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1 | SSH-KEYGEN(1) General Commands Manual SSH-KEYGEN(1) | ||
2 | |||
3 | NAME | ||
4 | ssh-keygen M-bM-^@M-^S authentication key generation, management and conversion | ||
5 | |||
6 | SYNOPSIS | ||
7 | ssh-keygen [-q] [-b bits] [-t dsa | ecdsa | ed25519 | rsa | rsa1] | ||
8 | [-N new_passphrase] [-C comment] [-f output_keyfile] | ||
9 | ssh-keygen -p [-P old_passphrase] [-N new_passphrase] [-f keyfile] | ||
10 | ssh-keygen -i [-m key_format] [-f input_keyfile] | ||
11 | ssh-keygen -e [-m key_format] [-f input_keyfile] | ||
12 | ssh-keygen -y [-f input_keyfile] | ||
13 | ssh-keygen -c [-P passphrase] [-C comment] [-f keyfile] | ||
14 | ssh-keygen -l [-v] [-E fingerprint_hash] [-f input_keyfile] | ||
15 | ssh-keygen -B [-f input_keyfile] | ||
16 | ssh-keygen -D pkcs11 | ||
17 | ssh-keygen -F hostname [-f known_hosts_file] [-l] | ||
18 | ssh-keygen -H [-f known_hosts_file] | ||
19 | ssh-keygen -R hostname [-f known_hosts_file] | ||
20 | ssh-keygen -r hostname [-f input_keyfile] [-g] | ||
21 | ssh-keygen -G output_file [-v] [-b bits] [-M memory] [-S start_point] | ||
22 | ssh-keygen -T output_file -f input_file [-v] [-a rounds] [-J num_lines] | ||
23 | [-j start_line] [-K checkpt] [-W generator] | ||
24 | ssh-keygen -s ca_key -I certificate_identity [-h] [-n principals] | ||
25 | [-O option] [-V validity_interval] [-z serial_number] file ... | ||
26 | ssh-keygen -L [-f input_keyfile] | ||
27 | ssh-keygen -A | ||
28 | ssh-keygen -k -f krl_file [-u] [-s ca_public] [-z version_number] | ||
29 | file ... | ||
30 | ssh-keygen -Q -f krl_file file ... | ||
31 | |||
32 | DESCRIPTION | ||
33 | ssh-keygen generates, manages and converts authentication keys for | ||
34 | ssh(1). ssh-keygen can create keys for use by SSH protocol versions 1 | ||
35 | and 2. Protocol 1 should not be used and is only offered to support | ||
36 | legacy devices. It suffers from a number of cryptographic weaknesses and | ||
37 | doesn't support many of the advanced features available for protocol 2. | ||
38 | |||
39 | The type of key to be generated is specified with the -t option. If | ||
40 | invoked without any arguments, ssh-keygen will generate an RSA key for | ||
41 | use in SSH protocol 2 connections. | ||
42 | |||
43 | ssh-keygen is also used to generate groups for use in Diffie-Hellman | ||
44 | group exchange (DH-GEX). See the MODULI GENERATION section for details. | ||
45 | |||
46 | Finally, ssh-keygen can be used to generate and update Key Revocation | ||
47 | Lists, and to test whether given keys have been revoked by one. See the | ||
48 | KEY REVOCATION LISTS section for details. | ||
49 | |||
50 | Normally each user wishing to use SSH with public key authentication runs | ||
51 | this once to create the authentication key in ~/.ssh/identity, | ||
52 | ~/.ssh/id_dsa, ~/.ssh/id_ecdsa, ~/.ssh/id_ed25519 or ~/.ssh/id_rsa. | ||
53 | Additionally, the system administrator may use this to generate host | ||
54 | keys, as seen in /etc/rc. | ||
55 | |||
56 | Normally this program generates the key and asks for a file in which to | ||
57 | store the private key. The public key is stored in a file with the same | ||
58 | name but M-bM-^@M-^\.pubM-bM-^@M-^] appended. The program also asks for a passphrase. The | ||
59 | passphrase may be empty to indicate no passphrase (host keys must have an | ||
60 | empty passphrase), or it may be a string of arbitrary length. A | ||
61 | passphrase is similar to a password, except it can be a phrase with a | ||
62 | series of words, punctuation, numbers, whitespace, or any string of | ||
63 | characters you want. Good passphrases are 10-30 characters long, are not | ||
64 | simple sentences or otherwise easily guessable (English prose has only | ||
65 | 1-2 bits of entropy per character, and provides very bad passphrases), | ||
66 | and contain a mix of upper and lowercase letters, numbers, and non- | ||
