-.TH CRYPTSETUP "8" "March 2005" "cryptsetup" "Maintenance Commands"
+.TH CRYPTSETUP "8" "May 2012" "cryptsetup" "Maintenance Commands"
.SH NAME
-cryptsetup - setup cryptographic volumes for dm-crypt (including LUKS extension)
+cryptsetup - manage plain dm-crypt and LUKS encrypted volumes
.SH SYNOPSIS
-
.B cryptsetup <options> <action> <action args>
-
.SH DESCRIPTION
-.\" Add any additional description here
.PP
-cryptsetup is used to conveniently setup dm-crypt managed device-mapper mappings. For basic dm-crypt mappings, there are five operations.
-.SH ACTIONS
-These strings are valid for \fB<action>\fR, followed by their \fB<action args>\fR:
-
-\fIcreate\fR <name> <device>
+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.
+.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 backup of an
+encrypted volume.
+
+\fBCharacter encoding:\fR If you enter a
+passphrase with special symbols, the passphrase can change
+depending 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 to that, the
+cryptsetup FAQ describes several options.
+
+.SH BASIC COMMANDS
+The following are valid actions for all supported device types.
+
+\fIopen\fR <name> <device> \-\-type <device_type>
.IP
-creates a mapping with <name> backed by device <device>.
-<options> can be [\-\-hash, \-\-cipher, \-\-verify-passphrase, \-\-key-file, \-\-key-size, \-\-offset, \-\-skip, \-\-readonly]
+Opens (creates a mapping) with <name> backed by device <device>.
+
+Device type can be \fIplain\fR, \fIluks\fR (default), \fIloopaes\fR
+or \fItcrypt\fR.
+
+For backward compatibility there are \fBopen\fR command aliases:
+
+\fBcreate\fR: open \-\-type plain <device> <name>\fR switched arguments)
+.br
+\fBplainOpen\fR: open \-\-type plain
+.br
+\fBluksOpen\fR: open \-\-type luks
+.br
+\fBloopaesOpen\fR: open \-\-type loopaes
+.br
+\fBtcryptOpen\fR: open \-\-type tcrypt
+
+\fB<options>\fR are type specific and are described below
+for individual device types.
.PP
-\fIremove\fR <name>
+\fIclose\fR <name>
.IP
-removes an existing mapping <name>. No options.
+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).
.PP
\fIstatus\fR <name>
.IP
-reports the status for the mapping <name>. No options.
+Reports the status for the mapping <name>.
.PP
\fIresize\fR <name>
.IP
-resizes an active mapping <name>.
-
-If \-\-size (in sectors) is not specified, the size of the underlying block device is used.
-.PP
+Resizes an active mapping <name>.
+
+If \-\-size (in sectors) is not specified, the size of the
+underlying block device 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.
+.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 (created), 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
-.SH LUKS EXTENSION
+\fIcreate\fR <name> <device> (\fBOBSOLETE syntax\fR)
+.IP
+Creates a mapping with <name> backed by device <device>.
-LUKS, Linux Unified Key Setup, is a standard for hard disk encryption. It standardizes a partition header, as well as the format of the bulk data. LUKS can manage multiple passwords, that can be revoked effectively and that are protected against dictionary attacks with PBKDF2.
+\fB<options>\fR can be [\-\-hash, \-\-cipher, \-\-verify-passphrase,
+\-\-key-file, \-\-keyfile-offset, \-\-key-size, \-\-offset, \-\-skip, \-\-size,
+\-\-readonly, \-\-shared, \-\-allow-discards]
-These are valid LUKS actions:
+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.
+
+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 following are valid LUKS actions:
\fIluksFormat\fR <device> [<key file>]
.IP
-initializes a LUKS partition and sets the initial key, either via prompting or via <key file>.
-<options> can be [\-\-cipher, \-\-verify-passphrase, \-\-key-size, \-\-key-slot].
-.PP
-\fIluksOpen\fR <device> <name>
-.IP
-opens the LUKS partition <device> and sets up a mapping <name> after successful verification of the supplied key material (either via key file by \-\-key-file, or via prompting).
-<options> can be [\-\-key-file, \-\-readonly].
+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 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.
+
+\fB<options>\fR can be [\-\-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].
+
+\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
-\fIluksClose\fR <name>
+\fIopen\fR \-\-type luks <device> <name>
+.br
+\fIluksOpen\fR <device> <name> (\fBold syntax\fR)
.IP
-identical to \fIremove\fR.
+Opens the LUKS device <device> and sets up a mapping <name> after
+successful verification of the supplied passphrase.
+If the passphrase is not supplied via \-\-key-file, the command
+prompts for it interactively.
+
+The <device> parameter can be also specified by LUKS UUID in the
+format UUID=<uuid>, which uses the symlinks in /dev/disk/by-uuid.
