--align-payload<numberof512bytesectors>
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.
--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.
--block-sizevalue(LUKS1only)
Use re-encryption block size of value in MiB.
Values can be between 1 and 64 MiB.
--cipher,-c<cipher-spec>LUKS2: Set the cipher specification string for data segment only.
LUKS1: Set the cipher specification string for data segment and keyslots.
NOTE: In encrypt mode, if cipher specification is omitted the default cipher is applied. In reencrypt
mode, if no new cipher specification is requested, the existing cipher will remain in use. Unless the
existing cipher was "cipher_null". In that case default cipher would be applied as in encrypt mode.
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.
--debugor--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.
--decrypt
Initialize (and run) device decryption mode.
--device-sizesize[units]
Instead of real device size, use specified value. It means that only specified area (from the start
of the device to the specified size) will be reencrypted.
LUKS2: When used together with --reduce-device-size, only the initial size value (--device-size
parameter) of data is shifted backwards while being encrypted.
NOTE: The sum of --device-size and --reduce-device-size values must not exceed real device size.
WARNING: This is destructive operation. Data beyond --device-size limit may be lost after operation
gets finished.
If no unit suffix is specified, the size is in bytes.
Unit suffix can be S for 512 byte sectors, K/M/G/T (or KiB,MiB,GiB,TiB) for units with 1024 base or
KB/MB/GB/TB for 1000 base (SI scale).
--disable-blkid
Disable use of blkid library for checking and wiping on-disk signatures.
--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.
--disable-locks
Disable lock protection for metadata on disk. This option is valid only for LUKS2 and ignored for
other formats.
NOTE: With locking disabled LUKS2 images in files can be fully (re)encrypted offline without need for
super user privileges provided used block ciphers are available in crypto backend.
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).
--encrypt,--new,-N
Initialize (and run) device in-place encryption mode.
--force-no-keyslots(LUKS2only)
Enforce initialization of reencryption operation with additional --volume-key-file,
--new-volume-key-file, --volume-key-keyring or --new-volume-key-keyring parameters that would result
in deletion of all remaining LUKS2 keyslots containing volume key.
NOTE: LUKS2 keyslot with new volume key may be added after the reencryption operation is finished.
See cryptsetup-luksAddKey(8) command.
WARNING: Use with extreme caution! If you loose volume key stored in a file or in a kernel keyring
before adding LUKS2 keyslot containing new volume key the device will become unusable and all data
will be lost.
--force-offline-reencrypt(LUKS2only)
Bypass active device auto-detection and enforce offline reencryption.
This option is useful especially for reencryption of LUKS2 images put in files (auto-detection is not
reliable in this scenario).
It may also help in case active device auto-detection on particular data device does not work or
report errors.
WARNING: Use with extreme caution! This may destroy data if the device is activated and/or actively
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>LUKS1: Specifies the hash used in the LUKS1 key setup scheme and volume key digest.
NOTE: if this parameter is not specified, default hash algorithm is always used for new LUKS1 device
header.
LUKS2: Ignored unless new keyslot pbkdf algorithm is set to PBKDF2 (see --pbkdf).
--header<deviceorfilestoringtheLUKSheader>
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.
If used with --encrypt/--new option, the header file will be created (or overwritten). Use with care.
LUKS2: For decryption mode the option may be used to export original LUKS2 header to a detached file.
The passed future file must not exist at the time of initializing the decryption operation. This
frees space in head of data device so that data can be moved at original LUKS2 header location. Later
on decryption operation continues as if the ordinary detached header was passed.
WARNING: Never put exported header file in a filesystem on top of device you are about to decrypt! It
would cause a deadlock.
--help,-?
Show help text and default parameters.
--hotzone-sizesize(LUKS2only)
This option can be used to set an upper limit on the size of reencryption area (hotzone). The size
can be specified with unit suffix (for example 50M). Note that actual hotzone size may be less than
specified <size> due to other limitations (free space in keyslots area or available memory).
