1CRYPTSETUP-LUKSFORMAT(8) Maintenance Commands CRYPTSETUP-LUKSFORMAT(8)
2
6 cryptsetup-luksFormat - initialize a LUKS partition and set the initial
7 passphrase
8
10 cryptsetup luksFormat [<options>] <device> [<key file>]
11
13 Initializes a LUKS partition and sets the initial passphrase (for
14 key-slot 0), either via prompting or via <key file>. Note that if the
15 second argument is present, then the passphrase is taken from the file
16 given there, without the need to use the --key-file option. Also note
17 that for both forms of reading the passphrase from a file you can give
18 '-' as file name, which results in the passphrase being read from stdin
19 and the safety-question being skipped.
20 You cannot call luksFormat on a device or filesystem that is mapped or
22 in use, e.g., mounted filesystem, used in LVM, active RAID member, etc.
23 The device or filesystem has to be un-mounted in order to call
24 luksFormat.
25 To use specific version of LUKS format, use --type luks1 or type luks2.
27 <options> can be [--hash, --cipher, --verify-passphrase, --key-size,
29 --key-slot, --key-file (takes precedence over optional second
30 argument), --keyfile-offset, --keyfile-size, --use-random,
31 --use-urandom, --uuid, --volume-key-file, --iter-time, --header,
32 --pbkdf-force-iterations, --force-password, --disable-locks, --timeout,
33 --type, --offset, --align-payload (deprecated)].
34 For LUKS2, additional <options> can be [--integrity,
36 --integrity-no-wipe, --sector-size, --label, --subsystem, --pbkdf,
37 --pbkdf-memory, --pbkdf-parallel, --disable-locks, --disable-keyring,
38 --luks2-metadata-size, --luks2-keyslots-size, --keyslot-cipher,
39 --keyslot-key-size, --integrity-legacy-padding].
40 WARNING: Doing a luksFormat on an existing LUKS container will make all
42 data in the old container permanently irretrievable unless you have a
43 header backup.
44
46 --type <device-type>
47 Specifies required device type, for more info read BASIC ACTIONS
48 section in cryptsetup(8).
49 --hash, -h <hash-spec>
51 Specifies the hash used in the LUKS key setup scheme and volume key
52 digest. The specified hash is used for PBKDF2 and AF splitter.
53 The hash algorithm must provide at least 160 bits of output. Do not
55 use a non-crypto hash like xxhash as this breaks security. Use
56 cryptsetup --help to show the defaults.
57 --cipher, -c <cipher-spec>
59 Set the cipher specification string.
60 cryptsetup --help shows the compiled-in defaults.
62 If a hash is part of the cipher specification, then it is used as
64 part of the IV generation. For example, ESSIV needs a hash
65 function, while "plain64" does not and hence none is specified.
66 For XTS mode you can optionally set a key size of 512 bits with the
68 -s option. Key size for XTS mode is twice that for other modes for
69 the same security level.
70 --verify-passphrase, -y
72 When interactively asking for a passphrase, ask for it twice and
73 complain if both inputs do not match. Ignored on input from file or
74 stdin.
75 --key-file, -d name
77 Read the passphrase from file.
78 If the name given is "-", then the passphrase will be read from
80 stdin. In this case, reading will not stop at newline characters.
81 See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8) for
83 more information.
84 --keyfile-offset value
86 Skip value bytes at the beginning of the key file.
87 --keyfile-size, -l value
89 Read a maximum of value bytes from the key file. The default is to
90 read the whole file up to the compiled-in maximum that can be
91 queried with --help. Supplying more data than the compiled-in
92 maximum aborts the operation.
93 This option is useful to cut trailing newlines, for example. If
95 --keyfile-offset is also given, the size count starts after the
96 offset.
97 --volume-key-file, --master-key-file (OBSOLETE alias)
99 Use a volume key stored in a file. WARNING: If you create your own
100 volume key, you need to make sure to do it right. Otherwise, you
101 can end up with a low-entropy or otherwise partially predictable
102 volume key which will compromise security.
103 --use-random, --use-urandom
105 For luksFormat these options define which kernel random number
106 generator will be used to create the volume key (which is a
107 long-term key).
