.TH CRYPTSETUP "8" "January 2019" "cryptsetup" "Maintenance Commands"

.SH NAME

cryptsetup - manage plain dm-crypt and LUKS encrypted volumes

.SH SYNOPSIS

.B cryptsetup <options> <action> <action args>

.SH DESCRIPTION

.PP

cryptsetup is used to conveniently setup dm-crypt managed

device-mapper mappings. These include plain dm-crypt volumes and

LUKS volumes. The difference is that LUKS uses a metadata header

and can hence offer more features than plain dm-crypt. On the other

hand, the header is visible and vulnerable to damage.

In addition, cryptsetup provides limited support for the use of

loop-AES volumes, TrueCrypt, VeraCrypt and BitLocker compatible volumes.

.SH PLAIN DM-CRYPT OR LUKS?

.PP

Unless you understand the cryptographic background well, use LUKS.

With plain dm-crypt there are a number of possible user errors

that massively decrease security. While LUKS cannot fix them

all, it can lessen the impact for many of them.

.SH WARNINGS

.PP

A lot of good information on the risks of using encrypted storage,

on handling problems and on security aspects can be found in the

\fICryptsetup FAQ\fR. Read it. Nonetheless, some risks deserve

to be mentioned here.

\fBBackup:\fR Storage media die. Encryption has no influence on that.

Backup is mandatory for encrypted data as well, if the data has any

worth. See the Cryptsetup FAQ for advice on how to do a backup of an

encrypted volume.

\fBCharacter encoding:\fR If you enter a

passphrase with special symbols, the passphrase can change

depending on character encoding. Keyboard settings can also change,

which can make blind input hard or impossible. For

example, switching from some ASCII 8-bit variant to UTF-8

can lead to a different binary encoding and hence different

passphrase seen by cryptsetup, even if what you see on

the terminal is exactly the same. It is therefore highly

recommended to select passphrase characters only from 7-bit

ASCII, as the encoding for 7-bit ASCII stays the same for

all ASCII variants and UTF-8.

\fBLUKS header:\fR If the header of a LUKS volume gets damaged,

all data is permanently lost unless you have a header-backup.

If a key-slot is damaged, it can only be restored from a header-backup

or if another active key-slot with known passphrase is undamaged.

Damaging the LUKS header is something people manage to do with

surprising frequency. This risk is the result of a trade-off

between security and safety, as LUKS is designed for fast and

secure wiping by just overwriting header and key-slot area.

\fBPreviously used partitions:\fR If a partition was previously used,

it is a very good idea to wipe filesystem signatures, data, etc. before

creating a LUKS or plain dm-crypt container on it.

For a quick removal of filesystem signatures, use "wipefs". Take care

though that this may not remove everything. In particular, MD RAID

signatures at the end of a device may survive. It also does not

remove data. For a full wipe, overwrite the whole partition before

container creation. If you do not know how to do that, the

cryptsetup FAQ describes several options.

.SH BASIC COMMANDS

The following are valid actions for all supported device types.

\fIopen\fR <device> <name> \-\-type <device_type>

.IP

Opens (creates a mapping with) <name> backed by device <device>.

Device type can be \fIplain\fR, \fIluks\fR (default), \fIluks1\fR, \fIluks2\fR,

\fIloopaes\fR or \fItcrypt\fR.

For backward compatibility there are \fBopen\fR command aliases:

\fBcreate\fR (argument-order <name> <device>): open \-\-type plain

.br

\fBplainOpen\fR: open \-\-type plain

.br

\fBluksOpen\fR: open \-\-type luks

.br

\fBloopaesOpen\fR: open \-\-type loopaes

.br

\fBtcryptOpen\fR: open \-\-type tcrypt

.br

\fBbitlkOpen\fR: open \-\-type bitlk

\fB<options>\fR are type specific and are described below

for individual device types. For \fBcreate\fR, the order of the <name>

and <device> options is inverted for historical reasons, all other

aliases use the standard \fB<device> <name>\fR order.

.PP

\fIclose\fR <name>

.IP

Removes the existing mapping <name> and wipes the key from kernel memory.

For backward compatibility there are \fBclose\fR command aliases:

\fBremove\fR, \fBplainClose\fR, \fBluksClose\fR, \fBloopaesClose\fR,

\fBtcryptClose\fR (all behaves exactly the same, device type is

determined automatically from active device).