With decryption mode for devices with LUKS2 header placed in head of data device, the option
specifies how large is the first data segment moved from original data offset pointer.
--init-only(LUKS2only)
Initialize reencryption (any mode) operation in LUKS2 metadata only and exit. If any reencrypt
operation is already initialized in metadata, the command with --init-only parameter fails.
--iter-time,-i<numberofmilliseconds>
The number of milliseconds to spend with PBKDF passphrase processing for the new LUKS header.
--keep-keyLUKS2: Do not change effective volume key and change other parameters provided it is requested.
LUKS1: Reencrypt only the LUKS1 header and keyslots. Skips data in-place reencryption.
--key-file,-dname
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.
WARNING: --key-file option can be used only if there is only one active keyslot, or alternatively,
also if --key-slot option is specified (then all other keyslots will be disabled in new LUKS device).
If this option is not used, cryptsetup will ask for all active keyslot passphrases.
--keyfile-offsetvalue
Skip value bytes at the beginning of the key file.
--keyfile-size,-lvalue
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,-sbitsLUKS2: Provide current key size in bits. The argument has to be a multiple of 8. Useful when
specifying the size of current volume key when no keyslot is active.
LUKS1: See --new-key-size.
--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.
For reencryption mode it selects specific keyslot (and passphrase) that can be used to unlock new
volume key. If used all other keyslots get removed after reencryption operation is finished.
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.
--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.
--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).
--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).
--new-key-sizebits
Sets new key size in bits. The argument has to be a multiple of 8. The possible key-sizes are limited
by the new cipher and mode used in reencryption.
See /proc/crypto for more information. Note that key-size in /proc/crypto is stated in bytes.
LUKS1: If you are increasing key size, there must be enough space in the LUKS header for enlarged
keyslots (data offset must be large enough) or reencryption cannot be performed.
If there is not enough space for keyslots with new key size, you can destructively shrink device with
--reduce-device-size option.
--new-volume-key-file
Use (set) new volume key stored in a file. The option must be paired with --new-key-size parameter
when initializing reencryption operation.
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.
--new-volume-key-keyring<keydescription>
Use (set) new volume key stored in a keyring.
The size of key stored in a keyring must be compatible with new cipher used in reencryption
operation. See /proc/crypto for more information. Note that key-size in /proc/crypto is stated in
bytes.
The <keydescription> uses keyctl-compatible syntax. This can either be a numeric key ID or a string
name in the format %<keytype>:<keyname>. See also KEYIDENTIFIERS section of keyctl(1). When no
%<keytype>: prefix is specified we assume the key type is user (default type).
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.
--offset,-o<numberof512bytesectors>
Start offset in the backend device in 512-byte sectors. This option is only relevant for the encrypt
mode.
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<PBKDFspec>
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.
MINIMALANDMAXIMALPBKDFCOSTS: 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.
--progress-frequencyseconds
Print separate line every seconds with reencryption 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.
--reduce-device-sizesize
This means that last size sectors on the original device will be lost, data will be effectively
shifted by specified number of sectors.
It could be useful if you added some space to underlying partition or logical volume (so last size
sectors contains no data).
For units suffix see --device-size parameter description.
WARNING: This is a destructive operation and cannot be reverted. Use with extreme care - accidentally
overwritten filesystems are usually unrecoverable.
LUKS2: Initialize LUKS2 reencryption with data device size reduction (currently only encryption mode
is supported). The last size sectors on the original plaintext device is used for temporarily storing
original first data segment. The former first data segment is replaced with LUKS2 header (half the
size value) and plaintext data are shifted backwards ( again half the size value) while being
encrypted.
Recommended minimal size is twice the default LUKS2 header size (--reduce-device-size 32M) for
encryption mode.
NOTE: The sum of --device-size and --reduce-device-size values must not exceed real device size.
LUKS1: Enlarge data offset to specified value by shrinking device size.
You cannot shrink device more than by 64 MiB (131072 sectors).