108 See NOTES ON RANDOM NUMBER GENERATORS in cryptsetup(8) for more
110 information. Use cryptsetup --help to show the compiled-in default
111 random number generator.
112 WARNING: In a low-entropy situation (e.g. in an embedded system)
114 and older kernels, both selections are problematic. Using
115 /dev/urandom can lead to weak keys. Using /dev/random can block a
116 long time, potentially forever, if not enough entropy can be
117 harvested by the kernel.
118 --key-slot, -S <0-N>
120 For LUKS operations that add key material, this option allows you
121 to specify which key slot is selected for the new key.
122 The maximum number of key slots depends on the LUKS version. LUKS1
124 can have up to 8 key slots. LUKS2 can have up to 32 key slots based
125 on key slot area size and key size, but a valid key slot ID can
126 always be between 0 and 31 for LUKS2.
127 --key-size, -s bits
129 Sets key size in bits. The argument has to be a multiple of 8. The
130 possible key-sizes are limited by the cipher and mode used.
131 See /proc/crypto for more information. Note that key-size in
133 /proc/crypto is stated in bytes.
134 This option can be used for open --type plain or luksFormat. All
136 other LUKS actions will use the key-size specified in the LUKS
137 header. Use cryptsetup --help to show the compiled-in defaults.
138 --offset, -o <number of 512 byte sectors>
140 Start offset in the backend device in 512-byte sectors.
141 The --offset option sets the data offset (payload) of data device
143 and must be aligned to 4096-byte sectors (must be multiple of 8).
144 This option cannot be combined with --align-payload option.
145 --pbkdf <PBKDF spec>
147 Set Password-Based Key Derivation Function (PBKDF) algorithm for
148 LUKS keyslot. The PBKDF can be: pbkdf2 (for PBKDF2 according to
149 RFC2898), argon2i for Argon2i or argon2id for Argon2id (see Argon2
150 <https://www.cryptolux.org/index.php/Argon2> for more info).
151 For LUKS1, only PBKDF2 is accepted (no need to use this option).
153 The default PBKDF for LUKS2 is set during compilation time and is
154 available in cryptsetup --help output.
155 A PBKDF is used for increasing dictionary and brute-force attack
157 cost for keyslot passwords. The parameters can be time, memory and
158 parallel cost.
159 For PBKDF2, only time cost (number of iterations) applies. For
161 Argon2i/id, there is also memory cost (memory required during the
162 process of key derivation) and parallel cost (number of threads
163 that run in parallel during the key derivation.
164 Note that increasing memory cost also increases time, so the final
166 parameter values are measured by a benchmark. The benchmark tries
167 to find iteration time (--iter-time) with required memory cost
168 --pbkdf-memory. If it is not possible, the memory cost is decreased
169 as well. The parallel cost --pbkdf-parallel is constant and is
170 checked against available CPU cores.
171 You can see all PBKDF parameters for particular LUKS2 keyslot with
173 cryptsetup-luksDump(8) command.
174 NOTE: If you do not want to use benchmark and want to specify all
176 parameters directly, use --pbkdf-force-iterations with
177 --pbkdf-memory and --pbkdf-parallel. This will override the values
178 without benchmarking. Note it can cause extremely long unlocking
179 time. Use only in specific cases, for example, if you know that the
180 formatted device will be used on some small embedded system.
181 MINIMAL AND MAXIMAL PBKDF COSTS: For PBKDF2, the minimum iteration
183 count is 1000 and maximum is 4294967295 (maximum for 32bit unsigned
184 integer). Memory and parallel costs are unused for PBKDF2. For
185 Argon2i and Argon2id, minimum iteration count (CPU cost) is 4 and
186 maximum is 4294967295 (maximum for 32bit unsigned integer). Minimum
187 memory cost is 32 KiB and maximum is 4 GiB. (Limited by addressable
188 memory on some CPU platforms.) If the memory cost parameter is
189 benchmarked (not specified by a parameter) it is always in range
190 from 64 MiB to 1 GiB. The parallel cost minimum is 1 and maximum 4
191 (if enough CPUs cores are available, otherwise it is decreased).
192 --iter-time, -i <number of milliseconds>
194 The number of milliseconds to spend with PBKDF passphrase
195 processing. Specifying 0 as parameter selects the compiled-in
196 default.