\fB<options>\fR can be [\-\-deferred]

.PP

\fIstatus\fR <name>

.IP

Reports the status for the mapping <name>.

.PP

\fIresize\fR <name>

.IP

Resizes an active mapping <name>.

If \-\-size (in 512-bytes sectors) or \-\-device\-size are not specified,

the size is computed from the underlying device. For LUKS it is the size

of the underlying device without the area reserved for LUKS header

(see data payload offset in \fBluksDump\fR command).

For plain crypt device, the whole device size is used.

Note that this does not change the raw device geometry, it just

changes how many sectors of the raw device are represented

in the mapped device.

If cryptsetup detected volume key for active device loaded in kernel keyring

service, resize action would first try to retrieve

the key using a token and only if it failed it'd ask for a passphrase

to unlock a keyslot (LUKS) or to derive a volume key again (plain mode).

The kernel keyring is used by default for LUKS2 devices.

With LUKS2 device additional \fB<options>\fR can be [\-\-token\-id, \-\-token\-only,

\-\-key\-slot, \-\-key\-file, \-\-keyfile\-size, \-\-keyfile\-offset, \-\-timeout,

\-\-disable\-locks, \-\-disable\-keyring].

.PP

\fIrefresh\fR <name>

.IP

Refreshes parameters of active mapping <name>.

Updates parameters of active device <name> without need to deactivate the device

(and umount filesystem). Currently it supports parameters refresh on following

devices: LUKS1, LUKS2 (including authenticated encryption), plain crypt

and loopaes.

Mandatory parametrs are identical to those of an open action for respective

device type.

You may change following parameters on all devices \-\-perf\-same_cpu_crypt,

\-\-perf\-submit_from_crypt_cpus and \-\-allow\-discards.

Refreshing device without any optional parameter will refresh the device

with default setting (respective to device type).

\fBLUKS2 only:\fR

\-\-integrity\-no\-journal parameter affects only LUKS2 devices with

underlying dm-integrity device.

Adding option \-\-persistent stores any combination of device parameters

above in LUKS2 metadata (only after successful refresh operation).

\-\-disable\-keyring parameter refreshes a device with volume key passed

in dm-crypt driver.

.PP

\fIreencrypt\fR <device> or --active-name <name> [<new_name>]

.IP

Run resilient reencryption (LUKS2 device only).

There are 3 basic modes of operation:

\(bu device reencryption (\fIreencrypt\fR)

\(bu device encryption (\fIreencrypt\fR \-\-encrypt)

\(bu device decryption (\fIreencrypt\fR \-\-decrypt)

<device> or --active-name <name> is mandatory parameter.

With <device> parameter cryptsetup looks up active <device> dm mapping.

If no active mapping is detected, it starts offline reencryption otherwise online

reencryption takes place.

Reencryption process may be safely interrupted by a user via SIGTERM signal (ctrl+c).

To resume already initialized or interrupted reencryption, just run the cryptsetup

\fIreencrypt\fR command again to continue the reencryption operation.

Reencryption may be resumed with different \-\-resilience or \-\-hotzone\-size unless

implicit datashift resilience mode is used (reencrypt \-\-encrypt with \-\-reduce-device-size

option).

If the reencryption process was interrupted abruptly (reencryption process crash, system crash, poweroff)

it may require recovery. The recovery is currently run automatically on next activation (action \fIopen\fR)

when needed.

Optional parameter <new_name> takes effect only with \-\-encrypt option and it activates device <new_name>

immediately after encryption initialization gets finished. That's useful when device needs to be ready

as soon as possible and mounted (used) before full data area encryption is completed.

Action supports following additional \fB<options>\fR [\-\-encrypt, \-\-decrypt, \-\-device\-size,

\-\-resilience, \-\-resilience-hash, \-\-hotzone-size, \-\-init\-only, \-\-resume\-only,

\-\-reduce\-device\-size].

.SH PLAIN MODE

Plain dm-crypt encrypts the device sector-by-sector with a

single, non-salted hash of the passphrase. No checks

are performed, no metadata is used. There is no formatting operation.

When the raw device is mapped (opened), the usual device operations

can be used on the mapped device, including filesystem creation.

Mapped devices usually reside in /dev/mapper/<name>.

The following are valid plain device type actions:

\fIopen\fR \-\-type plain <device> <name>

.br

\fIcreate\fR <name> <device> (\fBOBSOLETE syntax\fR)

.IP

Opens (creates a mapping with) <name> backed by device <device>.

