CRYPTSETUP-REENCRYPT(8)	     Maintenance Commands      CRYPTSETUP-REENCRYPT(8)

NAME
       cryptsetup-reencrypt - reencrypt LUKS encrypted volumes in-place

SYNOPSIS
       cryptsetup reencrypt [<options>] <device> or --active-name <name>
       [<new_name>]

DESCRIPTION
       Run LUKS device reencryption.

       There are 3 basic modes of operation:

       •   device reencryption (reencrypt)

       •   device encryption (reencrypt --encrypt/--new/-N)

       •   device decryption (reencrypt --decrypt)

       <device> or --active-name <name> (LUKS2 only) is mandatory parameter.

       Cryptsetup reencrypt action can be used to change reencryption
       parameters, which otherwise require full on-disk data change
       (re-encryption).	 The reencrypt action reencrypts data on the LUKS
       device in-place.

       You can regenerate volume key (the real key used in on-disk encryption
       unlocked by passphrase), cipher, cipher mode or encryption sector size
       (LUKS2 only).

       If you need to use both luksChangeKey and reencrypt (e.g., to recover
       from a leak), you need to use them in that order to avoid leaking the
       new volume key.

       The reencryption process may be safely interrupted by a user via SIGINT
       signal (ctrl+c).	 The same applies to the SIGTERM signal (i.e., issued
       by systemd during system shutdown).

       For in-place encryption mode, the reencrypt action additionally takes
       all options available for the luksFormat action for the respective LUKS
       version (see cryptsetup-luksFormat man page for more details).  See
       cryptsetup-luksFormat(8).

       Note that for encrypt and decrypt mode, the whole device must be
       treated as unencrypted — there are no guarantees of confidentiality as
       part of the device contains plaintext.

       ALWAYS BE SURE YOU HAVE RELIABLE BACKUP BEFORE USING THIS ACTION ON
       LUKS DEVICE.

       <options> can be [--batch-mode, --block-size, --cipher, --debug,
       --debug-json, --decrypt, --device-size, --disable-locks, --encrypt,
       --force-offline-reencrypt, --hash, --header, --hotzone-size,
       --iter-time, --init-only, --keep-key, --key-file, --key-size,
       --key-slot, --keyfile-offset, --keyfile-size, --tries, --timeout,
       --pbkdf, --pbkdf-force-iterations, --pbkdf-memory, --pbkdf-parallel,
       --progress-frequency, --progress-json, --reduce-device-size,
       --resilience, --resilience-hash, --resume-only, --sector-size,
       --use-directio, --use-random, --use-urandom, --use-fsync, --uuid,
       --verbose, --volume-key-file, --write-log].

LUKS2 REENCRYPTION
       With the <device> parameter, cryptsetup looks up the active <device> dm
       mapping.	 If no active mapping is detected, it starts offline LUKS2
       reencryption; otherwise, online reencryption occurs.

       To resume already initialized or interrupted reencryption, just run the
       cryptsetup reencrypt command again to continue the reencryption
       operation.  Reencryption may be resumed with different --resilience or
       --hotzone-size unless implicit datashift resilience mode is used:
       either encrypt mode with --reduce-device-size option or decrypt mode
       with original LUKS2 header exported in --header file.

       If the reencryption process was interrupted abruptly (reencryption
       process crash, system crash, or power off), it may require recovery.
       The recovery is run automatically on next activation (action open) when
       needed or explicitly by the user (action repair).

       The optional parameter <new_name> takes effect only with the encrypt
       option, and it activates device <new_name> immediately after encryption
       initialization is finished.  That’s useful when the device needs to be
       ready as soon as possible and mounted (used) before full data area
       encryption is completed.

LUKS1 REENCRYPTION
       The current working directory must be writable, and temporary files
       created during reencryption must be present.  During reencryption, the
       LUKS1 device is marked unavailable and must be offline (no dm-crypt
       mapping or mounted filesystem).

       WARNING: The LUKS1 reencryption code is not resistant to hardware or
       kernel failures during reencryption (you can lose your data in this
       case).

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.

       --block-size value (LUKS1 only)
	   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 the data segment
	   only.

	   LUKS1: Set the cipher specification string for the data segment and
	   keyslots.

	   The default cipher is applied if the cipher specification is
	   omitted in encrypt mode.

	   In reencrypt mode, if no new cipher specification is requested, the
	   existing cipher will remain.	 The only exception is if the cipher
	   is "cipher_null", then the default cipher is used.

	   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.

       --decrypt
	   Initialize (and run) device decryption mode.

       --device-size size[units]
	   Instead of the real device size, use the specified value.  It means
	   that only the 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.

	   The sum of --device-size and --reduce-device-size values must not
	   exceed the real device size.

	   WARNING: This is a destructive operation.  Data beyond
	   --device-size limit may be lost after the operation is 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 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.

	   With locking disabled, LUKS2 images in files can be fully
	   (re)encrypted offline without the need for superuser privileges
	   provided that the used block ciphers are available in the 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) the device in-place encryption mode.