--resiliencemode(LUKS2only)
Reencryption resilience mode can be one of checksum, journal or none.
checksum: default mode, where individual checksums of ciphertext hotzone sectors are stored, so the
recovery process can detect which sectors were already reencrypted. It requires that the device
sector write is atomic.
journal: the hotzone is journaled in the binary area (so the data are written twice).
none: performance mode. There is no protection and the only way it’s safe to interrupt the
reencryption is similar to old offline reencryption utility.
Resilience modes can be changed unless datashift mode is used for operation initialization
(encryption with --reduce-device-size option)
--resilience-hashhash(LUKS2only)
The hash algorithm used with "--resilience checksum" only. The default hash is sha256. With other
resilience modes, the hash parameter is ignored.
--resume-only(LUKS2only)
Resume reencryption (any mode) operation already described in LUKS2 metadata. If no reencrypt
operation is initialized, the command with --resume-only parameter fails. Useful for resuming
reencrypt operation without accidentally triggering new reencryption operation.
--sector-sizebytes(LUKS2only)
Reencrypt device with new encryption sector size enforced.
WARNING: Increasing encryption sector size may break hosted filesystem. Do not run reencryption with
--force-offline-reencrypt if unsure what block size was filesystem formatted with.
--timeout,-t<numberofseconds>
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-idLUKS2reencryptioninitialization: Specify what keyslots (associated with selected token) to use for
LUKS2 reencryption. If reencryption operation changes effective volume key only keyslots associated
the token and unlocked successfully will be available after the reencryption operation is finished.
LUKS2reencryptionresume: Specify what token to use and allow token PIN prompt to take precedence
over interactive keyslot passphrase prompt. If omitted, all available tokens (not protected by PIN)
will be checked before proceeding further with passphrase prompt.
--token-onlyLUKS2reencryptioninitialization: Specify all keyslots associated with any token will be used for
LUKS2 reencryption. If reencryption operation changes effective volume key only keyslots associated
with any token will be available after the reencryption operation is finished.
LUKS2reencryptionresume: Do not proceed further with action if token based keyslot unlock failed.
Without the option, action asks for passphrase to proceed further.
It allows LUKS2 tokens protected by PIN to take precedence over interactive keyslot passphrase
prompt.
--token-typetypeLUKS2reencryptioninitialization: Specify what keyslots (associated with selected token type) to use
for LUKS2 reencryption. If reencryption operation changes effective volume key only keyslots
associated the token type and unlocked successfully will be available after the reencryption
operation is finished.
LUKS2reencryptionresume: Restrict tokens eligible for operation to specific token type. Mostly
useful when no --token-id is specified.
It allows LUKS2 type tokens protected by PIN to take precedence over interactive keyslot passphrase
prompt.
--tries,-T
How often the input of the passphrase shall be retried. The default is 3 tries.
--type<device-type>
Specifies required (encryption mode) or expected (other modes) LUKS format. Accepts only luks1 or
luks2.
--usage
Show short option help.
--use-directio(LUKS1only)
Use direct-io (O_DIRECT) for all read/write data operations related to block device undergoing
reencryption.
Useful if direct-io operations perform better than normal buffered operations (e.g. in virtual
environments).
--use-fsync(LUKS1only)
Use fsync call after every written block. This applies for reencryption log files as well.
--use-random, --use-urandom
Define which kernel random number generator will be used to create the volume key.
--uuid<UUID>
When used in encryption mode use the provided UUID for the new LUKS header instead of generating a
new one.
LUKS1(onlyindecryptionmode): To find out what UUID to pass look for temporary files
LUKS-UUID.[|log|org|new] of the interrupted decryption process.
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,--master-key-file(OBSOLETEalias)LUKS2: Provides current volume key stored in a file. It can be used to reencrypt the device with no
active keyslot together with --new-volume-key-file or --new-volume-key-keyring options.
LUKS1: See --new-volume-key-file.
--write-log(LUKS1only)
Update log file after every block write. This can slow down reencryption but will minimize data loss
in the case of system crash.
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