+
+\fB<options>\fR can be [\-\-key-file, \-\-keyfile-offset,
+\-\-keyfile-size, \-\-readonly, \-\-test-passphrase,
+\-\-allow-discards, \-\-header, \-\-key-slot, \-\-master-key-file].
.PP
\fIluksSuspend\fR <name>
.IP
-suspends active device (all IO operations are frozen) and wipes encryption key from kernel. Kernel version 2.6.19 or later is required.
+Suspends an active device (all IO operations will blocked
+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.
-After that operation you have to use \fIluksResume\fR to reinstate encryption key (and resume device) or \fIluksClose\fR to remove mapped device.
+\fBWARNING:\fR never suspend the device on which the cryptsetup binary resides.
-\fBWARNING:\fR never try to suspend device where is the cryptsetup binary itself.
+\fB<options>\fR can be [\-\-header].
.PP
\fIluksResume\fR <name>
.IP
-Resumes suspended device and reinstates encryption key. You will need provide passphrase identical to \fIluksOpen\fR command (using prompting or key file).
+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]
.PP
-\fIluksAddKey\fR <device> [<new key file>]
+\fIluksAddKey\fR <device> [<key file with new key>]
.IP
-add a new key file/passphrase. An existing passphrase or key file (via \-\-key-file) must be supplied. The key file with the new material is supplied as a positional argument. <options> can be [\-\-key-file, \-\-key-slot].
+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.
+
+\fB<options>\fR can be [\-\-key-file, \-\-keyfile-offset,
+\-\-keyfile-size, \-\-new-keyfile-offset,
+\-\-new-keyfile-size, \-\-key-slot, \-\-master-key-file].
.PP
-\fIluksRemoveKey\fR <device> [<key file>]
+\fIluksRemoveKey\fR <device> [<key file with passphrase to be removed>]
.IP
-remove supplied key or key file from LUKS device
+Removes the supplied passphrase from the LUKS device. The
+passphrase to be removed can be specified interactively,
+as positional argument or via \-\-key-file.
+
+\fB<options>\fR can be [\-\-key-file, \-\-keyfile-offset,
+\-\-keyfile-size]
+
+\fBWARNING:\fR If you read the passphrase from stdin
+(without further argument or with '-' as argument
+to \-\-key-file), batch-mode (-q) will be implicitely
+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
-\fIluksKillSlot\fR <device> <key slot number>
+\fIluksChangeKey\fR <device> [<new key file>]
.IP
-wipe key with number <key slot> from LUKS device. A remaining passphrase or key file (via \-\-key-file) must be supplied. <options> can be [\-\-key-file].
+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,
+\-\-new-keyfile-size, \-\-key-slot].
.PP
-\fIluksDelKey\fR <device> <key slot number>
+\fIluksKillSlot\fR <device> <key slot number>
.IP
-identical to luksKillSlot, but deprecated action name.
+Wipe the key-slot number <key slot> from the LUKS device. 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].
+
+\fBWARNING:\fR If you read the passphrase from stdin
+(without further argument or with '-' as argument
+to \-\-key-file), batch-mode (-q) will be implicitely
+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
\fIluksUUID\fR <device>
.IP
-print UUID, if <device> has a LUKS header. No options.
+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 partition. Otherwise, false. No options.
+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.
.PP
\fIluksDump\fR <device>
.IP
-dumps the header information of a LUKS partition. No options.
+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. Beware that the master key cannot be
+changed 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 to prevent further access. Use this option carefully.
+
+In order to dump the master key, a passphrase has to be supplied,
+either interactively or via \-\-key-file.
+
+\fB<options>\fR can be [\-\-dump-master-key, \-\-key-file,
+\-\-keyfile-offset, \-\-keyfile-size].
+
+\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 binary backup of LUKS header and keyslot areas.
+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 afterwards.
+
+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.
+.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>.
-\fBWARNING:\fR Please note that with this backup file (and old passphrase knowledge) you can decrypt data even if old passphrase was wiped from real device.
+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>
-Also note that anti-forensic splitter is not used during manipulation with backup file.
+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].
.PP
-\fIluksHeaderRestore\fR <device> \-\-header-backup-file <file>
+See also section 7 of the FAQ and \fBhttp://loop-aes.sourceforge.net\fR
+for more information regarding loop-AES.
+.SH TCRYPT (TrueCrypt-compatible) EXTENSION
+cryptsetup supports mapping of TrueCrypt or tcplay 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).
+
+\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. Use the whole
+device not the system partition as the device parameter.
+
+To use hidden header (and map hidden device, if available),
+use \fB\-\-tcrypt-hidden\fR option.
+.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>.
-Restores binary backup of LUKS header and keyslot areas from specified file.
+\fB<options>\fR can be [\-\-key-file, \-\-tcrypt-hidden, \-\-tcrypt-system,
+\-\-readonly, \-\-test-passphrase].
-\fBWARNING:\fR All the keyslot areas are overwritten, only active keyslots form backup file are available after issuing this command.