       --force-no-keyslots (LUKS2 only)
	   Enforce initialization of reencryption operation with additional
	   --volume-key-file, --new-volume-key-file, --volume-key-keyring or
	   --new-volume-key-keyring parameters.	 It would result in the
	   deletion of all remaining LUKS2 keyslots containing the volume key.

	   LUKS2 keyslot with the new volume key may be added after the
	   reencryption operation is finished.	See cryptsetup-luksAddKey(8)
	   command.

	   WARNING: Use with extreme caution!  If you lose the volume key
	   stored in a file or in a kernel keyring before adding the LUKS2
	   keyslot containing the new volume key, the device will become
	   unusable, and all data will be lost.

       --force-offline-reencrypt (LUKS2 only)
	   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 a
	   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.

	   If this parameter is not specified, the default hash algorithm is
	   always used for a new LUKS1 device header.

	   LUKS2: Ignored unless new keyslot pbkdf algorithm is set to PBKDF2
	   (see --pbkdf).

       --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.

	   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 the
	   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 the head of the data device so that
	   data can be moved at the original LUKS2 header location.  Later on,
	   the decryption operation continues as if the ordinary detached
	   header was passed.

	   WARNING: Never put an exported header file in a filesystem on top
	   of the device you are about to decrypt!  It would cause a deadlock.

       --help, -?
	   Show help text and default parameters.

       --hotzone-size size (LUKS2 only)
	   This option can be used to set an upper limit on the size of the
	   reencryption area (hotzone).	 The size can be specified with a unit
	   suffix (for example, 50M).  Note that the 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 the
	   head of the data device, the option specifies how large is the
	   first data segment moved from the original data offset pointer.

       --init-only (LUKS2 only)
	   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 <number of milliseconds>
	   The number of milliseconds to spend with PBKDF passphrase
	   processing for the new LUKS header.

       --keep-key
	   LUKS2: Do not change the effective volume key, and change other
	   parameters if requested.

	   LUKS1: Reencrypt only the LUKS1 header and keyslots.	 Skips data
	   in-place reencryption.

       --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.

	   The --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 the new LUKS device).

	   If this option is not used, cryptsetup will ask for all active
	   keyslot passphrases.

       --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
	   LUKS2: Provide current key size in bits.  The argument has to be a
	   multiple of 8.  Useful when specifying the size of the 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 keyslot is selected for the new key.

	   For reencryption mode, it selects a specific keyslot (and
	   passphrase) that can be used to unlock the new volume key.  If
	   used, all other keyslots get removed after the reencryption
	   operation is finished.

	   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).

       --new-key-size bits
	   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 the 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 the new key size,
	   you can destructively shrink the device with --reduce-device-size
	   option.

       --new-volume-key-file file
	   Use (set) the new volume key stored in a file.  The option must be
	   paired with --new-key-size parameter when initializing the
	   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 <key description>
	   Use (set) the new volume key stored in a keyring.

	   The size of the key stored in a keyring must be compatible with the
	   new cipher used in the reencryption operation.  See /proc/crypto
	   for more information.  Note that the key size in /proc/crypto is
	   stated in bytes.

	   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 the KEY IDENTIFIERS section of
	   keyctl(1).  When no %<key type>: 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 <number of 512 byte sectors>
	   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 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 reencryption 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.

       --reduce-device-size size
	   This means that the last size sectors on the original device will
	   be lost, and data will be effectively shifted by the specified
	   number of sectors.

	   It could be useful if you added some space to the underlying
	   partition or logical volume (so the ast 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 the original first data segment.	 The former
	   first data segment is replaced with LUKS2 header (half the size
	   value), and plaintext data is shifted backwards (again half the
	   size value) while being encrypted.

	   The recommended minimum size is twice the default LUKS2 header size
	   (--reduce-device-size 32M) for encryption mode.

	   The sum of --device-size and --reduce-device-size values must not
	   exceed the real device size.

	   LUKS1: Enlarge the data offset to the specified value by shrinking
	   the device size.

	   You cannot shrink the device by more than 64 MiB (131072 sectors).

       --resilience mode (LUKS2 only)
	   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 an old
	   offline reencryption utility.

	   Resilience modes can be changed unless datashift mode is used for
	   operation initialization (encryption with --reduce-device-size
	   option).

       --resilience-hash hash (LUKS2 only)
	   The hash algorithm is used with "--resilience checksum" only.  The
	   default hash is sha256.  With other resilience modes, the hash
	   parameter is ignored.

       --resume-only (LUKS2 only)
	   Resume reencryption (any mode) operation that is already described
	   in LUKS2 metadata.  If no reencrypt operation is initialized, the
	   command with --resume-only parameter fails.	Useful for resuming
	   the reencrypt operation without accidentally triggering a new
	   reencryption operation.

       --sector-size bytes (LUKS2 only)
	   Reencrypt the device with a new encryption sector size enforced.

	   WARNING: Increasing the encryption sector size may break the hosted
	   filesystem.	Do not run reencryption with --force-offline-reencrypt
	   if unsure what block size the filesystem was formatted with.

	   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.

       --token-id
	   LUKS2 reencryption initialization: Specify what keyslots
	   (associated with the selected token) to use for LUKS2 reencryption.
	   If the reencryption operation changes the effective volume key,
	   only keyslots associated with the token and unlocked successfully
	   will be available after the reencryption operation is finished.

