are measured by a benchmark. The
benchmark tries to find iteration time (--iter-time) with
required memory cost --pbkdf-memory. If it is not possible,
the memory cost is decreased as well. The parallel cost
--pbkdf-parallel is constant and is checked against available
CPU cores.
You can see all PBKDF parameters for particular LUKS2 keyslot
with cryptsetup-luksDump(8) command.
NOTE: If you do not want to use benchmark and want to specify
all parameters directly, use --pbkdf-force-iterations with
--pbkdf-memory and --pbkdf-parallel. This will override the
values without benchmarking. Note it can cause extremely long
unlocking time or cause out-of-memory conditions with
unconditional process termination. Use only in specific
cases, for example, if you know that the formatted device
will be used on some small embedded system.
MINIMAL AND MAXIMAL PBKDF COSTS: For PBKDF2, the minimum
iteration count is 1000 and maximum is 4294967295 (maximum
for 32bit unsigned integer). Memory and parallel costs are
unused for PBKDF2. For Argon2i and Argon2id, minimum
iteration count (CPU cost) is 4 and maximum is 4294967295
(maximum for 32bit unsigned integer). Minimum memory cost is
32 KiB and maximum is 4 GiB. (Limited by addressable memory
on some CPU platforms.) If the memory cost parameter is
benchmarked (not specified by a parameter) it is always in
range from 64 MiB to 1 GiB. The parallel cost minimum is 1
and maximum 4 (if enough CPUs cores are available, otherwise
it is decreased).
--pbkdf-force-iterations <num>
Avoid PBKDF benchmark and set time cost (iterations)
directly. It can be used for LUKS/LUKS2 device only. See
--pbkdf option for more info.
--pbkdf-memory <number>
Set the memory cost for PBKDF (for Argon2i/id the number
represents kilobytes). Note that it is maximal value, PBKDF
benchmark or available physical memory can decrease it. This
option is not available for PBKDF2.
--pbkdf-parallel <number>
Set the parallel cost for PBKDF (number of threads, up to 4).
Note that it is maximal value, it is decreased automatically
if CPU online count is lower. This option is not available
for PBKDF2.
--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
--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.
--token-id
Specify what token to use when unlocking existing keyslot to
get volume key.
--token-only
Use only LUKS2 tokens to unlock existing volume key.
NOTE: To create a new keyslot using passphrase provided by a
token use --new-token-id parameter.
--token-type type
Specify what token type (all type tokens) to use when
unlocking existing keyslot to get volume key.
--type <device-type>
Specifies required device type, for more info read BASIC
ACTIONS section in cryptsetup(8).
--unbound
Creates new LUKS2 unbound keyslot.
--usage
Show short option help.
--verify-passphrase, -y
When interactively asking for a passphrase, ask for it twice
and complain if both inputs do not match. Ignored on input
from file or stdin.
--version, -V
Show the program version.
--volume-key-file, --master-key-file (OBSOLETE alias)
Use a volume key stored in a file. This allows adding a new
keyslot without having to know passphrase to existing one. It
may be also used when no keyslot is active.
WARNING: If you create your own volume key, you need to make
sure to do it right. Otherwise, you can end up with a
low-entropy or otherwise partially predictable volume key
which will compromise security.
--volume-key-keyring <key description>
Use a volume key stored in a keyring. This allows one to open
luks and device types without giving a passphrase. The key
and associated type has to be readable from userspace so that
volume key digest may be verified in before activation.
The <key description> uses keyctl-compatible syntax. This can
either be a numeric key ID or a string name in the format
%<key type>:<key name>. See also KEY IDENTIFIERS section of
keyctl(1). When no %<key type>: prefix is specified we assume
the key type is user (default type).
NOTE: When not specified otherwise interactive passphrase prompt
is always default method.
Add new keyslot using interactive passphrase prompt for both
existing and new passphrase:
cryptsetup luksAddKey /dev/device
Add new keyslot using LUKS2 tokens to unlock existing keyslot
with interactive passphrase prompt for new passphrase:
cryptsetup luksAddKey --token-only /dev/device
Add new keyslot using LUKS2 systemd-tpm2 tokens to unlock
existing keyslot with interactive passphrase prompt for new
passphrase (systemd-tpm2 token plugin must be available):
cryptsetup luksAddKey --token-type systemd-tpm2 /dev/device
Add new keyslot using interactive passphrase prompt for existing
keyslot, reading new passphrase from key_file:
cryptsetup luksAddKey --new-keyfile key_file /dev/device or
cryptsetup luksAddKey /dev/device key_file
Add new keyslot using volume stored in volume_key_file and LUKS2
token in slot 5 to get new keyslot passphrase (token in slot 5
must exist and respective token plugin must be available):
cryptsetup luksAddKey --volume-key-file volume_key_file
--new-token-id 5 /dev/device
Report bugs at cryptsetup mailing list
<cryptsetup@lists.linux.dev> or in Issues project section
<https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.
Please attach 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 dm-crypt@saout.de. This
page was obtained from the project's upstream Git repository
⟨https://gitlab.com/cryptsetup/cryptsetup.git⟩ on 2024-06-14. (At
that time, the date of the most recent commit that was found in
the repository was 2024-06-11.) 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
man-pages@man7.org
cryptsetup 2.8.0-git 2023-12-22 CRYPTSETUP-LUKSADDKEY(8)
Pages that refer to this page: cryptsetup(8)
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HTML rendering created 2024-06-26 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. |
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