+The keyfile parameter allows 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.
+.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.
-This command allows restoring header if device do not contain LUKS header or if the master key size and data offset in LUKS header on device match the backup file.
+\fB<options>\fR can be [\-\-dump-master-key, \-\-key-file, \-\-tcrypt-hidden,
+\-\-tcrypt-system].
+
+The keyfile parameter allows combination of file content with the
+passphrase and can be repeated.
.PP
+See also \fBhttp://www.truecrypt.org\fR for more information regarding
+TrueCrypt.
-For more information about LUKS, see \fBhttp://code.google.com/p/cryptsetup/wiki/Specification\fR
+Please note that cryptsetup does not use TrueCrypt code, please report
+all problems related to this compatibility extension to cryptsetup project.
+.SH MISCELLANEOUS
+.PP
+\fIrepair\fR <device>
+.IP
+Tries to repair the device metadata if possible. Currently supported only
+for LUKS device type.
-.SH OPTIONS
-.TP
-.B "\-\-hash, \-h"
-For \fIcreate\fR action specifies hash to use for password hashing.
+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.
-For \fIluksFormat\fR action specifies hash used in LUKS key setup scheme and volume key digest.
+\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.
-\fBWARNING:\fR setting hash other than \fBsha1\fR causes LUKS device incompatible with older version of cryptsetup.
+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.
-The hash string is passed to libgcrypt, so all hashes accepted by gcrypt are supported.
-Default is set during compilation, compatible values with old version of cryptsetup are
-\fB"ripemd160"\fR for \fIcreate\fR action and \fB"sha1"\fR for \fIluksFormat\fR.
+\fBNOTE:\fR This benchmark is using memory only and is only informative.
+You cannot directly predict real storage encryption speed from it.
-Use \fIcryptsetup --help\fR to show defaults.
+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 "\-\-cipher, \-c"
-set cipher specification string.
+.B "\-\-debug"
+Run in debug mode with full diagnostic logs. Debug output
+lines are always prefixed by '#'.
+.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.
-Default mode is configurable during compilation,
-you can see compiled-in default using \fIcryptsetup --help\fR.
-If not changed, the default is for plain dm-crypt and LUKS mappings
-"aes-cbc-essiv:sha256".
+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.
-For pre-2.6.10 kernels, use "aes-plain" as they don't understand
-the new cipher spec strings. To use ESSIV, use "aes-cbc-essiv:sha256".
+Values compatible with old version of cryptsetup are
+\fB"ripemd160"\fR for \fIopen \-\-type plain\fR and
+\fB"sha1"\fR for \fIluksFormat\fR.
-For XTS mode, kernel version 2.6.24 or more recent is required.
-Use "aes-xts-plain" cipher specification and set key size to 256 (or 512) bits (see \-s option).
+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 both plain dm-crypt and LUKS.
+
+For XTS mode (a possible future default), use "aes-xts-plain"
+or better "aes-xts-plain64"
+as cipher specification and 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
+kernel 2.6.33 or later. More information can be found in the FAQ.
.TP
.B "\-\-verify-passphrase, \-y"
-query for passwords twice. Useful when creating a (regular) mapping for the first time, or when running \fIluksFormat\fR.
+When interactively asking for a passphrase, ask for it twice
+and complain if both inputs do not match. Advised when creating
+a regular mapping for the first time, or when running
+\fIluksFormat\fR. Ignores on input from file or stdin.
.TP
-.B "\-\-key-file, \-d"
-use file as key material. With LUKS, key material supplied in key files via \-d are always used for existing passphrases. If you want to set a new key via a key file, you have to use a positional arg to \fIluksFormat\fR or \fIluksAddKey\fR.
+.B "\-\-key-file, \-d \fIname\fR"
+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.
-If the key file is "-", stdin will be used. This is different from how cryptsetup usually reads from stdin. See section \fBNOTES ON PASSWORD PROCESSING\fR for more information.
+With LUKS, passphrases supplied via \-\-key-file are always
+the existing passphrases requested by a command, except in
+the case of \fIluksFormat\fR where \-\-key-file is equivalent
+to the positional key file argument.
+
+If you want to set a new passphrase via key file, you have to
+use a positional argument to \fIluksAddKey\fR.
+
+See section \fBNOTES ON PASSPHRASE PROCESSING\fR for more information.
+.TP
+.B "\-\-keyfile-offset \fIvalue\fR"
+Skip \fIvalue\fR bytes at the beginning of the key file.
+Works with all commands that accepts key files.
+.TP
+.B "\-\-keyfile-size, \-l \fIvalue\fR"
+Read a maximum of \fIvalue\fR bytes from the key file.
+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.
+Works with all commands that accepts key files.
+.TP
+.B "\-\-new-keyfile-offset \fIvalue\fR"
+Skip \fIvalue\fR bytes at the start when
+adding a new passphrase from key file with
+\fIluksAddKey\fR.