197 --pbkdf-memory <number>
199 Set the memory cost for PBKDF (for Argon2i/id the number represents
200 kilobytes). Note that it is maximal value, PBKDF benchmark or
201 available physical memory can decrease it. This option is not
202 available for PBKDF2.
203 --pbkdf-parallel <number>
205 Set the parallel cost for PBKDF (number of threads, up to 4). Note
206 that it is maximal value, it is decreased automatically if CPU
207 online count is lower. This option is not available for PBKDF2.
208 --pbkdf-force-iterations <num>
210 Avoid PBKDF benchmark and set time cost (iterations) directly. It
211 can be used for LUKS/LUKS2 device only. See --pbkdf option for more
212 info.
213 --progress-frequency seconds
215 Print separate line every seconds with wipe progress.
216 --progress-json
218 Prints progress data in JSON format suitable mostly for machine
219 processing. It prints separate line every half second (or based on
220 --progress-frequency value). The JSON output looks as follows
221 during progress (except it’s compact single line):
222 {
224 "device":"/dev/sda" // backing device or file
225 "device_bytes":"8192", // bytes of I/O so far
226 "device_size":"44040192", // total bytes of I/O to go
227 "speed":"126877696", // calculated speed in bytes per second (based on progress so far)
228 "eta_ms":"2520012" // estimated time to finish an operation in milliseconds
229 "time_ms":"5561235" // total time spent in IO operation in milliseconds
230 }
231 Note on numbers in JSON output: Due to JSON parsers limitations all
233 numbers are represented in a string format due to need of full
234 64bit unsigned integers.
235 --timeout, -t <number of seconds>
237 The number of seconds to wait before timeout on passphrase input
238 via terminal. It is relevant every time a passphrase is asked. It
239 has no effect if used in conjunction with --key-file.
240 This option is useful when the system should not stall if the user
242 does not input a passphrase, e.g. during boot. The default is a
243 value of 0 seconds, which means to wait forever.
244 --align-payload <number of 512 byte sectors>
246 Align payload at a boundary of value 512-byte sectors.
247 If not specified, cryptsetup tries to use the topology info
249 provided by the kernel for the underlying device to get the optimal
250 alignment. If not available (or the calculated value is a multiple
251 of the default) data is by default aligned to a 1MiB boundary (i.e.
252 2048 512-byte sectors).
253 For a detached LUKS header, this option specifies the offset on the
255 data device. See also the --header option.
256 WARNING: This option is DEPRECATED and has often unexpected impact
258 to the data offset and keyslot area size (for LUKS2) due to the
259 complex rounding. For fixed data device offset use --offset option
260 instead.
261 --uuid <UUID>
263 Use the provided UUID for the luksFormat command instead of
264 generating a new one. Changes the existing UUID when used with the
265 luksUUID command.
266 The UUID must be provided in the standard UUID format, e.g.
268 12345678-1234-1234-1234-123456789abc.
269 --header <device or file storing the LUKS header>
271 Use a detached (separated) metadata device or file where the LUKS
272 header is stored. This option allows one to store ciphertext and
273 LUKS header on different devices.
274 With a file name as the argument to --header, the file will be
276 automatically created if it does not exist. See the cryptsetup FAQ
277 for header size calculation.
278 The --align-payload option is taken as absolute sector alignment on
280 ciphertext device and can be zero.
281 --force-password
283 Do not use password quality checking for new LUKS passwords.
284 This option is ignored if cryptsetup is built without password
286 quality checking support.
287 For more info about password quality check, see the manual page for
289 pwquality.conf(5) and passwdqc.conf(5).
290 --disable-locks
292 Disable lock protection for metadata on disk. This option is valid
293 only for LUKS2 and ignored for other formats.
294 WARNING: Do not use this option unless you run cryptsetup in a
296 restricted environment where locking is impossible to perform
297 (where /run directory cannot be used).
298 --disable-keyring
300 Do not load volume key in kernel keyring and store it directly in
301 the dm-crypt target instead. This option is supported only for the
302 LUKS2 type.
303 --sector-size bytes
305 Set sector size for use with disk encryption. It must be power of
306 two and in range 512 - 4096 bytes. This option is available only
307 with LUKS2 format.