\fB<options>\fR can be [\-\-hash, \-\-cipher, \-\-verify-passphrase,

\-\-sector\-size, \-\-key-file, \-\-keyfile-offset, \-\-key-size,

\-\-offset, \-\-skip, \-\-size, \-\-readonly, \-\-shared, \-\-allow\-discards,

\-\-refresh]

Example: 'cryptsetup open \-\-type plain /dev/sda10 e1' maps the raw

encrypted device /dev/sda10 to the mapped (decrypted) device

/dev/mapper/e1, which can then be mounted, fsck-ed or have a

filesystem created on it.

.SH LUKS EXTENSION

LUKS, the Linux Unified Key Setup, is a standard for disk encryption.

It adds a standardized header at the start of the device,

a key-slot area directly behind the header and the bulk

data area behind that. The whole set is called a 'LUKS container'.

The device that a LUKS container resides on is called a 'LUKS device'.

For most purposes, both terms can be used interchangeably. But

note that when the LUKS header is at a nonzero offset

in a device, then the device is not a LUKS device anymore, but

has a LUKS container stored in it at an offset.

LUKS can manage multiple passphrases that can be individually revoked

or changed and that can be securely scrubbed from persistent

media due to the use of anti-forensic stripes. Passphrases

are protected against brute-force and dictionary

attacks by PBKDF2, which implements hash iteration and salting

in one function.

LUKS2 is a new version of header format that allows additional

extensions like different PBKDF algorithm or authenticated encryption.

You can format device with LUKS2 header if you specify

\fI\-\-type luks2\fR in \fIluksFormat\fR command.

For activation, the format is already recognized automatically.

Each passphrase, also called a

.B key

in this document, is associated with one of 8 key-slots.

Key operations that do not specify a slot affect the first slot

that matches the supplied passphrase or the first empty slot if

a new passphrase is added.

The \fB<device>\fR parameter can also be specified by a LUKS UUID in the

format UUID=<uuid>. Translation to real device name uses symlinks

in /dev/disk/by-uuid directory.

To specify a detached header, the \fB\-\-header\fR parameter can be used

in all LUKS commands and always takes precedence over the positional

\fB<device>\fR parameter.

The following are valid LUKS actions:

\fIluksFormat\fR <device> [<key file>]

.IP

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 can only call luksFormat on a LUKS device that is not mapped.

To use LUKS2, specify \fI\-\-type luks2\fR.

\fB<options>\fR 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, \-\-master\-key\-file, \-\-iter\-time, \-\-header,

\-\-pbkdf\-force\-iterations,

\-\-force\-password, \-\-disable-locks].

For LUKS2, additional \fB<options>\fR 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].

\fBWARNING:\fR Doing a luksFormat on an existing LUKS container will

make all data the old container permanently irretrievable unless

you have a header backup.

.PP

\fIopen\fR \-\-type luks <device> <name>

.br

\fIluksOpen\fR <device> <name> (\fBold syntax\fR)

.IP

Opens the LUKS device <device> and sets up a mapping <name> after

successful verification of the supplied passphrase.

First, the passphrase is searched in LUKS tokens. If it's not

found in any token and also the passphrase is not supplied via \-\-key-file,

the command prompts for it interactively.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-readonly, \-\-test\-passphrase,

\-\-allow\-discards, \-\-header, \-\-key-slot, \-\-master\-key\-file, \-\-token\-id,

\-\-token\-only, \-\-disable\-keyring, \-\-disable\-locks, \-\-type, \-\-refresh,

\-\-serialize\-memory\-hard\-pbkdf].

.PP

\fIluksSuspend\fR <name>

.IP

Suspends an active device (all IO operations will block

and accesses to the device will wait indefinitely)

and wipes the encryption

key from kernel memory. Needs kernel 2.6.19 or later.

After this operation you have to use \fIluksResume\fR to reinstate

the encryption key and unblock the device or \fIclose\fR to remove

the mapped device.

\fBWARNING:\fR never suspend the device on which the cryptsetup binary resides.

\fB<options>\fR can be [\-\-header, \-\-disable\-locks].

.PP

\fIluksResume\fR <name>

.IP

Resumes a suspended device and reinstates the encryption key.

Prompts interactively for a passphrase if \-\-key-file is not given.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-size, \-\-header,

\-\-disable\-keyring, \-\-disable\-locks, \-\-type]

.PP

\fIluksAddKey\fR <device> [<key file with new key>]

.IP

Adds a new passphrase. An existing passphrase must be supplied

interactively or via \-\-key-file.