67 | alphanumeric characters. The passphrase can be changed later by using | ||
68 | the -p option. | ||
69 | |||
70 | There is no way to recover a lost passphrase. If the passphrase is lost | ||
71 | or forgotten, a new key must be generated and the corresponding public | ||
72 | key copied to other machines. | ||
73 | |||
74 | For RSA1 keys and keys stored in the newer OpenSSH format, there is also | ||
75 | a comment field in the key file that is only for convenience to the user | ||
76 | to help identify the key. The comment can tell what the key is for, or | ||
77 | whatever is useful. The comment is initialized to M-bM-^@M-^\user@hostM-bM-^@M-^] when the | ||
78 | key is created, but can be changed using the -c option. | ||
79 | |||
80 | After a key is generated, instructions below detail where the keys should | ||
81 | be placed to be activated. | ||
82 | |||
83 | The options are as follows: | ||
84 | |||
85 | -A For each of the key types (rsa1, rsa, dsa, ecdsa and ed25519) for | ||
86 | which host keys do not exist, generate the host keys with the | ||
87 | default key file path, an empty passphrase, default bits for the | ||
88 | key type, and default comment. This is used by /etc/rc to | ||
89 | generate new host keys. | ||
90 | |||
91 | -a rounds | ||
92 | When saving a new-format private key (i.e. an ed25519 key or any | ||
93 | SSH protocol 2 key when the -o flag is set), this option | ||
94 | specifies the number of KDF (key derivation function) rounds | ||
95 | used. Higher numbers result in slower passphrase verification | ||
96 | and increased resistance to brute-force password cracking (should | ||
97 | the keys be stolen). | ||
98 | |||
99 | When screening DH-GEX candidates ( using the -T command). This | ||
100 | option specifies the number of primality tests to perform. | ||
101 | |||
102 | -B Show the bubblebabble digest of specified private or public key | ||
103 | file. | ||
104 | |||
105 | -b bits | ||
106 | Specifies the number of bits in the key to create. For RSA keys, | ||
107 | the minimum size is 1024 bits and the default is 2048 bits. | ||
108 | Generally, 2048 bits is considered sufficient. DSA keys must be | ||
109 | exactly 1024 bits as specified by FIPS 186-2. For ECDSA keys, | ||
110 | the -b flag determines the key length by selecting from one of | ||
111 | three elliptic curve sizes: 256, 384 or 521 bits. Attempting to | ||
112 | use bit lengths other than these three values for ECDSA keys will | ||
113 | fail. Ed25519 keys have a fixed length and the -b flag will be | ||
114 | ignored. | ||
115 | |||
116 | -C comment | ||
117 | Provides a new comment. | ||
118 | |||
119 | -c Requests changing the comment in the private and public key | ||
120 | files. This operation is only supported for RSA1 keys and keys | ||
121 | stored in the newer OpenSSH format. The program will prompt for | ||
122 | the file containing the private keys, for the passphrase if the | ||
123 | key has one, and for the new comment. | ||
124 | |||
125 | -D pkcs11 | ||
126 | Download the RSA public keys provided by the PKCS#11 shared | ||
127 | library pkcs11. When used in combination with -s, this option | ||
128 | indicates that a CA key resides in a PKCS#11 token (see the | ||
129 | CERTIFICATES section for details). | ||
130 | |||
131 | -E fingerprint_hash | ||
132 | Specifies the hash algorithm used when displaying key | ||
133 | fingerprints. Valid options are: M-bM-^@M-^\md5M-bM-^@M-^] and M-bM-^@M-^\sha256M-bM-^@M-^]. The | ||
134 | default is M-bM-^@M-^\sha256M-bM-^@M-^]. | ||
135 | |||
136 | -e This option will read a private or public OpenSSH key file and | ||
137 | print to stdout the key in one of the formats specified by the -m | ||
138 | option. The default export format is M-bM-^@M-^\RFC4716M-bM-^@M-^]. This option | ||
139 | allows exporting OpenSSH keys for use by other programs, | ||