+.TP
+.B "\-\-new-keyfile-size \fIvalue\fR"
+Read a maximum of \fIvalue\fR bytes when adding
+a new passphrase from key file with \fIluksAddKey\fR.
+Default is to read the whole file up to the compiled-in
+maximum length that can be queried with \-\-help.
+Supplying more than the compiled in maximum aborts the
+operation.
+When \-\-new-keyfile-offset is also given, reading starts
+after the offset.
.TP
.B "\-\-master-key-file"
-Use pre-generated master key stored in file. For \fIluksFormat\fR it allows LUKS header reformatting with the same master key (if all other parameters are the same existing encrypted data remains intact).
+Use a master key stored in a file.
+
+For \fIluksFormat\fR this
+allows creating a LUKS header with this specific
+master key. If the master key was taken from an existing
+LUKS header and all other parameters are the same,
+then the new header decrypts the data encrypted with the
+header the master key was taken from.
-For \fIluksAddKey\fR it allows adding new passphrase with only master key knowledge.
+For \fIluksAddKey\fR this allows adding a new passphrase
+without having to know an exiting one.
+
+For \fIopen\fR this allows to open the LUKS device
+without giving a passphrase.
.TP
-.B "\-\-key-slot, \-S"
-For LUKS operations that add key material, this options allows to you specify which key slot is selected for the new key. This option can be used for \fIluksFormat\fR and \fIluksAddKey\fR.
+.B "\-\-dump-master-key"
+For \fIluksDump\fR this option includes the master key in the displayed
+information. Use with care, as the master key can be used to
+bypass the passphrases, see also option \-\-master-key-file.
.TP
-.B "\-\-key-size, \-s"
-set key size in bits.
-
-Has to be a multiple of 8 bits. The key size is limited by the used cipher. See output of /proc/crypto for more information.
-Can be used for \fIcreate\fR or \fIluksFormat\fR, all other LUKS actions will use key-size specified by the LUKS header.
-Default is set during compilation, if not changed it is 256 bits.
+.B "\-\-use-random"
+.TP
+.B "\-\-use-urandom"
+For \fIluksFormat\fR these options define which kernel random number
+generator will be used to create the master key (which is a
+long-term key).
+
+See \fBNOTES ON RANDOM NUMBER GENERATORS\fR for more
+information. Use \fIcryptsetup \-\-help\fR
+to show the compiled-in default random number generator.
+
+\fBWARNING:\fR In a low-entropy situation (e.g. in an
+embedded system), both selections are problematic.
+Using /dev/urandom can lead to weak keys.
+Using /dev/random can block a long time, potentially
+forever, if not enough entropy can be harvested by
+the kernel.
+.TP
+.B "\-\-key-slot, \-S <0-7>"
+For LUKS operations that add key material, this options allows you
+to specify which key slot is selected for the new key.
+This option can be used for \fIluksFormat\fR,
+and \fIluksAddKey\fR.
+.br
+In addition, for \fIopen\fR, this option selects a
+specific key-slot to compare the passphrase against.
+If the given passphrase would only match a different key-slot,
+the operation fails.
+.TP
+.B "\-\-key-size, \-s <bits>"
+Sets key size in bits. The argument has to be a multiple of
+8. The possible key-sizes are limited by the cipher and
+mode used.
-Use \fIcryptsetup --help\fR to show defaults.
+See /proc/crypto for more information. Note that key-size
+in /proc/crypto is stated in bytes.
-For \fIluksOpen\fR this option specifies number of bits read from the key-file (default is exhaustive read from key-file).
+This option can be used for \fIopen \-\-type plain\fR or \fIluksFormat\fR.
+All other LUKS actions will use the key-size specified in the LUKS header.
+Use \fIcryptsetup \-\-help\fR to show the compiled-in defaults.
.TP
-.B "\-\-size, \-b"
-force the size of the underlying device in sectors.
-This option is only relevant for \fIcreate\fR and \fIresize\fR action.
+.B "\-\-size, \-b <number of 512 byte sectors>"
+Force the size of the underlying device in sectors of 512 bytes.
+This option is only relevant for the \fIopen\fR and \fIresize\fR
+actions.
.TP
-.B "\-\-offset, \-o"
-start offset in the backend device.
-This option is only relevant for \fIcreate\fR action.
+.B "\-\-offset, \-o <number of 512 byte sectors>"
+Start offset in the backend device in 512-byte sectors.
+This option is only relevant for the \fIopen\fR action with plain
+or loopaes device types.
.TP
-.B "\-\-skip, \-p"
-how many sectors of the encrypted data to skip at the beginning. This is different from the \-\-offset options with respect to IV calculations. Using \-\-offset will shift the IV calculation by the same negative amount. Hence, if \-\-offset \fIn\fR, sector \fIn\fR will be the first sector on the mapping with IV \fI0\fR. Using \-\-skip would have resulted in sector \fIn\fR being the first sector also, but with IV \fIn\fR.