The new passphrase to be added can be specified interactively

or read from the file given as positional argument.

\fBNOTE:\fR with \-\-unbound option the action creates new unbound

LUKS2 keyslot. The keyslot cannot be used for device activation.

If you don't pass new key via \-\-master\-key\-file option,

new random key is generated. Existing passphrase for any active keyslot

is not required.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-new\-keyfile\-offset,

\-\-new\-keyfile\-size, \-\-key\-slot, \-\-master\-key\-file,

\-\-force\-password, \-\-header, \-\-disable\-locks,

\-\-iter-time, \-\-pbkdf, \-\-pbkdf\-force\-iterations,

\-\-unbound, \-\-type, \-\-keyslot\-cipher, \-\-keyslot\-key\-size].

.PP

\fIluksRemoveKey\fR <device> [<key file with passphrase to be removed>]

.IP

Removes the supplied passphrase from the LUKS device. The

passphrase to be removed can be specified interactively,

as the positional argument or via \-\-key-file.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-header, \-\-disable\-locks, \-\-type]

\fBWARNING:\fR If you read the passphrase from stdin

(without further argument or with '-' as an argument

to \-\-key\-file), batch-mode (\-q) will be implicitly

switched on and no warning will be given when you remove the

last remaining passphrase from a LUKS container. Removing

the last passphrase makes the LUKS container permanently

inaccessible.

.PP

\fIluksChangeKey\fR <device> [<new key file>]

.IP

Changes an existing passphrase. The passphrase

to be changed must be supplied interactively or via \-\-key\-file.

The new passphrase can be supplied interactively or in

a file given as positional argument.

If a key-slot is specified (via \-\-key-slot), the passphrase

for that key-slot must be given and the new passphrase

will overwrite the specified key-slot. If no key-slot

is specified and there is still a free key-slot, then

the new passphrase will be put into a free key-slot before the

key-slot containing the old passphrase is purged. If there is

no free key-slot, then the key-slot with the old passphrase is

overwritten directly.

\fBWARNING:\fR If a key-slot is overwritten, a media failure

during this operation can cause the overwrite to fail after

the old passphrase has been wiped and make the LUKS container

inaccessible.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-new\-keyfile\-offset,

\-\-iter-time, \-\-pbkdf, \-\-pbkdf\-force\-iterations,

\-\-new\-keyfile\-size, \-\-key\-slot, \-\-force\-password, \-\-header,

\-\-disable\-locks, \-\-type, \-\-keyslot\-cipher, \-\-keyslot\-key\-size].

.PP

.PP

\fIluksConvertKey\fR <device>

.IP

Converts an existing LUKS2 keyslot to new pbkdf parameters. The

passphrase for keyslot to be converted must be supplied interactively

or via \-\-key\-file. If no \-\-pbkdf parameters are specified LUKS2

default pbkdf values will apply.

If a keyslot is specified (via \-\-key\-slot), the passphrase for that

keyslot must be given. If no keyslot is specified and there is still

a free keyslot, then the new parameters will be put into a free

keyslot before the keyslot containing the old parameters is

purged. If there is no free keyslot, then the keyslot with the old

parameters is overwritten directly.

\fBWARNING:\fR If a keyslot is overwritten, a media failure during

this operation can cause the overwrite to fail after the old

parameters have been wiped and make the LUKS container inaccessible.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-key\-slot, \-\-header, \-\-disable\-locks,

\-\-iter-time, \-\-pbkdf, \-\-pbkdf\-force\-iterations,

\-\-pbkdf\-memory, \-\-pbkdf\-parallel,

\-\-keyslot\-cipher, \-\-keyslot\-key\-size].

.PP

\fIluksKillSlot\fR <device> <key slot number>

.IP

Wipe the key-slot number <key slot> from the LUKS device. Except running

in batch-mode (\-q) a remaining passphrase must be supplied,

either interactively or via \-\-key-file.

This command can remove the last remaining key-slot, but requires

an interactive confirmation when doing so. Removing the last

passphrase makes a LUKS container permanently inaccessible.

\fB<options>\fR can be [\-\-key\-file, \-\-keyfile\-offset,

\-\-keyfile\-size, \-\-header, \-\-disable\-locks, \-\-type].