140 | including several commercial SSH implementations. | ||
141 | |||
142 | -F hostname | ||
143 | Search for the specified hostname in a known_hosts file, listing | ||
144 | any occurrences found. This option is useful to find hashed host | ||
145 | names or addresses and may also be used in conjunction with the | ||
146 | -H option to print found keys in a hashed format. | ||
147 | |||
148 | -f filename | ||
149 | Specifies the filename of the key file. | ||
150 | |||
151 | -G output_file | ||
152 | Generate candidate primes for DH-GEX. These primes must be | ||
153 | screened for safety (using the -T option) before use. | ||
154 | |||
155 | -g Use generic DNS format when printing fingerprint resource records | ||
156 | using the -r command. | ||
157 | |||
158 | -H Hash a known_hosts file. This replaces all hostnames and | ||
159 | addresses with hashed representations within the specified file; | ||
160 | the original content is moved to a file with a .old suffix. | ||
161 | These hashes may be used normally by ssh and sshd, but they do | ||
162 | not reveal identifying information should the file's contents be | ||
163 | disclosed. This option will not modify existing hashed hostnames | ||
164 | and is therefore safe to use on files that mix hashed and non- | ||
165 | hashed names. | ||
166 | |||
167 | -h When signing a key, create a host certificate instead of a user | ||
168 | certificate. Please see the CERTIFICATES section for details. | ||
169 | |||
170 | -I certificate_identity | ||
171 | Specify the key identity when signing a public key. Please see | ||
172 | the CERTIFICATES section for details. | ||
173 | |||
174 | -i This option will read an unencrypted private (or public) key file | ||
175 | in the format specified by the -m option and print an OpenSSH | ||
176 | compatible private (or public) key to stdout. This option allows | ||
177 | importing keys from other software, including several commercial | ||
178 | SSH implementations. The default import format is M-bM-^@M-^\RFC4716M-bM-^@M-^]. | ||
179 | |||
180 | -J num_lines | ||
181 | Exit after screening the specified number of lines while | ||
182 | performing DH candidate screening using the -T option. | ||
183 | |||
184 | -j start_line | ||
185 | Start screening at the specified line number while performing DH | ||
186 | candidate screening using the -T option. | ||
187 | |||
188 | -K checkpt | ||
189 | Write the last line processed to the file checkpt while | ||
190 | performing DH candidate screening using the -T option. This will | ||
191 | be used to skip lines in the input file that have already been | ||
192 | processed if the job is restarted. | ||
193 | |||
194 | -k Generate a KRL file. In this mode, ssh-keygen will generate a | ||
195 | KRL file at the location specified via the -f flag that revokes | ||
196 | every key or certificate presented on the command line. | ||
197 | Keys/certificates to be revoked may be specified by public key | ||
198 | file or using the format described in the KEY REVOCATION LISTS | ||
199 | section. | ||
200 | |||
201 | -L Prints the contents of one or more certificates. | ||
202 | |||
203 | -l Show fingerprint of specified public key file. Private RSA1 keys | ||
204 | are also supported. For RSA and DSA keys ssh-keygen tries to | ||
205 | find the matching public key file and prints its fingerprint. If | ||
206 | combined with -v, a visual ASCII art representation of the key is | ||
207 | supplied with the fingerprint. | ||
208 | |||
209 | -M memory | ||
210 | Specify the amount of memory to use (in megabytes) when | ||
211 | generating candidate moduli for DH-GEX. | ||
212 | |||
213 | -m key_format | ||
214 | Specify a key format for the -i (import) or -e (export) | ||
215 | conversion options. The supported key formats are: M-bM-^@M-^\RFC4716M-bM-^@M-^] | ||