	   LUKS2 reencryption resume: Specify what token to use and allow the
	   token PIN prompt to take precedence over the interactive keyslot
	   passphrase prompt.  If omitted, all available tokens (not protected
	   by PIN) will be checked before proceeding further with the
	   passphrase prompt.

       --token-only
	   LUKS2 reencryption initialization: Specify that all keyslots
	   associated with any token will be used for LUKS2 reencryption.  If
	   the reencryption operation changes the effective volume key, only
	   keyslots associated with any token will be available after the
	   reencryption operation is finished.

	   LUKS2 reencryption resume: Do not proceed further with the action
	   if the token-based keyslot unlock failed.  Without the option, the
	   action asks for a passphrase to proceed further.

	   It allows LUKS2 tokens protected by PIN to take precedence over the
	   interactive keyslot passphrase prompt.

       --token-type type
	   LUKS2 reencryption initialization: Specify what keyslots
	   (associated with the selected token type) to use for LUKS2
	   reencryption.  If the reencryption operation changes the effective
	   volume key, only keyslots associated with the token type and
	   unlocked successfully will be available after the reencryption
	   operation is finished.

	   LUKS2 reencryption resume: Restrict tokens eligible for operation
	   to a specific token type.  Mostly useful when no --token-id is
	   specified.

	   It allows LUKS2 type tokens protected by PIN to take precedence
	   over the interactive keyslot passphrase prompt.

       --tries, -T
	   How often the input of the passphrase shall be retried.  The
	   default is 3 tries.

       --type type
	   Specifies required (encryption mode) or expected (other modes) LUKS
	   format.  Accepts only luks1 or luks2.

       --usage
	   Show short option help.

       --use-directio (LUKS1 only)
	   Use direct-io (O_DIRECT) for all read/write data operations related
	   to the block device undergoing reencryption.

	   Useful if direct-io operations perform better than normal buffered
	   operations (e.g., in virtual environments).

       --use-fsync (LUKS1 only)
	   Use the fsync call after every written block.  This applies to
	   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 (only in decryption mode): 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 file, --master-key-file file (OBSOLETE alias)
	   LUKS2: Provides the 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 (LUKS1 only)
	   Update the log file after every block is written.  This can slow
	   down reencryption, but it will minimize data loss in the case of a
	   system crash.

EXAMPLES
       You may drop --type luks2 option as long as LUKS2 format is default.

   LUKS2 ENCRYPTION EXAMPLES
       Encrypt LUKS2 device (in-place).	 Make sure the last 32 MiB on
       /dev/plaintext is unused (e.g., does not contain filesystem data):

       cryptsetup reencrypt --encrypt --type luks2 --reduce-device-size 32m
       /dev/plaintext_device

       Encrypt LUKS2 device (in-place).	 Only the initial 1 GiB of original
       /dev/plaintext data is encrypted while being shifted backwards.	Make
       sure the last 32 MiB (tail) on the data device is unused (e.g., does
       not contain any data):

       cryptsetup reencrypt --encrypt --type luks2 --device-size 1g
       --reduce-device-size 32m /dev/plaintext_device

       Encrypt LUKS2 device (in-place) with detached header, put in a file:

       cryptsetup reencrypt --encrypt --type luks2 --header my_luks2_header
       /dev/plaintext_device

       Initialize LUKS2 in-place encryption operation only and activate the
       device (not yet encrypted):

       cryptsetup reencrypt --encrypt --type luks2 --init-only
       --reduce-device-size 32m /dev/plaintext_device my_future_luks_device

       Resume online encryption on the device initialized in the example
       above:

       cryptsetup reencrypt --resume-only /dev/plaintext_device or cryptsetup
       reencrypt --active-name my_future_luks_device

   LUKS2 REENCRYPTION EXAMPLES
       Reencrypt LUKS2 device (refresh volume key only):

       cryptsetup reencrypt /dev/encrypted_device

       Reencrypt LUKS2 device using keyslot(s) associated with the token 3.
       All other keyslots will be removed after the reencryption finishes.

       cryptsetup reencrypt --token-id 3 /dev/encrypted_device

       Reencrypt LUKS2 device using keyslots associated with all
       'systemd-tpm2' tokens.  All other keyslots will be removed after the
       reencryption finishes.

       cryptsetup reencrypt --token-type systemd-tpm2 /dev/encrypted_device

   LUKS2 DECRYPTION EXAMPLES
       Decrypt LUKS2 device with header put in the head of the data device
       (header file does not exist):

       cryptsetup reencrypt --decrypt --header /export/header/to/file
       /dev/encrypted_device

       Decrypt LUKS2 device with detached header (header file exists):

       cryptsetup reencrypt --decrypt --header detached-luks2-header
       /dev/encrypted_device

       Resume interrupted LUKS2 decryption:

       cryptsetup reencrypt --resume-only --header luks2-hdr-file
       /dev/encrypted_device

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 the 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 2.8.1		  2025-08-13	       CRYPTSETUP-REENCRYPT(8)