\fBWARNING:\fR If you read the passphrase from stdin

(without further argument or with '-' as an argument

to \-\-key-file), batch-mode (\-q) will be implicitly

switched on and no warning will be given when you remove the

last remaining passphrase from a LUKS container. Removing

the last passphrase makes the LUKS container permanently

inaccessible.

\fBNOTE:\fR If there is no passphrase provided (on stdin or through

\-\-key-file argument) and batch-mode (\-q) is active, the

key-slot is removed without any other warning.

.PP

\fIerase\fR <device>

.br

\fIluksErase\fR <device>

.IP

Erase all keyslots and make the LUKS container permanently inaccessible.

You do not need to provide any password for this operation.

\fBWARNING:\fR This operation is irreversible.

.PP

\fIluksUUID\fR <device>

.IP

Print the UUID of a LUKS device.

.br

Set new UUID if \fI\-\-uuid\fR option is specified.

.PP

\fIisLuks\fR <device>

.IP

Returns true, if <device> is a LUKS device, false otherwise.

Use option \-v to get human-readable feedback. 'Command successful.'

means the device is a LUKS device.

By specifying \-\-type you may query for specific LUKS version.

.PP

\fIluksDump\fR <device>

.IP

Dump the header information of a LUKS device.

If the \-\-dump\-master\-key option is used, the LUKS device master key is

dumped instead of the keyslot info. Together with \-\-master\-key\-file option,

master key is dumped to a file instead of standard output. Beware that the

master key cannot be changed without reencryption and can be used to decrypt

the data stored in the LUKS container without a passphrase and even without the

LUKS header. This means that if the master key is compromised, the whole device

has to be erased or reencrypted to prevent further access. Use this option carefully.

To dump the master key, a passphrase has to be supplied,

either interactively or via \-\-key\-file.

To dump unbound key (LUKS2 format only), \-\-unbound parameter, specific \-\-key-slot

id and proper passphrase has to be supplied, either interactively or via \-\-key\-file.

Optional \-\-master\-key\-file parameter enables unbound keyslot dump to a file.

\fB<options>\fR can be [\-\-dump\-master\-key, \-\-key\-file,

\-\-keyfile\-offset, \-\-keyfile\-size, \-\-header, \-\-disable\-locks,

\-\-master\-key\-file, \-\-type, \-\-unbound, \-\-key-slot].

\fBWARNING:\fR If \-\-dump\-master\-key is used with \-\-key\-file

and the argument to \-\-key\-file is '-', no validation question

will be asked and no warning given.

.PP

\fIluksHeaderBackup\fR <device> \-\-header\-backup\-file <file>

.IP

Stores a binary backup of the LUKS header and keyslot area.

.br

Note: Using '-' as filename writes the header backup to a file named '-'.

\fBWARNING:\fR This backup file and a passphrase valid

at the time of backup allows decryption of the

LUKS data area, even if the passphrase was later changed or

removed from the LUKS device. Also note that with a header

backup you lose the ability to securely wipe the LUKS

device by just overwriting the header and key-slots. You

either need to securely erase all header backups in

addition or overwrite the encrypted data area as well.

The second option is less secure, as some sectors

can survive, e.g. due to defect management.

.PP

\fIluksHeaderRestore\fR <device> \-\-header\-backup\-file <file>

.IP

Restores a binary backup of the LUKS header and keyslot area

from the specified file.

.br

Note: Using '-' as filename reads the header backup from a file named '-'.

\fBWARNING:\fR Header and keyslots will be replaced, only

the passphrases from the backup will work afterward.

This command requires that the master key size and data offset

of the LUKS header already on the device and of the header backup

match. Alternatively, if there is no LUKS header on the device,

the backup will also be written to it.

.PP

\fItoken\fR <add|remove|import|export> <device>

.IP

Action \fIadd\fR creates new keyring token to enable auto-activation of the device.

For the auto-activation, the passphrase must be stored in keyring with the specified

description. Usually, the passphrase should be stored in \fIuser\fR or

\fIuser-session\fR keyring.

The \fItoken\fR command is supported only for LUKS2.

For adding new keyring token, option \-\-key\-description is mandatory.

Also, new token is assigned to key slot specified with \-\-key\-slot option or to all

active key slots in the case \-\-key\-slot option is omitted.

To remove existing token, specify the token ID which should be removed with

\-\-token\-id option.

\fBWARNING:\fR The action \fItoken remove\fR removes any token type, not just \fIkeyring\fR

type from token slot specified by \-\-token\-id option.