216 | (RFC 4716/SSH2 public or private key), M-bM-^@M-^\PKCS8M-bM-^@M-^] (PEM PKCS8 public | ||
217 | key) or M-bM-^@M-^\PEMM-bM-^@M-^] (PEM public key). The default conversion format is | ||
218 | M-bM-^@M-^\RFC4716M-bM-^@M-^]. | ||
219 | |||
220 | -N new_passphrase | ||
221 | Provides the new passphrase. | ||
222 | |||
223 | -n principals | ||
224 | Specify one or more principals (user or host names) to be | ||
225 | included in a certificate when signing a key. Multiple | ||
226 | principals may be specified, separated by commas. Please see the | ||
227 | CERTIFICATES section for details. | ||
228 | |||
229 | -O option | ||
230 | Specify a certificate option when signing a key. This option may | ||
231 | be specified multiple times. Please see the CERTIFICATES section | ||
232 | for details. The options that are valid for user certificates | ||
233 | are: | ||
234 | |||
235 | clear Clear all enabled permissions. This is useful for | ||
236 | clearing the default set of permissions so permissions | ||
237 | may be added individually. | ||
238 | |||
239 | force-command=command | ||
240 | Forces the execution of command instead of any shell or | ||
241 | command specified by the user when the certificate is | ||
242 | used for authentication. | ||
243 | |||
244 | no-agent-forwarding | ||
245 | Disable ssh-agent(1) forwarding (permitted by default). | ||
246 | |||
247 | no-port-forwarding | ||
248 | Disable port forwarding (permitted by default). | ||
249 | |||
250 | no-pty Disable PTY allocation (permitted by default). | ||
251 | |||
252 | no-user-rc | ||
253 | Disable execution of ~/.ssh/rc by sshd(8) (permitted by | ||
254 | default). | ||
255 | |||
256 | no-x11-forwarding | ||
257 | Disable X11 forwarding (permitted by default). | ||
258 | |||
259 | permit-agent-forwarding | ||
260 | Allows ssh-agent(1) forwarding. | ||
261 | |||
262 | permit-port-forwarding | ||
263 | Allows port forwarding. | ||
264 | |||
265 | permit-pty | ||
266 | Allows PTY allocation. | ||
267 | |||
268 | permit-user-rc | ||
269 | Allows execution of ~/.ssh/rc by sshd(8). | ||
270 | |||
271 | permit-x11-forwarding | ||
272 | Allows X11 forwarding. | ||
273 | |||
274 | source-address=address_list | ||
275 | Restrict the source addresses from which the certificate | ||
276 | is considered valid. The address_list is a comma- | ||
277 | separated list of one or more address/netmask pairs in | ||
278 | CIDR format. | ||
279 | |||
280 | At present, no options are valid for host keys. | ||
281 | |||
282 | -o Causes ssh-keygen to save private keys using the new OpenSSH | ||
283 | format rather than the more compatible PEM format. The new | ||
284 | format has increased resistance to brute-force password cracking | ||
285 | but is not supported by versions of OpenSSH prior to 6.5. | ||
286 | Ed25519 keys always use the new private key format. | ||
287 | |||
288 | -P passphrase | ||
289 | Provides the (old) passphrase. | ||
290 | |||
291 | -p Requests changing the passphrase of a private key file instead of | ||
292 | creating a new private key. The program will prompt for the file | ||
293 | containing the private key, for the old passphrase, and twice for | ||
294 | the new passphrase. | ||
295 | |||
296 | -Q Test whether keys have been revoked in a KRL. | ||
297 | |||
298 | -q Silence ssh-keygen. | ||
299 | |||
300 | -R hostname | ||
301 | Removes all keys belonging to hostname from a known_hosts file. | ||
302 | This option is useful to delete hashed hosts (see the -H option | ||
303 | above). | ||
304 | |||
305 | -r hostname | ||
306 | Print the SSHFP fingerprint resource record named hostname for | ||
307 | the specified public key file. | ||
308 | |||
309 | -S start | ||
310 | Specify start point (in hex) when generating candidate moduli for | ||
311 | DH-GEX. | ||
312 | |||
313 | -s ca_key | ||
314 | Certify (sign) a public key using the specified CA key. Please | ||