308 For LUKS2 devices it’s established based on parameters provided by
310 underlying data device. For native 4K block devices it’s 4096
311 bytes. For 4K/512e (4K physical sector size with 512 bytes
312 emulation) it’s 4096 bytes. For drives reporting only 512 bytes
313 block size it remains 512 bytes. If data device is regular file put
314 in filesystem it’s 4096 bytes.
315 Note that if sector size is higher than underlying device hardware
317 sector and there is not integrity protection that uses data
318 journal, using this option can increase risk on incomplete sector
319 writes during a power fail.
320 If used together with --integrity option and dm-integrity journal,
322 the atomicity of writes is guaranteed in all cases (but it cost
323 write performance - data has to be written twice).
324 Increasing sector size from 512 bytes to 4096 bytes can provide
326 better performance on most of the modern storage devices and also
327 with some hw encryption accelerators.
328 --label <LABEL> --subsystem <SUBSYSTEM>
330 Set label and subsystem description for LUKS2 device. The label and
331 subsystem are optional fields and can be later used in udev scripts
332 for triggering user actions once the device marked by these labels
333 is detected.
334 --integrity <integrity algorithm>
336 Specify integrity algorithm to be used for authenticated disk
337 encryption in LUKS2.
338 WARNING: This extension is EXPERIMENTAL and requires dm-integrity
340 kernel target (available since kernel version 4.12). For native
341 AEAD modes, also enable "User-space interface for AEAD cipher
342 algorithms" in "Cryptographic API" section
343 (CONFIG_CRYPTO_USER_API_AEAD .config option).
344 For more info, see AUTHENTICATED DISK ENCRYPTION section in
346 cryptsetup(8).
347 --integrity-legacy-padding
349 Use inefficient legacy padding.
350 WARNING: Do not use this option until you need compatibility with
352 specific old kernel.
353 --luks2-metadata-size <size>
355 This option can be used to enlarge the LUKS2 metadata (JSON) area.
356 The size includes 4096 bytes for binary metadata (usable JSON area
357 is smaller of the binary area). According to LUKS2 specification,
358 only these values are valid: 16, 32, 64, 128, 256, 512, 1024, 2048
359 and 4096 kB The <size> can be specified with unit suffix (for
360 example 128k).
361 --luks2-keyslots-size <size>
363 This option can be used to set specific size of the LUKS2 binary
364 keyslot area (key material is encrypted there). The value must be
365 aligned to multiple of 4096 bytes with maximum size 128MB. The
366 <size> can be specified with unit suffix (for example 128k).
367 --keyslot-cipher <cipher-spec>
369 This option can be used to set specific cipher encryption for the
370 LUKS2 keyslot area.
371 --keyslot-key-size <bits>
373 This option can be used to set specific key size for the LUKS2
374 keyslot area.
375 --integrity-no-wipe
377 Skip wiping of device authentication (integrity) tags. If you skip
378 this step, sectors will report invalid integrity tag until an
379 application write to the sector.
380 NOTE: Even some writes to the device can fail if the write is not
382 aligned to page size and page-cache initiates read of a sector with
383 invalid integrity tag.
384 --batch-mode, -q
386 Suppresses all confirmation questions. Use with care!
387 If the --verify-passphrase option is not specified, this option
389 also switches off the passphrase verification.
390 --debug or --debug-json
392 Run in debug mode with full diagnostic logs. Debug output lines are
393 always prefixed by #.
394 If --debug-json is used, additional LUKS2 JSON data structures are
396 printed.
397 --version, -V
399 Show the program version.
400 --usage
402 Show short option help.
403 --help, -?
405 Show help text and default parameters.
406
408 Report bugs at cryptsetup mailing list <cryptsetup@lists.linux.dev> or
409 in Issues project section
410 <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.
411 Please attach output of the failed command with --debug option added.
413
415 Cryptsetup FAQ
416 <https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>
417 cryptsetup(8), integritysetup(8) and veritysetup(8)
419
421 Part of cryptsetup project <https://gitlab.com/cryptsetup/cryptsetup/>.
422cryptsetup 2.6.1 2023-02-10 CRYPTSETUP-LUKSFORMAT(8)