Action \fIimport\fR can store arbitrary valid token json in LUKS2 header. It may be passed via

standard input or via file passed in \-\-json\-file option. If you specify \-\-key\-slot then

successfully imported token is also assigned to the key slot.

Action \fIexport\fR writes requested token json to a file passed with \-\-json\-file or

to standard output.

\fB<options>\fR can be [\-\-header, \-\-token\-id, \-\-key\-slot, \-\-key\-description,

\-\-disable\-locks, \-\-disable\-keyring, \-\-json\-file].

.PP

\fIconvert\fR <device> \-\-type <format>

.IP

Converts the device between LUKS1 and LUKS2 format (if possible).

The conversion will not be performed if there is an additional LUKS2 feature or LUKS1 has

unsupported header size.

Conversion (both directions) must be performed on inactive device. There must not be active

dm-crypt mapping established for LUKS header requested for conversion.

\fB\-\-type\fR option is mandatory with following accepted values: \fIluks1\fR or \fIluks2\fR.

\fBWARNING:\fR The \fIconvert\fR action can destroy the LUKS header in the case of a crash

during conversion or if a media error occurs.

Always create a header backup before performing this operation!

\fB<options>\fR can be [\-\-header, \-\-type].

.PP

\fIconfig\fR <device>

.IP

Set permanent configuration options (store to LUKS header).

The \fIconfig\fR command is supported only for LUKS2.

The permanent options can be \fI\-\-priority\fR to set priority (normal, prefer, ignore)

for keyslot (specified by \fI\-\-key\-slot\fR) or \fI\-\-label\fR and \fI\-\-subsystem\fR.

\fB<options>\fR can be [\-\-priority, \-\-label, \-\-subsystem, \-\-key\-slot, \-\-header].

.SH loop-AES EXTENSION

cryptsetup supports mapping loop-AES encrypted partition using

a compatibility mode.

.PP

\fIopen\fR \-\-type loopaes <device> <name> \-\-key\-file <keyfile>

.br

\fIloopaesOpen\fR <device> <name> \-\-key\-file <keyfile>  (\fBold syntax\fR)

.IP

Opens the loop-AES <device> and sets up a mapping <name>.

If the key file is encrypted with GnuPG, then you have to use

\-\-key\-file=\- and decrypt it before use, e.g. like this:

.br

gpg \-\-decrypt <keyfile> | cryptsetup loopaesOpen \-\-key\-file=\-

<device> <name>

\fBWARNING:\fR The loop-AES extension cannot use the direct input of key file

on real terminal because the keys are separated by end-of-line and only part

of the multi-key file would be read.

.br

If you need it in script, just use the pipe redirection:

.br

echo $keyfile | cryptsetup loopaesOpen \-\-key\-file=\- <device> <name>

Use \fB\-\-keyfile\-size\fR to specify the proper key length if needed.

Use \fB\-\-offset\fR to specify device offset. Note that the units

need to be specified in number of 512 byte sectors.

Use \fB\-\-skip\fR to specify the IV offset. If the original device

used an offset and but did not use it in IV sector calculations,

you have to explicitly use \fB\-\-skip 0\fR in addition to the offset

parameter.

Use \fB\-\-hash\fR to override the default hash function for

passphrase hashing (otherwise it is detected according to key

size).

\fB<options>\fR can be [\-\-key\-file, \-\-key\-size, \-\-offset, \-\-skip,

\-\-hash, \-\-readonly, \-\-allow\-discards, \-\-refresh].

.PP

See also section 7 of the FAQ and \fBhttp://loop-aes.sourceforge.net\fR

for more information regarding loop-AES.

.SH TCRYPT (TrueCrypt-compatible and VeraCrypt) EXTENSION

cryptsetup supports mapping of TrueCrypt, tcplay or VeraCrypt

(with \fB\-\-veracrypt\fR option) encrypted partition

using a native Linux kernel API.

Header formatting and TCRYPT header change is not supported, cryptsetup

never changes TCRYPT header on-device.

TCRYPT extension requires kernel userspace

crypto API to be available (introduced in Linux kernel 2.6.38).

If you are configuring kernel yourself, enable

"User-space interface for symmetric key cipher algorithms" in

"Cryptographic API" section (CRYPTO_USER_API_SKCIPHER .config option).

Because TCRYPT header is encrypted, you have to always provide valid

passphrase and keyfiles.