-This option is only relevant for \fIcreate\fR action.
+.B "\-\-skip, \-p <number of 512 byte sectors>"
+How many sectors of the encrypted data to skip at the beginning.
+This option is only relevant for the \fIopen\fR action with plain
+or loopaes device types.
+
+This is different from the \-\-offset options with respect to
+the sector numbers used in IV calculation.
+Using \-\-offset will shift the IV calculation by the same negative amount.
+Hence, if \-\-offset \fIn\fR, sector \fIn\fR will get a sector
+number of \fI0\fR for the IV calculation.
+Using \-\-skip causes sector \fIn\fR to also be the first sector
+of the mapped device, but with its number for IV generation is \fIn\fR.
.TP
-.B "\-\-readonly"
+.B "\-\-readonly, \-r"
set up a read-only mapping.
.TP
-.B "\-\-iter-time, \-i"
-The number of milliseconds to spend with PBKDF2 password processing. This option is only relevant to the LUKS operations as \fIluksFormat\fR or \fIluksAddKey\fR.
+.B "\-\-shared"
+Creates an additional mapping for one common
+ciphertext device. Arbitrary mappings are supported.
+This option is only relevant for the
+\fIopen \-\-type plain\fR action. Use \-\-offset, \-\-size and \-\-skip to
+specify the mapped area.
+.TP
+.B "\-\-iter-time, \-i <number of milliseconds>"
+The number of milliseconds to spend with PBKDF2 passphrase processing.
+This option is only relevant for LUKS operations that set or change
+passphrases, such as \fIluksFormat\fR or \fIluksAddKey\fR.
+Specifying 0 as parameter selects the compiled-in default.
.TP
.B "\-\-batch-mode, \-q"
-Do not ask for confirmation. Use with care! This option is only relevant for \fIluksFormat\fR, \fIluksAddKey\fR, \fIluksRemoveKey\fR or \fIluksKillSlot\fR.
+Suppresses all confirmation questions. Use with care!
+
+If the \-y option is not specified, this option also switches off
+the passphrase verification for \fIluksFormat\fR.
.TP
-.B "\-\-timeout, \-t"
-The number of seconds to wait before timeout. This option is relevant every time a password is asked, like \fIcreate\fR, \fIluksOpen\fR, \fIluksFormat\fR or \fIluksAddKey\fR. It has no effect if used in conjunction with \-\-key-file.
+.B "\-\-timeout, \-t <number of seconds>"
+The number of seconds to wait before timeout on passphrase input
+via terminal. It is relevant every time a passphrase is asked,
+for example for \fIopen\fR, \fIluksFormat\fR or \fIluksAddKey\fR.
+It has no effect if used in conjunction with \-\-key-file.
+.br
+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.
.TP
.B "\-\-tries, \-T"
-How often the input of the passphrase shall be retried. This option is relevant every time a password is asked, like \fIcreate\fR, \fIluksOpen\fR, \fIluksFormat\fR or \fIluksAddKey\fR. The default is 3 tries.
+How often the input of the passphrase shall be retried.
+This option is relevant
+every time a passphrase is asked, for example for
+\fIopen\fR, \fIluksFormat\fR or \fIluksAddKey\fR.
+The default is 3 tries.
.TP
-.B "\-\-align-payload=\fIvalue\fR"
-Align payload at a boundary of \fIvalue\fR 512-byte sectors. This option is relevant for \fIluksFormat\fR. If your block device lives on a RAID, it is
-useful to align the filesystem at full stripe boundaries so it can take advantage of the RAID's geometry. See for instance the sunit and swidth options
-in the mkfs.xfs manual page. By default, the payload is aligned at an 8 sector (4096 byte) boundary.
-.TP
-.B "\-\-version"
-Show the version.
-
-.SH NOTES ON PASSWORD PROCESSING
-\fIFrom a file descriptor or a terminal\fR: Password processing is new-line sensitive, meaning the reading will stop after encountering \\n. It will process the read material (without newline) with the default hash or the hash given by \-\-hash. After hashing, it will be cropped to the key size given by \-s.
-
-\fIFrom stdin\fR: Reading will continue until EOF (so using e.g. /dev/random as stdin will not work), with the trailing newline stripped. After that the read data will be hashed with the default hash or the hash given by \-\-hash and the result will be cropped to the keysize given by \-s. If "plain" is used as an argument to the hash option, the input data will not be hashed.
-Instead, it will be zero padded (if shorter than the keysize) or truncated (if longer than the keysize) and used directly as the key. No warning will be given if the amount of data read from stdin is less than the keysize.
+.B "\-\-align-payload <number of 512 byte sectors>"
+Align payload at a boundary of \fIvalue\fR 512-byte sectors.
+This option is relevant for \fIluksFormat\fR.
-\fIFrom a key file\fR: It will be cropped to the size given by \-s. If there is insufficient key material in the key file, cryptsetup will quit with an error.
