# cryptsetup-luksFormat

## 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 passphrase via prompting
           or <key file>. Note that if the second argument is present, the
           passphrase is taken from the file given there, without using the
           --key-file option. Also note that for both forms of reading the
           passphrase from a file, you can give '-' as a 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., a mounted filesystem, used in LVM, active
           RAID member, etc. The device or filesystem has to be unmounted in
           order to call luksFormat.
    
           To enforce a specific version of LUKS format, use _--type luks1_ or
           _type luks2_. The default format is LUKS2.
    
           To use hardware encryption on an OPAL self-encrypting drive, use
           --hw-opal or --hw-opal-only. Note that some OPAL drives can
           require a PSID reset (with deletion of data) before using the LUKS
           format with OPAL options. See --hw-opal-factory-reset option in
           cryptsetup _erase_ command.
    
           Doing a luksFormat on an existing LUKS container will regenerate
           the volume key. Unless you have a header backup, all old encrypted
           data in the container will be permanently irretrievable. Note that
           luksFormat does not wipe or overwrite the data area. It only
           creates a new LUKS header with fresh keyslots. See cryptsetup FAQ
           for more info on how to wipe the whole device, including encrypted
           data.
    
           **< 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].
    


## OPTIONS



           **--align-payload** _< number of 512 byte sectors>_ (DEPRECATED, use
           --offset)
               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.
    
               This option is DEPRECATED and has an unexpected impact on the
               data offset and keyslot area size (for LUKS2) due to the
               complex rounding. For fixed data device offset, use --offset
               option instead.
    
           **--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.
    
           **--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.
    
           **--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-blkid**
               Disable use of the blkid library for checking and wiping
               on-disk signatures.
    
           **--disable-keyring**
               Do not load the volume key in the kernel keyring; store it
               directly in the dm-crypt target instead. This option is
               supported only for the LUKS2 type.
    
           **--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).
    
           **--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>_
               Specifies the hash used in the LUKS key setup scheme and
               volume key digest. The specified hash is used for PBKDF2 and
               the 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.
    
           **--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.
    
               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 the ciphertext device and can be zero.
    
           **--help** , **-?**
               Show help text and default parameters.
    
           **--hw-opal**
               Format LUKS2 device with dm-crypt encryption stacked on top of
               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 the locking
               range unlock key. This option enables HW-based data encryption
               managed by the SED OPAL drive only.
    
               Please note that with OPAL-only (--hw-opal-only) encryption,
               the configured OPAL administrator PIN (passphrase) allows
               unlocking all configured locking ranges without LUKS keyslot
               decryption (without knowledge of LUKS passphrase). Because of
               many observed problems with compatibility, cryptsetup
               currently DOES NOT use OPAL single-user mode, which would
               allow such decoupling of OPAL admin PIN access.
    
           **--integrity** _< integrity algorithm>_
               Specify the integrity algorithm to be used for authenticated
               disk encryption in LUKS2.
    
               **WARNING: This extension is EXPERIMENTAL** and requires
               dm-integrity kernel target. For native AEAD modes, also enable
               "User-space interface for AEAD cipher algorithms" in the
               "Cryptographic API" section (CONFIG_CRYPTO_USER_API_AEAD
               .config option).
    
               For more info, see the _AUTHENTICATED DISK ENCRYPTION_ section
               in cryptsetup(8).
    
           **--integrity-inline**
               Store integrity tags in hardware sector integrity fields. The
               device must support sectors with additional protection
               information (PI, also known as DIF - data integrity field) of
               the requested size. Another storage subsystem must not use the
               additional field (the device must present a "nop" profile in
               the kernel). Note that some devices must be reformatted at a
               low level to support this option; for NVMe devices, see
               nvme(1) id-ns LBA profiles.
    
               No journal or bitmap is used in this mode. The device should
               operate with native speed (without any overhead). This option
               is available since the Linux kernel version 6.11.
    
           **--integrity-key-size** _bytes_
               The size of the data integrity key. Configurable only for HMAC
               integrity. The default integrity key size is set to the same
               as the hash output length.
    
           **--integrity-legacy-padding**
               Use inefficient legacy padding.
    
               Do not use this option until you need compatibility with a
               specific old kernel.
    
           **--integrity-no-wipe**
               Skip wiping of device authentication (integrity) tags. If you
               skip this step, sectors will report an invalid integrity tag
               until an application writes to the sector.
    
               Skipping this step could also cause write failures due to IO
               operation alignments. For example, kernel page cache can
               request a read of a full page that fails due to an
               uninitialized integrity tag. It is usually a bug in the
               application that tries to read data that was not written
               before.
    
           **--iter-time** , **-i** _< number of milliseconds>_
               The number of milliseconds to spend with PBKDF passphrase
               processing. Specifying 0 as a parameter selects the
               compiled-in default.
    
           **--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-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 the 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.
    
           **--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.
    
           **--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 a specific key size for the
               LUKS2 keyslot area.
    
           **--label** _< label>_,  **--subsystem** _< subsystem>_
               Set label and subsystem description for LUKS2 device. These
               are similar to filesystem labels. The label and subsystem are
               optional fields and can be later used in udev scripts to
               trigger user actions once the device marked by these labels is
               detected.
    