Cryptsetup should recognize all header variants, except legacy cipher chains

using LRW encryption mode with 64 bits encryption block (namely Blowfish

in LRW mode is not recognized, this is limitation of kernel crypto API).

To recognize a VeraCrypt device use the \fB\-\-veracrypt\fR option.

VeraCrypt is just extension of TrueCrypt header with increased

iteration count so unlocking can take quite a lot of time (in comparison

with TCRYPT device).

To open a VeraCrypt device with a custom Personal Iteration Multiplier (PIM)

value, \fBadditionally to \-\-veracrypt \fR use either the

\fB\-\-veracrypt\-pim=<PIM>\fR option to directly specify the PIM on the command-

line or use \fB\-\-veracrypt\-query\-pim\fR to be prompted for the PIM.

The PIM value affects the number of iterations applied during key derivation. Please refer to

\fBhttps://www.veracrypt.fr/en/Personal%20Iterations%20Multiplier%20%28PIM%29.html\fR

for more detailed information.

\fBNOTE:\fR Activation with \fBtcryptOpen\fR is supported only for cipher chains

using LRW or XTS encryption modes.

The \fBtcryptDump\fR command should work for all recognized TCRYPT devices

and doesn't require superuser privilege.

To map system device (device with boot loader where the whole encrypted

system resides) use \fB\-\-tcrypt\-system\fR option.

You can use partition device as the parameter (parameter must be real partition

device, not an image in a file), then only this partition is mapped.

If you have the whole TCRYPT device as a file image and you want to map multiple

partition encrypted with system encryption, please create loopback mapping

with partitions first (\fBlosetup \-P\fR, see \fPlosetup(8)\fR man page for more info),

and use loop partition as the device parameter.

If you use the whole base device as a parameter, one device for the whole system

encryption is mapped. This mode is available only for backward compatibility

with older cryptsetup versions which mapped TCRYPT system encryption

using the whole device.

To use hidden header (and map hidden device, if available),

use \fB\-\-tcrypt\-hidden\fR option.

To explicitly use backup (secondary) header, use \fB\-\-tcrypt\-backup\fR

option.

\fBNOTE:\fR There is no protection for a hidden volume if

the outer volume is mounted. The reason is that if there

were any protection, it would require some metadata describing

what to protect in the outer volume and the hidden volume would

become detectable.

.PP

\fIopen\fR \-\-type tcrypt <device> <name>

.br

\fItcryptOpen\fR <device> <name>  (\fBold syntax\fR)

.IP

Opens the TCRYPT (a TrueCrypt-compatible) <device> and sets up

a mapping <name>.

\fB<options>\fR can be [\-\-key\-file, \-\-tcrypt\-hidden,

\-\-tcrypt\-system, \-\-tcrypt\-backup, \-\-readonly, \-\-test\-passphrase,

\-\-allow-discards, \-\-veracrypt, \-\-veracrypt\-pim, \-\-veracrypt\-query\-pim].

The keyfile parameter allows a combination of file content with the

passphrase and can be repeated. Note that using keyfiles is compatible

with TCRYPT and is different from LUKS keyfile logic.

\fBWARNING:\fR Option \fB\-\-allow\-discards\fR cannot be combined with

option \fB\-\-tcrypt\-hidden\fR. For normal mapping, it can cause

the \fBdestruction of hidden volume\fR (hidden volume appears as unused space

for outer volume so this space can be discarded).

.PP

\fItcryptDump\fR <device>

.IP

Dump the header information of a TCRYPT device.

If the \-\-dump\-master\-key option is used, the TCRYPT device master key

is dumped instead of TCRYPT header info. Beware that the master key

(or concatenated master keys if cipher chain is used)

can be used to decrypt the data stored in the TCRYPT container without

a passphrase.

This means that if the master key is compromised, the whole device has

to be erased to prevent further access. Use this option carefully.

\fB<options>\fR can be [\-\-dump\-master\-key, \-\-key\-file,

\-\-tcrypt\-hidden, \-\-tcrypt\-system, \-\-tcrypt\-backup].

The keyfile parameter allows a combination of file content with the

passphrase and can be repeated.

.PP

See also \fBhttps://en.wikipedia.org/wiki/TrueCrypt\fR for more information regarding

TrueCrypt.

Please note that cryptsetup does not use TrueCrypt code, please report

all problems related to this compatibility extension to the cryptsetup project.