+If not specified, cryptsetup tries to use the topology info
+provided by kernel for the underlying device to get 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).
-If \-\-key-file=- is used for reading the key from stdin, no trailing newline is stripped from the input. Without that option, cryptsetup strips trailing newlines from stdin input.
-.SH NOTES ON PASSWORD PROCESSING FOR LUKS
-LUKS uses PBKDF2 to protect against dictionary attacks (see RFC 2898).
+For a detached LUKS header this option specifies the offset on the
+data device. See also the \-\-header option.
+.TP
+.B "\-\-uuid=\fIUUID\fR"
+Use the provided \fIUUID\fR for the \fIluksFormat\fR command
+instead of generating new one. Changes the existing UUID when
+used with the \fIluksUUID\fR command.
-LUKS will always do an exhaustive password reading. Hence, password can not be read from /dev/random, /dev/zero or any other stream that does not terminate.
+The UUID must be provided in the standard UUID format,
+e.g. 12345678-1234-1234-1234-123456789abc.
+.TP
+.B "\-\-allow-discards\fR"
+Allow the use of discard (TRIM) requests for device.
+This option is only relevant for \fIopen\fR action.
+
+\fBWARNING:\fR This command can have a negative security impact
+because it can make filesystem-level operations visible on
+the physical device. For example, information leaking
+filesystem type, used space, etc. may be extractable from
+the physical device if the discarded blocks can be located
+later. If in doubt, do no use it.
+
+A kernel version of 3.1 or later is needed. For earlier kernels
+this option is ignored.
+.TP
+.B "\-\-test-passphrase\fR"
+Do not activate device, just verify passphrase.
+This option is only relevant for \fIopen\fR action (the device
+mapping name is not mandatory if this option is used).
+.TP
+.B "\-\-header\fR <device or file storing the LUKS header>"
+Use a detached (separated) metadata device or file where the
+LUKS header is stored. This options allows to store ciphertext
+and LUKS header on different devices.
+
+This option is only relevant for LUKS devices and can be
+used with the \fIluksFormat\fR, \fIopen\fR, \fIluksSuspend\fR,
+\fIluksResume\fR, \fIstatus\fR and \fIresize\fR commands.
+
+For \fIluksFormat\fR with a file name as argument to \-\-header,
+it has to exist and be large enough to contain the LUKS header.
+See the cryptsetup FAQ for header size calculation.
+
+For other commands that change the LUKS header (e.g. \fIluksAddKey\fR),
+specify the device or file with the LUKS header directly as the
+LUKS device.
+
+If used with \fIluksFormat\fR, the \-\-align-payload option is taken
+as absolute sector alignment on ciphertext device and can be zero.
+
+\fBWARNING:\fR There is no check whether the ciphertext device specified
+actually belongs to the header given. In fact you can specify an
+arbitrary device as the ciphertext device for \fIopen\fR
+with the \-\-header option. Use with care.
+.TP
+.B "\-\-force-password\fR"
+Do not use password quality checking for new LUKS passwords.
-LUKS saves the processing options when a password is set to the respective key slot.
-Therefore, no options can be given to luksOpen.
-For any password creation action (luksAddKey, or luksFormat), the user may specify how much the time the password processing should consume.
-Increasing the time will lead to a more secure password, but also will take luksOpen longer to complete. The default setting of one second is sufficient for good security.
-.SH INCOHERENT BEHAVIOUR FOR INVALID PASSWORDS/KEYS
-LUKS checks for a valid password or key when an encrypted partition is unlocked. Thus the luksOpen action fails with invalid password or key, contrary to the plain dm-crypt create action.
+This option applies only to \fIluksFormat\fR, \fIluksAddKey\fR and
+\fIluksChangeKey\fR and is ignored if cryptsetup is built without
+password quality checking support.
-Please also be sure that you are using the same keyboard and language setting as during device format.
+For more info about password quality check, see manual page
+for \fBpwquality.conf(5)\fR.
+.TP
+.B "\-\-version"
+Show the program version.
+.TP
+.B "\-\-usage"
+Show short option help.
+.TP
+.B "\-\-help, \-?"
+Show help text and default parameters.
+.SH RETURN CODES
+Cryptsetup returns 0 on success and a non-zero value on error.
+
+Error codes are: 1 wrong parameters, 2 no permission (bad passphrase),
+3 out of memory, 4 wrong device specified, 5 device already exists
+or device is busy.
+.SH NOTES ON PASSPHRASE PROCESSING FOR PLAIN MODE
+Note that no iterated hashing or salting is done in plain mode.
+If hashing is done, it is a single direct hash. This means that
+low-entropy passphrases are easy to attack in plain mode.
+
+\fBFrom a terminal\fR: The passphrase is read until the
+first newline, i.e. '\\n'.
+The input without the newline character is processed with
+the default hash or the hash specified with \-\-hash.
+The has result will be truncated to the key size
+of the used cipher, or the size specified with \-s.