315 | see the CERTIFICATES section for details. | ||
316 | |||
317 | When generating a KRL, -s specifies a path to a CA public key | ||
318 | file used to revoke certificates directly by key ID or serial | ||
319 | number. See the KEY REVOCATION LISTS section for details. | ||
320 | |||
321 | -T output_file | ||
322 | Test DH group exchange candidate primes (generated using the -G | ||
323 | option) for safety. | ||
324 | |||
325 | -t dsa | ecdsa | ed25519 | rsa | rsa1 | ||
326 | Specifies the type of key to create. The possible values are | ||
327 | M-bM-^@M-^\rsa1M-bM-^@M-^] for protocol version 1 and M-bM-^@M-^\dsaM-bM-^@M-^], M-bM-^@M-^\ecdsaM-bM-^@M-^], M-bM-^@M-^\ed25519M-bM-^@M-^], or | ||
328 | M-bM-^@M-^\rsaM-bM-^@M-^] for protocol version 2. | ||
329 | |||
330 | -u Update a KRL. When specified with -k, keys listed via the | ||
331 | command line are added to the existing KRL rather than a new KRL | ||
332 | being created. | ||
333 | |||
334 | -V validity_interval | ||
335 | Specify a validity interval when signing a certificate. A | ||
336 | validity interval may consist of a single time, indicating that | ||
337 | the certificate is valid beginning now and expiring at that time, | ||
338 | or may consist of two times separated by a colon to indicate an | ||
339 | explicit time interval. The start time may be specified as a | ||
340 | date in YYYYMMDD format, a time in YYYYMMDDHHMMSS format or a | ||
341 | relative time (to the current time) consisting of a minus sign | ||
342 | followed by a relative time in the format described in the TIME | ||
343 | FORMATS section of sshd_config(5). The end time may be specified | ||
344 | as a YYYYMMDD date, a YYYYMMDDHHMMSS time or a relative time | ||
345 | starting with a plus character. | ||
346 | |||
347 | For example: M-bM-^@M-^\+52w1dM-bM-^@M-^] (valid from now to 52 weeks and one day | ||
348 | from now), M-bM-^@M-^\-4w:+4wM-bM-^@M-^] (valid from four weeks ago to four weeks | ||
349 | from now), M-bM-^@M-^\20100101123000:20110101123000M-bM-^@M-^] (valid from 12:30 PM, | ||
350 | January 1st, 2010 to 12:30 PM, January 1st, 2011), M-bM-^@M-^\-1d:20110101M-bM-^@M-^] | ||
351 | (valid from yesterday to midnight, January 1st, 2011). | ||
352 | |||
353 | -v Verbose mode. Causes ssh-keygen to print debugging messages | ||
354 | about its progress. This is helpful for debugging moduli | ||
355 | generation. Multiple -v options increase the verbosity. The | ||
356 | maximum is 3. | ||
357 | |||
358 | -W generator | ||
359 | Specify desired generator when testing candidate moduli for DH- | ||
360 | GEX. | ||
361 | |||
362 | -y This option will read a private OpenSSH format file and print an | ||
363 | OpenSSH public key to stdout. | ||
364 | |||
365 | -z serial_number | ||
366 | Specifies a serial number to be embedded in the certificate to | ||
367 | distinguish this certificate from others from the same CA. The | ||
368 | default serial number is zero. | ||
369 | |||
370 | When generating a KRL, the -z flag is used to specify a KRL | ||
371 | version number. | ||
372 | |||
373 | MODULI GENERATION | ||
374 | ssh-keygen may be used to generate groups for the Diffie-Hellman Group | ||
375 | Exchange (DH-GEX) protocol. Generating these groups is a two-step | ||
376 | process: first, candidate primes are generated using a fast, but memory | ||
377 | intensive process. These candidate primes are then tested for | ||
378 | suitability (a CPU-intensive process). | ||
379 | |||
380 | Generation of primes is performed using the -G option. The desired | ||
381 | length of the primes may be specified by the -b option. For example: | ||
382 | |||
383 | # ssh-keygen -G moduli-2048.candidates -b 2048 | ||
384 | |||
385 | By default, the search for primes begins at a random point in the desired | ||
386 | length range. This may be overridden using the -S option, which | ||
387 | specifies a different start point (in hex). | ||
