1CRYPTSETUP-LUKSADDKEY(8) Maintenance Commands CRYPTSETUP-LUKSADDKEY(8)
2
6 cryptsetup-luksAddKey - add a new passphrase
7
9 cryptsetup luksAddKey [<options>] <device> [<key file with new key>]
10
12 Adds a new passphrase. An existing passphrase must be supplied
13 interactively or via --key-file. The new passphrase to be added can be
14 specified interactively or read from the file given as the positional
15 argument.
16 NOTE: with --unbound option the action creates new unbound LUKS2
18 keyslot. The keyslot cannot be used for device activation. If you don’t
19 pass new key via --volume-key-file option, new random key is generated.
20 Existing passphrase for any active keyslot is not required.
21 NOTE: some parameters are effective only if used with LUKS2 format that
23 supports per-keyslot parameters. For LUKS1, PBKDF type and hash
24 algorithm is always the same for all keyslots.
25 <options> can be [--key-file, --keyfile-offset, --keyfile-size,
27 --new-keyfile-offset, --new-keyfile-size, --key-slot,
28 --volume-key-file, --force-password, --hash, --header, --disable-locks,
29 --iter-time, --pbkdf, --pbkdf-force-iterations, --pbkdf-memory,
30 --pbkdf-parallel, --unbound, --type, --keyslot-cipher,
31 --keyslot-key-size, --key-size, --timeout, --verify-passphrase].
32
34 --type <device-type>
35 Specifies required device type, for more info read BASIC ACTIONS
36 section in cryptsetup(8).
37 --hash, -h <hash-spec>
39 The specified hash is used for PBKDF2 and AF splitter.
40 --verify-passphrase, -y
42 When interactively asking for a passphrase, ask for it twice and
43 complain if both inputs do not match. Ignored on input from file or
44 stdin.
45 --key-file, -d name
47 Read the passphrase from file.
48 If the name given is "-", then the passphrase will be read from
50 stdin. In this case, reading will not stop at newline characters.
51 With LUKS, the passphrase supplied via --key-file is always the
53 existing passphrase requested by a command, except in the case of
54 luksFormat where --key-file is equivalent to the positional key
55 file argument.
56 If you want to set a new passphrase via key file, you have to use a
58 positional argument to luksAddKey.
59 See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8) for
61 more information.
62 --keyfile-offset value
64 Skip value bytes at the beginning of the key file.
65 --keyfile-size, -l value
67 Read a maximum of value bytes from the key file. The default is to
68 read the whole file up to the compiled-in maximum that can be
69 queried with --help. Supplying more data than the compiled-in
70 maximum aborts the operation.
71 This option is useful to cut trailing newlines, for example. If
73 --keyfile-offset is also given, the size count starts after the
74 offset.
75 --new-keyfile-offset value
77 Skip value bytes at the start when adding a new passphrase from key
78 file with luksAddKey.
79 --new-keyfile-size value
81 Read a maximum of value bytes when adding a new passphrase from key
82 file with luksAddKey. The default is to read the whole file up to
83 the compiled-in maximum length that can be queried with --help.
84 Supplying more than the compiled in maximum aborts the operation.
85 When --new-keyfile-offset is also given, reading starts after the
86 offset.
87 --volume-key-file, --master-key-file (OBSOLETE alias)
89 Use a volume key stored in a file. For luksAddKey this allows
90 adding a new passphrase without having to know an existing one.
91 WARNING: If you create your own volume key, you need to make sure
92 to do it right. Otherwise, you can end up with a low-entropy or
93 otherwise partially predictable volume key which will compromise
94 security.
95 --key-slot, -S <0-N>
97 For LUKS operations that add key material, this option allows you
98 to specify which key slot is selected for the new key.
99 The maximum number of key slots depends on the LUKS version. LUKS1
101 can have up to 8 key slots. LUKS2 can have up to 32 key slots based
102 on key slot area size and key size, but a valid key slot ID can
103 always be between 0 and 31 for LUKS2.
104 --key-size, -s bits
106 Sets key size in bits. The argument has to be a multiple of 8. The
107 possible key-sizes are limited by the cipher and mode used.
108 See /proc/crypto for more information. Note that key-size in
110 /proc/crypto is stated in bytes.
111 This option can be used for open --type plain or luksFormat. All
113 other LUKS actions will use the key-size specified in the LUKS
114 header. Use cryptsetup --help to show the compiled-in defaults.
115 --pbkdf <PBKDF spec>
117 Set Password-Based Key Derivation Function (PBKDF) algorithm for
118 LUKS keyslot. The PBKDF can be: pbkdf2 (for PBKDF2 according to
119 RFC2898), argon2i for Argon2i or argon2id for Argon2id (see Argon2
120 <https://www.cryptolux.org/index.php/Argon2> for more info).
121 For LUKS1, only PBKDF2 is accepted (no need to use this option).
123 The default PBKDF for LUKS2 is set during compilation time and is
124 available in cryptsetup --help output.
125 A PBKDF is used for increasing dictionary and brute-force attack
127 cost for keyslot passwords. The parameters can be time, memory and
128 parallel cost.
129 For PBKDF2, only time cost (number of iterations) applies. For
131 Argon2i/id, there is also memory cost (memory required during the
132 process of key derivation) and parallel cost (number of threads
133 that run in parallel during the key derivation.