+
+\fBFrom stdin\fR: Reading will continue until a newline (or until
+the maximum input size is reached), with the trailing newline
+stripped. The maximum input size is defined by the same
+compiled-in default as for the maximum key file size and can
+be overwritten using \-\-keyfile-size option.
+
+The data read will be hashed with the default hash
+or the hash specified with \-\-hash.
+The has result will be truncated to the key size
+of the used cipher, or the size specified with \-s.
+
+Note that if \-\-key-file=- is used for reading the key
+from stdin, trailing newlines are not stripped from the input.
+
+If "plain" is used as argument to \-\-hash, the input
+data will not be hashed. Instead, it will be zero padded (if
+shorter than the key size) or truncated (if longer than the
+key size) and used directly as the binary key. This is useful for
+directly specifying a binary key.
+No warning will be given if the amount of data read from stdin is
+less than the key size.
+
+\fBFrom a key file\fR: It will be truncated to the
+key size of the used cipher or the size given by \-s
+and directly used as binary key.
+if the key file is shorter than the key, cryptsetup
+will quit with an error.
+
+.SH NOTES ON PASSPHRASE PROCESSING FOR LUKS
+LUKS uses PBKDF2 to protect against dictionary attacks
+and to give some protection to low-entropy passphrases
+(see RFC 2898 and the cryptsetup FAQ).
+
+\fBFrom a terminal\fR: The passphrase is read until the
+first newline and then processed by PBKDF2 without
+the newline character.
+
+\fBFrom stdin\fR:
+LUKS will read passphrases from stdin up to the
+first newline character or the compiled-in
+maximum key file length. If \-\-keyfile-size is
+given, it is ignored.
+
+\fBFrom key file\fR:
+The complete keyfile is read up to the compiled-in
+maximum size. Newline characters do not terminate the
+input. The \-\-keyfile-size option can be used to limit
+what is read.
+
+\fBPassphrase processing\fR:
+Whenever a passphrase is added to a LUKS header (luksAddKey, luksFormat),
+the user may specify how much the time the passphrase processing
+should consume. The time is used to determine the iteration count
+for PBKDF2 and higher times will offer better protection for
+low-entropy passphrases, but open will take longer to
+complete. For passphrases that have entropy higher than the
+used key length, higher iteration times will not increase security.
+
+The default setting of one second is sufficient for most
+practical cases. The only exception is a low-entropy
+passphrase used on a slow device.
+.SH INCOHERENT BEHAVIOR FOR INVALID PASSPHRASES/KEYS
+LUKS checks for a valid passphrase when an encrypted partition
+is unlocked. The behavior of plain dm-crypt is different.
+It will always decrypt with the passphrase given. If the
+given passphrase is wrong, the device mapped by plain
+dm-crypt will essentially still contain encrypted data and
+will be unreadable.
.SH NOTES ON SUPPORTED CIPHERS, MODES, HASHES AND KEY SIZES
-The available combinations of ciphers, modes, hashes and key sizes depend on kernel support. See /proc/crypto for a list of available options. You might need to load additional kernel crypto modules in order to get more options.
-
-For \-\-hash option all algorithms supported by gcrypt library are available.
-.SH NOTES ON PASSWORDS
-Mathematics can't be bribed. Make sure you keep your passwords safe. There are a few nice tricks for constructing a fallback, when suddenly out of (or after being) blue, your brain refuses to cooperate. These fallbacks are possible with LUKS, as it's only possible with LUKS to have multiple passwords.
-.SH AUTHORS
-cryptsetup is written by Christophe Saout <christophe@saout.de>
-.br
-LUKS extensions, and man page by Clemens Fruhwirth <clemens@endorphin.org>
-.SH "COMPATABILITY WITH OLD SUSE TWOFISH PARTITIONS"
-To read images created with SuSE Linux 9.2's loop_fish2 use \-\-cipher
-twofish-cbc-null \-s 256 \-h sha512, for images created with even
-older SuSE Linux use \-\-cipher twofish-cbc-null \-s 192 \-h
-ripemd160:20
-
+The available combinations of ciphers, modes, hashes and key sizes
+depend on kernel support. See /proc/crypto for a list of available
+options. You might need to load additional kernel crypto modules
+in order to get more options.
+
+For the \-\-hash option, if the crypto backend is libgcrypt,
+then all algorithms supported by the gcrypt library are available.
+For other crypto backends some algorithms may be missing.
+.SH NOTES ON PASSPHRASES
+Mathematics can't be bribed. Make sure you keep your passphrases safe.
+There are a few nice tricks for constructing a fallback, when suddenly
+out of the blue, your brain refuses to cooperate.
+These fallbacks need LUKS, as it's only possible with LUKS
+to have multiple passphrases. Still, if your attacker model does
+not prevent it, storing your passphrase in a sealed envelope somewhere
+may be a good idea as well.
