man > cryptsetup-luksAddKey(8)

CRYPTSETUP-LUKSADDKEY(8)                Maintenance Commands                CRYPTSETUP-LUKSADDKEY(8)

NAME
       cryptsetup-luksAddKey - add a new passphrase

SYNOPSIS
       cryptsetup luksAddKey [<options>] <device> [<key file with new key>]

DESCRIPTION
       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].

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.

           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.

       --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.

       --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).

       --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.

       --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.

       --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.

       --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).

       --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).

       --token-id
           Specify what token to use when unlocking existing keyslot to get volume key.

       --new-token-id
           Specify what token to use to get the passphrase for a new keyslot.

       --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.

       --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 LUKS2 unbound keyslot.

       --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).

       --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.

EXAMPLES
       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

REPORTING BUGS
       Report bugs at cryptsetup mailing list <cryptsetup AT lists.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/>.

cryptsetup 2.7.0                             2024-11-14                     CRYPTSETUP-LUKSADDKEY(8)