134 Note that increasing memory cost also increases time, so the final
136 parameter values are measured by a benchmark. The benchmark tries
137 to find iteration time (--iter-time) with required memory cost
138 --pbkdf-memory. If it is not possible, the memory cost is decreased
139 as well. The parallel cost --pbkdf-parallel is constant and is
140 checked against available CPU cores.
141 You can see all PBKDF parameters for particular LUKS2 keyslot with
143 cryptsetup-luksDump(8) command.
144 NOTE: If you do not want to use benchmark and want to specify all
146 parameters directly, use --pbkdf-force-iterations with
147 --pbkdf-memory and --pbkdf-parallel. This will override the values
148 without benchmarking. Note it can cause extremely long unlocking
149 time. Use only in specific cases, for example, if you know that the
150 formatted device will be used on some small embedded system.
151 MINIMAL AND MAXIMAL PBKDF COSTS: For PBKDF2, the minimum iteration
153 count is 1000 and maximum is 4294967295 (maximum for 32bit unsigned
154 integer). Memory and parallel costs are unused for PBKDF2. For
155 Argon2i and Argon2id, minimum iteration count (CPU cost) is 4 and
156 maximum is 4294967295 (maximum for 32bit unsigned integer). Minimum
157 memory cost is 32 KiB and maximum is 4 GiB. (Limited by addressable
158 memory on some CPU platforms.) If the memory cost parameter is
159 benchmarked (not specified by a parameter) it is always in range
160 from 64 MiB to 1 GiB. The parallel cost minimum is 1 and maximum 4
161 (if enough CPUs cores are available, otherwise it is decreased).
162 --iter-time, -i <number of milliseconds>
164 The number of milliseconds to spend with PBKDF passphrase
165 processing. Specifying 0 as parameter selects the compiled-in
166 default.
167 --pbkdf-memory <number>
169 Set the memory cost for PBKDF (for Argon2i/id the number represents
170 kilobytes). Note that it is maximal value, PBKDF benchmark or
171 available physical memory can decrease it. This option is not
172 available for PBKDF2.
173 --pbkdf-parallel <number>
175 Set the parallel cost for PBKDF (number of threads, up to 4). Note
176 that it is maximal value, it is decreased automatically if CPU
177 online count is lower. This option is not available for PBKDF2.
178 --pbkdf-force-iterations <num>
180 Avoid PBKDF benchmark and set time cost (iterations) directly. It
181 can be used for LUKS/LUKS2 device only. See --pbkdf option for more
182 info.
183 --timeout, -t <number of seconds>
185 The number of seconds to wait before timeout on passphrase input
186 via terminal. It is relevant every time a passphrase is asked. It
187 has no effect if used in conjunction with --key-file.
188 This option is useful when the system should not stall if the user
190 does not input a passphrase, e.g. during boot. The default is a
191 value of 0 seconds, which means to wait forever.
192 --header <device or file storing the LUKS header>
194 Use a detached (separated) metadata device or file where the LUKS
195 header is stored. This option allows one to store ciphertext and
196 LUKS header on different devices.
197 For commands that change the LUKS header (e.g. luksAddKey), specify
199 the device or file with the LUKS header directly as the LUKS
200 device.
201 --force-password
203 Do not use password quality checking for new LUKS passwords.
204 This option is ignored if cryptsetup is built without password
206 quality checking support.
207 For more info about password quality check, see the manual page for
209 pwquality.conf(5) and passwdqc.conf(5).
210 --disable-locks
212 Disable lock protection for metadata on disk. This option is valid
213 only for LUKS2 and ignored for other formats.
214 WARNING: Do not use this option unless you run cryptsetup in a
216 restricted environment where locking is impossible to perform
217 (where /run directory cannot be used).
218 --keyslot-cipher <cipher-spec>
220 This option can be used to set specific cipher encryption for the
221 LUKS2 keyslot area.
222 --keyslot-key-size <bits>
224 This option can be used to set specific key size for the LUKS2
225 keyslot area.
226 --unbound
228 Creates new or dumps existing LUKS2 unbound keyslot.
229 --batch-mode, -q
231 Suppresses all confirmation questions. Use with care!
232 If the --verify-passphrase option is not specified, this option
234 also switches off the passphrase verification.
235 --debug or --debug-json
237 Run in debug mode with full diagnostic logs. Debug output lines are
238 always prefixed by #.
239 If --debug-json is used, additional LUKS2 JSON data structures are
241 printed.
242 --version, -V
244 Show the program version.
245 --usage
247 Show short option help.
248 --help, -?
250 Show help text and default parameters.
251
253 Report bugs at cryptsetup mailing list <cryptsetup@lists.linux.dev> or
254 in Issues project section
255 <https://gitlab.com/cryptsetup/cryptsetup/-/issues/new>.
256 Please attach output of the failed command with --debug option added.
258
260 Cryptsetup FAQ
261 <https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions>
262 cryptsetup(8), integritysetup(8) and veritysetup(8)
264
266 Part of cryptsetup project <https://gitlab.com/cryptsetup/cryptsetup/>.
267cryptsetup 2.5.0 2022-07-28 CRYPTSETUP-LUKSADDKEY(8)