388 | |||
389 | Once a set of candidates have been generated, they must be screened for | ||
390 | suitability. This may be performed using the -T option. In this mode | ||
391 | ssh-keygen will read candidates from standard input (or a file specified | ||
392 | using the -f option). For example: | ||
393 | |||
394 | # ssh-keygen -T moduli-2048 -f moduli-2048.candidates | ||
395 | |||
396 | By default, each candidate will be subjected to 100 primality tests. | ||
397 | This may be overridden using the -a option. The DH generator value will | ||
398 | be chosen automatically for the prime under consideration. If a specific | ||
399 | generator is desired, it may be requested using the -W option. Valid | ||
400 | generator values are 2, 3, and 5. | ||
401 | |||
402 | Screened DH groups may be installed in /etc/moduli. It is important that | ||
403 | this file contains moduli of a range of bit lengths and that both ends of | ||
404 | a connection share common moduli. | ||
405 | |||
406 | CERTIFICATES | ||
407 | ssh-keygen supports signing of keys to produce certificates that may be | ||
408 | used for user or host authentication. Certificates consist of a public | ||
409 | key, some identity information, zero or more principal (user or host) | ||
410 | names and a set of options that are signed by a Certification Authority | ||
411 | (CA) key. Clients or servers may then trust only the CA key and verify | ||
412 | its signature on a certificate rather than trusting many user/host keys. | ||
413 | Note that OpenSSH certificates are a different, and much simpler, format | ||
414 | to the X.509 certificates used in ssl(8). | ||
415 | |||
416 | ssh-keygen supports two types of certificates: user and host. User | ||
417 | certificates authenticate users to servers, whereas host certificates | ||
418 | authenticate server hosts to users. To generate a user certificate: | ||
419 | |||
420 | $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub | ||
421 | |||
422 | The resultant certificate will be placed in /path/to/user_key-cert.pub. | ||
423 | A host certificate requires the -h option: | ||
424 | |||
425 | $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub | ||
426 | |||
427 | The host certificate will be output to /path/to/host_key-cert.pub. | ||
428 | |||
429 | It is possible to sign using a CA key stored in a PKCS#11 token by | ||
430 | providing the token library using -D and identifying the CA key by | ||
431 | providing its public half as an argument to -s: | ||
432 | |||
433 | $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id user_key.pub | ||
434 | |||
435 | In all cases, key_id is a "key identifier" that is logged by the server | ||
436 | when the certificate is used for authentication. | ||
437 | |||
438 | Certificates may be limited to be valid for a set of principal | ||
439 | (user/host) names. By default, generated certificates are valid for all | ||
440 | users or hosts. To generate a certificate for a specified set of | ||
441 | principals: | ||
442 | |||
443 | $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub | ||
444 | $ ssh-keygen -s ca_key -I key_id -h -n host.domain host_key.pub | ||
445 | |||
446 | Additional limitations on the validity and use of user certificates may | ||
447 | be specified through certificate options. A certificate option may | ||
448 | disable features of the SSH session, may be valid only when presented | ||
449 | from particular source addresses or may force the use of a specific | ||
450 | command. For a list of valid certificate options, see the documentation | ||
451 | for the -O option above. | ||
452 | |||
453 | Finally, certificates may be defined with a validity lifetime. The -V | ||
454 | option allows specification of certificate start and end times. A | ||
455 | certificate that is presented at a time outside this range will not be | ||