.SH BITLK (Windows BitLocker-compatible) EXTENSION (EXPERIMENTAL)

cryptsetup supports mapping of BitLocker and BitLocker to Go encrypted partition

using a native Linux kernel API.

Header formatting and BITLK header changes are not supported, cryptsetup

never changes BITLK header on-device.

\fBWARNING:\fR This extension is EXPERIMENTAL.

BITLK extension requires kernel userspace crypto API to be available

(for details see TCRYPT section).

Cryptsetup should recognize all BITLK header variants, except legacy

header used in Windows Vista systems and partially decrypted BitLocker devices.

Activation of legacy devices encrypted in CBC mode requires at least

Linux kernel version 5.3 and for devices using Elephant diffuser kernel 5.6.

The \fBbitlkDump\fR command should work for all recognized BITLK devices

and doesn't require superuser privilege.

For unlocking with the \fBopen\fR a password or a recovery passphrase must

be provided. Other unlocking methods (TPM, SmartCard) are not supported.

.PP

\fIopen\fR \-\-type bitlk <device> <name>

.br

\fIbitlkOpen\fR <device> <name>  (\fBold syntax\fR)

.IP

Opens the BITLK (a BitLocker-compatible) <device> and sets up

a mapping <name>.

\fB<options>\fR can be [\-\-key\-file, \-\-readonly, \-\-test\-passphrase,

\-\-allow-discards].

.PP

\fIbitlkDump\fR <device>

.IP

Dump the header information of a BITLK device.

Please note that cryptsetup does not use any Windows BitLocker code, please report

all problems related to this compatibility extension to the cryptsetup project.

.SH MISCELLANEOUS

.PP

\fIrepair\fR <device>

.IP

Tries to repair the device metadata if possible. Currently supported only

for LUKS device type.

This command is useful to fix some known benign LUKS metadata

header corruptions. Only basic corruptions of unused keyslot

are fixable. This command will only change the LUKS header, not

any key-slot data. You may enforce LUKS version by adding \-\-type

option.

\fBWARNING:\fR Always create a binary backup of the original

header before calling this command.

.PP

\fIbenchmark\fR <options>

.IP

Benchmarks ciphers and KDF (key derivation function).

Without parameters, it tries to measure few common configurations.

To benchmark other ciphers or modes, you need to specify \fB\-\-cipher\fR

and \fB\-\-key\-size\fR options or \fB\-\-hash\fR for KDF test.

\fBNOTE:\fR This benchmark is using memory only and is only informative.

You cannot directly predict real storage encryption speed from it.

For testing block ciphers, this benchmark requires kernel userspace

crypto API to be available (introduced in Linux kernel 2.6.38).

If you are configuring kernel yourself, enable

"User-space interface for symmetric key cipher algorithms" in

"Cryptographic API" section (CRYPTO_USER_API_SKCIPHER .config option).

\fB<options>\fR can be [\-\-cipher, \-\-key\-size, \-\-hash].

.SH OPTIONS

.TP

.B "\-\-verbose, \-v"

Print more information on command execution.

.TP

.B "\-\-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.

.TP

.B "\-\-type <device-type>

Specifies required device type, for more info

read \fIBASIC COMMANDS\fR section.

.TP

.B "\-\-hash, \-h \fI<hash\-spec>\fR"

Specifies the passphrase hash for \fIopen\fR (for plain and

loopaes device types).

Specifies the hash used in the LUKS key setup scheme and volume key digest

for \fIluksFormat\fR. The specified hash is used as hash-parameter

for PBKDF2 and for the AF splitter.

The specified hash name is passed to the compiled-in crypto backend.

Different backends may support different hashes.

For \fIluksFormat\fR, the hash

algorithm must provide at least 160 bits of output, which

excludes, e.g., MD5. Do not use a non-crypto hash like

\fB"crc32"\fR as this breaks security.

Values compatible with old version of cryptsetup are

\fB"ripemd160"\fR for \fIopen \-\-type plain\fR and

\fB"sha1"\fR for \fIluksFormat\fR.

Use \fIcryptsetup \-\-help\fR to show the defaults.

.TP

.B "\-\-cipher, \-c \fI<cipher\-spec>\fR"

Set the cipher specification string.

\fIcryptsetup \-\-help\fR shows the compiled-in defaults.

The current default in the distributed sources is

"aes-cbc-essiv:sha256" for plain dm-crypt and

"aes-xts-plain64" for LUKS.

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.

XTS mode requires kernel 2.6.24 or later and plain64 requires