+.SH NOTES ON RANDOM NUMBER GENERATORS
+Random Number Generators (RNG) used in cryptsetup are always the
+kernel RNGs without any modifications or additions to data stream
+produced.
+
+There are two types of randomness cryptsetup/LUKS needs. One type
+(which always uses /dev/urandom) is used for salts, the AF splitter
+and for wiping deleted keyslots.
+
+The second type is used for the volume (master) key. You can switch
+between using /dev/random and /dev/urandom here, see
+\fP\-\-use-random\fR and \fP\-\-use-urandom\fR
+options. Using /dev/random on a system without enough entropy sources
+can cause \fPluksFormat\fR to block until the requested amount of
+random data is gathered. In a low-entropy situation (embedded system),
+this can take a very long time and potentially forever. At the same
+time, using /dev/urandom in a low-entropy situation will
+produce low-quality keys. This is a serious problem, but solving
+it is out of scope for a mere man-page.
+See \fPurandom(4)\fR for more information.
+.SH NOTES ON LOOPBACK DEVICE USE
+Cryptsetup is usually used directly on a block device (disk
+partition or LVM volume). However, if the device argument is a
+file, cryptsetup tries to allocate a loopback device
+and map it into this file. This mode requires Linux kernel 2.6.25
+or more recent which supports the loop autoclear flag (loop device is
+cleared on last close automatically). Of course, you can
+always map a file to a loop-device manually. See the
+cryptsetup FAQ for an example.
+
+When device mapping is active, you can see the loop backing file in
+the status command output. Also see losetup(8).
.SH DEPRECATED ACTIONS
.PP
-\fIreload\fR <name> <device>
-.IP
-modifies an active mapping <name>. Same options as for
-create.
-.B WARNING:
-Do not use this for LUKS devices, as the semantics
-are identical to the create action, which are totally incompatible
-with the LUKS key setup.
-
-This action is deprected because it proved to be rarely useful. It is
-uncommon to change the underlying device, key, or offset on the
-fly. In case, you really want to do this, you certainly know what you
-are doing and then you are probably better off with the swiss knive
-tool for device mapper, namely dmsetup. It provides you with the same
-functionality, see dmsetup reload.
+The \fIreload\fR action is no longer supported.
+Please use \fIdmsetup(8)\fR if you need to
+directly manipulate with the device mapping table.
.PP
-\fIluksDelKey\fR <device> <key slot number>
-.IP
-identical to luksKillSlot, but deprecated action name. This option was
-renamed, as we introduced luksRemoveKey, a softer method for disabling
-password slots. To make a clear distinction that luksDelKey was more brutal than luksRemoveKey
+The \fIluksDelKey\fR was replaced with \fIluksKillSlot\fR.
.PP
-\fI\-\-non-exclusive\fR
-.IP
-This option is ignored. Non-exclusive access to the same block device
-can cause data corruption thus this mode is no longer supported by cryptsetup.
-
-.SH "REPORTING BUGS"
-Report bugs to <dm-crypt@saout.de>.
+.SH REPORTING BUGS
+Report bugs, including ones in the documentation, on
+the cryptsetup mailing list at <dm-crypt@saout.de>
+or in the 'Issues' section on LUKS website.
+Please attach the output of the failed command with the
+\-\-debug option added.
+.SH AUTHORS
+cryptsetup originally written by Christophe Saout <christophe@saout.de>
+.br
+The LUKS extensions and original man page were written by
+Clemens Fruhwirth <clemens@endorphin.org>.
+.br
+Man page extensions by Milan Broz <gmazyland@gmail.com>.
+.br
+Man page rewrite and extension by Arno Wagner <arno@wagner.name>.
.SH COPYRIGHT
Copyright \(co 2004 Christophe Saout
.br
Copyright \(co 2004-2006 Clemens Fruhwirth
.br
-Copyright \(co 2009 Red Hat, Inc.
+Copyright \(co 2009-2012 Red Hat, Inc.
+.br
+Copyright \(co 2009-2012 Milan Broz
+.br
+Copyright \(co 2012 Arno Wagner
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-.SH "SEE ALSO"
+.SH SEE ALSO
+The LUKS website at \fBhttp://code.google.com/p/cryptsetup/\fR
-dm-crypt website, \fBhttp://www.saout.de/misc/dm-crypt/\fR
+The cryptsetup FAQ, contained in the distribution package and
+online at
+\fBhttp://code.google.com/p/cryptsetup/wiki/FrequentlyAskedQuestions\fR
-LUKS website, \fBhttp://code.google.com/p/cryptsetup/\fR
+The cryptsetup mailing list and list archive, see FAQ entry 1.6.
-dm-crypt TWiki, \fBhttp://www.saout.de/tikiwiki/tiki-index.php\fR
+The LUKS on-disk format specification available at
+\fBhttp://code.google.com/p/cryptsetup/wiki/Specification\fR
projects / platform / upstream / cryptsetup.git / blobdiff