Provided by: cryptsetup-bin_2.5.0-2ubuntu1_amd64 
NAME
cryptsetup-luksAddKey - add a new passphrase
SYNOPSIS
cryptsetup luksAddKey [<options>] <device> [<key file with new key>]
DESCRIPTION
Adds a new passphrase. An existing passphrase must be supplied interactively or via
--key-file. The new passphrase to be added can be specified interactively or read from the
file given as the positional argument.
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-offset,
--new-keyfile-size, --key-slot, --volume-key-file, --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, --verify-passphrase].
OPTIONS
--type <device-type>
Specifies required device type, for more info read BASIC ACTIONS section in
cryptsetup(8).
--hash, -h <hash-spec>
The specified hash is used for PBKDF2 and AF splitter.
--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.
--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.
With LUKS, the passphrase supplied via --key-file is always the existing passphrase
requested by a command, except in the case of luksFormat where --key-file is
equivalent to the positional key file argument.
If you want to set a new passphrase via key file, you have to use a positional
argument to luksAddKey.
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.
--new-keyfile-offset value
Skip value bytes at the start when adding a new passphrase from key file with
luksAddKey.
--new-keyfile-size value
Read a maximum of value bytes when adding a new passphrase from key file with
luksAddKey. 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.
--volume-key-file, --master-key-file (OBSOLETE alias)
Use a volume key stored in a file. For luksAddKey this allows adding a new passphrase
without having to know an existing one.
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.
--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.
--key-size, -s bits
Sets key size in bits. The argument has to be a multiple of 8. The possible key-sizes
are limited by the cipher and mode used.
See /proc/crypto for more information. Note that key-size in /proc/crypto is stated in
bytes.
This option can be used for open --type plain or luksFormat. All other LUKS actions
will use the key-size specified in the LUKS header. Use cryptsetup --help to show the
compiled-in defaults.
--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. 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).
--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.
--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.
--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.
--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.
--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.
--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).
--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).
--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.
--unbound
Creates new or 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.
--usage
Show short option help.
--help, -?
Show help text and default parameters.
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 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/>.