man > cryptsetup-luksFormat(8)

CRYPTSETUP-LUKSFORMAT(8)                Maintenance Commands                CRYPTSETUP-LUKSFORMAT(8)

NAME
       cryptsetup-luksFormat - initialize a LUKS partition and set the initial passphrase

SYNOPSIS
       cryptsetup luksFormat [<options>] <device> [<key file>]

DESCRIPTION
       Initializes a LUKS partition and sets the initial passphrase (for key-slot 0), either via
       prompting or via <key file>. Note that if the second argument is present, then the passphrase
       is taken from the file given there, without the need to use the --key-file option. Also note
       that for both forms of reading the passphrase from a file you can give '-' as file name,
       which results in the passphrase being read from stdin and the safety-question being skipped.

       You cannot call luksFormat on a device or filesystem that is mapped or in use, e.g., mounted
       filesystem, used in LVM, active RAID member, etc. The device or filesystem has to be
       un-mounted in order to call luksFormat.

       To use specific version of LUKS format, use --type luks1 or type luks2. To use OPAL hardware
       encryption on a self-encrypting drive, use --hw-opal or --hw-opal-only.

       <options> can be [--hash, --cipher, --verify-passphrase, --key-size, --key-slot, --key-file
       (takes precedence over optional second argument), --keyfile-offset, --keyfile-size,
       --use-random, --use-urandom, --uuid, --volume-key-file, --iter-time, --header,
       --pbkdf-force-iterations, --force-password, --disable-locks, --timeout, --type, --offset,
       --align-payload (deprecated)].

       For LUKS2, additional <options> can be [--integrity, --integrity-no-wipe, --sector-size,
       --label, --subsystem, --pbkdf, --pbkdf-memory, --pbkdf-parallel, --disable-locks,
       --disable-keyring, --luks2-metadata-size, --luks2-keyslots-size, --keyslot-cipher,
       --keyslot-key-size, --integrity-legacy-padding, --hw-opal, --hw-opal-only].

       WARNING: Doing a luksFormat on an existing LUKS container will make all data in the old
       container permanently irretrievable unless you have a header backup.

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

       --hash, -h <hash-spec>
           Specifies the hash used in the LUKS key setup scheme and volume key digest. The specified
           hash is used for PBKDF2 and AF splitter.

           The hash algorithm must provide at least 160 bits of output. Do not use a non-crypto hash
           like xxhash as this breaks security. Use cryptsetup --help to show the defaults.

       --cipher, -c <cipher-spec>
           Set the cipher specification string.

           cryptsetup --help shows the compiled-in defaults.

           If a hash is part of the cipher specification, then it is used as part of the IV
           generation. For example, ESSIV needs a hash function, while "plain64" does not and hence
           none is specified.

           For XTS mode you can optionally set a key size of 512 bits with the -s option. Key size
           for XTS mode is twice that for other modes for the same security level.

       --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.

           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. 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.

       --use-random, --use-urandom
           For luksFormat these options define which kernel random number generator will be used to
           create the volume key (which is a long-term key).

           See NOTES ON RANDOM NUMBER GENERATORS in cryptsetup(8) for more information. Use
           cryptsetup --help to show the compiled-in default random number generator.

           WARNING: In a low-entropy situation (e.g. in an embedded system) and older kernels, both
           selections are problematic. Using /dev/urandom can lead to weak keys. Using /dev/random
           can block a long time, potentially forever, if not enough entropy can be harvested by the
           kernel.

       --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.

       --offset, -o <number of 512 byte sectors>
           Start offset in the backend device in 512-byte sectors.

           The --offset option sets the data offset (payload) of data device and must be aligned to
           4096-byte sectors (must be multiple of 8). This option cannot be combined with
           --align-payload option.

       --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.

       --progress-frequency seconds
           Print separate line every seconds with wipe progress.

       --progress-json
           Prints progress data in JSON format suitable mostly for machine processing. It prints
           separate line every half second (or based on --progress-frequency value). The JSON output
           looks as follows during progress (except it’s compact single line):

               {
                 "device":"/dev/sda"       // backing device or file
                 "device_bytes":"8192",    // bytes of I/O so far
                 "device_size":"44040192", // total bytes of I/O to go
                 "speed":"126877696",      // calculated speed in bytes per second (based on progress so far)
                 "eta_ms":"2520012"        // estimated time to finish an operation in milliseconds
                 "time_ms":"5561235"       // total time spent in IO operation in milliseconds
               }

           Note on numbers in JSON output: Due to JSON parsers limitations all numbers are
           represented in a string format due to need of full 64bit unsigned integers.

       --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.