           **--luks2-keyslots-size** _size_
               This option can be used to set a specific size of the LUKS2
               binary keyslot area (key material is encrypted there). The
               value must be aligned to a multiple of 4096 bytes with a
               maximum size 128MB. The <size> can be specified with a unit
               suffix (for example, 128k).
    
           **--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 the
               LUKS2 specification, only these values are valid: 16, 32, 64,
               128, 256, 512, 1024, 2048 and 4096 kB. The <size> can be
               specified with a unit suffix (for example, 128k).
    
           **--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 the data
               device and must be aligned to 4096-byte sectors (must be a
               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 the _cryptsetup --help_ output.
    
               A PBKDF is used for increasing the dictionary and brute-force
               attack cost for keyslot passwords. The parameters can be time,
               memory and parallel cost.
    
               For PBKDF2, only the 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 a particular LUKS2
               keyslot with the cryptsetup-luksDump(8) command.
    
               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 the maximum is 4294967295 (maximum
               for 32-bit unsigned integer). Memory and parallel costs are
               not supported for PBKDF2. For **Argon2i** and **Argon2id** , the
               minimum iteration count (CPU cost) is 4, and the maximum is
               4294967295 (maximum for a 32-bit unsigned integer). Minimum
               memory cost is 32 KiB and maximum is 4 GiB. If the memory cost
               parameter is benchmarked (not specified by a parameter), it is
               always in the range from 64 MiB to 1 GiB. Memory cost above
               1GiB (up to the 4GiB maximum) can be setup only by the
               --pbkdf-memory parameter. The parallel cost minimum is 1 and
               maximum 4 (if enough CPU cores are available, otherwise it is
               decreased by the available CPU cores).
    
               **WARNING:** Increasing PBKDF computational costs above the
               mentioned limits provides negligible additional security
               improvement. While elevated costs significantly increase
               brute-force overhead, they offer negligible protection against
               dictionary attacks. The marginal cost increase for processing
               an entire dictionary remains fundamentally insufficient.
    
               The hardcoded PBKDF limits represent engineered trade-offs
               between cryptographic security and operational usability. LUKS
               maintains portability and must be used within a reasonable
               time on resource-constrained systems.
    
               Cryptsetup deliberately restricts maximum memory cost (4 GiB)
               and parallel cost (4) parameters due to architectural
               limitations (like embedded and legacy systems).
    
               PBKDF memory cost mandates actual physical RAM allocation with
               intensive write operations that must remain in physical RAM.
               Any swap usage results in unacceptable performance
               degradation. Memory management often overcommits allocations
               beyond available physical memory, expecting most allocated
               memory to remain unused. In such situations, as PBKDF always
               uses all allocated memory, it frequently causes out-of-memory
               failures that abort cryptsetup operations.
    
           **--pbkdf-force-iterations** _number_
               Avoid the PBKDF benchmark and set the time cost (iterations)
               directly. It can be used only for a LUKS/LUKS2 device. 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 the 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 the maximal value; it is decreased
               automatically if the CPU online count is lower. This option is
               not available for PBKDF2.
    
           **--progress-frequency** _seconds_
               Print a separate line every _seconds_ with wipe progress.
    
           **--progress-json**
               Prints progress data in JSON format, which is suitable mostly
               for machine processing. It prints a separate line every half
               second (or based on --progress-frequency value). The JSON
               output looks as follows during progress (except it’s a 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 parser
               limitations, all numbers are represented in a string format
               due to the need for full 64-bit unsigned integers.
    
           **--sector-size** _bytes_
               Set encryption sector size for use with _LUKS2_ device type. It
               must be a power of two and in the 512 - 4096 bytes range.
    
               The encryption sector size is set based on the underlying data
               device if not specified explicitly. For native 4096-byte
               physical sector devices, it is set to 4096 bytes. For
               4096/512e (4096-byte physical sector size with 512-byte sector
               emulation), it is set to 4096 bytes. For drives reporting only
               a 512-byte physical sector size, it is set to 512 bytes. If
               the data device is a regular file (container), it is set to
               4096 bytes.
    
               If used together with the --integrity option and dm-integrity
               journal, the atomicity of writes is guaranteed in all cases
               (but it costs write performance - data has to be written
               twice).
    
               Increasing sector size from 512 to 4096 bytes can provide
               better performance on most modern storage devices and with
               some hardware encryption accelerators.
    
               Note that using a sector size larger than the underlying
               storage device’s physical sector size may result in data
               corruption during unexpected power failures. A power failure
               during write operations may result in only partial completion
               of the encryption sector write, leaving encrypted data in an
               inconsistent state that cannot be properly decrypted.
    
           **--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).
    
           **--usage**
               Show short option help.
    
           **--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).
    
               Do not use these options with recent kernels (later than
               version 5.6). For more details, see **NOTES ON RANDOM NUMBER**
               **GENERATORS** in cryptsetup(8) and urandom(4).
    
           **--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.
    
           **--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** _file_ , --master-key-file 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.
    


## CRYPTSETUP



           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 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
           man-pages@man7.org
    
    cryptsetup 2.8.1-git            2025-08-09       _CRYPTSETUP-LUKSFORMAT_(8)
    


* * *