       --align-payload <number of 512 byte sectors>
           Align payload at a boundary of value 512-byte sectors.

           If not specified, cryptsetup tries to use the topology info provided by the kernel for
           the underlying device to get the optimal alignment. If not available (or the calculated
           value is a multiple of the default) data is by default aligned to a 1MiB boundary (i.e.
           2048 512-byte sectors).

           For a detached LUKS header, this option specifies the offset on the data device. See also
           the --header option.

           WARNING: This option is DEPRECATED and has often unexpected impact to the data offset and
           keyslot area size (for LUKS2) due to the complex rounding. For fixed data device offset
           use --offset option instead.

       --uuid <UUID>
           Use the provided UUID for the luksFormat command instead of generating a new one. Changes
           the existing UUID when used with the luksUUID command.

           The UUID must be provided in the standard UUID format, e.g.
           12345678-1234-1234-1234-123456789abc.

       --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.

           With a file name as the argument to --header, the file will be automatically created if
           it does not exist. See the cryptsetup FAQ for header size calculation.

           The --align-payload option is taken as absolute sector alignment on ciphertext device and
           can be zero.

       --hw-opal
           Format LUKS2 device with dm-crypt encryption stacked on top HW based encryption
           configured on SED OPAL locking range. This option enables both SW and HW based data
           encryption.

       --hw-opal-only
           Format LUKS2 device with HW based encryption configured on SED OPAL locking range only.
           LUKS2 format only manages locking range unlock key. This option enables HW based data
           encryption managed by SED OPAL drive only.

       --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-blkid
           Disable use of blkid library for checking and wiping on-disk signatures.

       --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).

       --disable-keyring
           Do not load volume key in kernel keyring and store it directly in the dm-crypt target
           instead. This option is supported only for the LUKS2 type.

       --sector-size bytes
           Set sector size for use with disk encryption. It must be power of two and in range 512 -
           4096 bytes. This option is available only with LUKS2 format.

           For LUKS2 devices it’s established based on parameters provided by underlying data
           device. For native 4K block devices it’s 4096 bytes. For 4K/512e (4K physical sector size
           with 512 bytes emulation) it’s 4096 bytes. For drives reporting only 512 bytes block size
           it remains 512 bytes. If data device is regular file put in filesystem it’s 4096 bytes.

           Note that if sector size is higher than underlying device hardware sector and there is
           not integrity protection that uses data journal, using this option can increase risk on
           incomplete sector writes during a power fail.

           If used together with --integrity option and dm-integrity journal, the atomicity of
           writes is guaranteed in all cases (but it cost write performance - data has to be written
           twice).

           Increasing sector size from 512 bytes to 4096 bytes can provide better performance on
           most of the modern storage devices and also with some hw encryption accelerators.

       --label <LABEL> --subsystem <SUBSYSTEM>
           Set label and subsystem description for LUKS2 device. The label and subsystem are
           optional fields and can be later used in udev scripts for triggering user actions once
           the device marked by these labels is detected.

       --integrity <integrity algorithm>
           Specify integrity algorithm to be used for authenticated disk encryption in LUKS2.

           WARNING: This extension is EXPERIMENTAL and requires dm-integrity kernel target
           (available since kernel version 4.12). For native AEAD modes, also enable "User-space
           interface for AEAD cipher algorithms" in "Cryptographic API" section
           (CONFIG_CRYPTO_USER_API_AEAD .config option).

           For more info, see AUTHENTICATED DISK ENCRYPTION section in cryptsetup(8).

       --integrity-legacy-padding
           Use inefficient legacy padding.

           WARNING: Do not use this option until you need compatibility with specific old kernel.

       --luks2-metadata-size <size>
           This option can be used to enlarge the LUKS2 metadata (JSON) area. The size includes 4096
           bytes for binary metadata (usable JSON area is smaller of the binary area). According to
           LUKS2 specification, only these values are valid: 16, 32, 64, 128, 256, 512, 1024, 2048
           and 4096 kB The <size> can be specified with unit suffix (for example 128k).

       --luks2-keyslots-size <size>
           This option can be used to set specific size of the LUKS2 binary keyslot area (key
           material is encrypted there). The value must be aligned to multiple of 4096 bytes with
           maximum size 128MB. The <size> can be specified with unit suffix (for example 128k).

       --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.

       --integrity-no-wipe
           Skip wiping of device authentication (integrity) tags. If you skip this step, sectors
           will report invalid integrity tag until an application write to the sector.

           NOTE: Even some writes to the device can fail if the write is not aligned to page size
           and page-cache initiates read of a sector with invalid integrity tag.

       --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 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-LUKSFORMAT(8)