456 | considered valid. By default, certificates are valid from UNIX Epoch to | ||
457 | the distant future. | ||
458 | |||
459 | For certificates to be used for user or host authentication, the CA | ||
460 | public key must be trusted by sshd(8) or ssh(1). Please refer to those | ||
461 | manual pages for details. | ||
462 | |||
463 | KEY REVOCATION LISTS | ||
464 | ssh-keygen is able to manage OpenSSH format Key Revocation Lists (KRLs). | ||
465 | These binary files specify keys or certificates to be revoked using a | ||
466 | compact format, taking as little as one bit per certificate if they are | ||
467 | being revoked by serial number. | ||
468 | |||
469 | KRLs may be generated using the -k flag. This option reads one or more | ||
470 | files from the command line and generates a new KRL. The files may | ||
471 | either contain a KRL specification (see below) or public keys, listed one | ||
472 | per line. Plain public keys are revoked by listing their hash or | ||
473 | contents in the KRL and certificates revoked by serial number or key ID | ||
474 | (if the serial is zero or not available). | ||
475 | |||
476 | Revoking keys using a KRL specification offers explicit control over the | ||
477 | types of record used to revoke keys and may be used to directly revoke | ||
478 | certificates by serial number or key ID without having the complete | ||
479 | original certificate on hand. A KRL specification consists of lines | ||
480 | containing one of the following directives followed by a colon and some | ||
481 | directive-specific information. | ||
482 | |||
483 | serial: serial_number[-serial_number] | ||
484 | Revokes a certificate with the specified serial number. Serial | ||
485 | numbers are 64-bit values, not including zero and may be | ||
486 | expressed in decimal, hex or octal. If two serial numbers are | ||
487 | specified separated by a hyphen, then the range of serial numbers | ||
488 | including and between each is revoked. The CA key must have been | ||
489 | specified on the ssh-keygen command line using the -s option. | ||
490 | |||
491 | id: key_id | ||
492 | Revokes a certificate with the specified key ID string. The CA | ||
493 | key must have been specified on the ssh-keygen command line using | ||
494 | the -s option. | ||
495 | |||
496 | key: public_key | ||
497 | Revokes the specified key. If a certificate is listed, then it | ||
498 | is revoked as a plain public key. | ||
499 | |||
500 | sha1: public_key | ||
501 | Revokes the specified key by its SHA1 hash. | ||
502 | |||
503 | KRLs may be updated using the -u flag in addition to -k. When this | ||
504 | option is specified, keys listed via the command line are merged into the | ||
505 | KRL, adding to those already there. | ||
506 | |||
507 | It is also possible, given a KRL, to test whether it revokes a particular | ||
508 | key (or keys). The -Q flag will query an existing KRL, testing each key | ||
509 | specified on the command line. If any key listed on the command line has | ||
510 | been revoked (or an error encountered) then ssh-keygen will exit with a | ||
511 | non-zero exit status. A zero exit status will only be returned if no key | ||
512 | was revoked. | ||
513 | |||
514 | FILES | ||
515 | ~/.ssh/identity | ||
516 | Contains the protocol version 1 RSA authentication identity of | ||
517 | the user. This file should not be readable by anyone but the | ||
518 | user. It is possible to specify a passphrase when generating the | ||
519 | key; that passphrase will be used to encrypt the private part of | ||
520 | this file using 3DES. This file is not automatically accessed by | ||
521 | ssh-keygen but it is offered as the default file for the private | ||
522 | key. ssh(1) will read this file when a login attempt is made. | ||
523 | |||
524 | ~/.ssh/identity.pub | ||
525 | Contains the protocol version 1 RSA public key for | ||
526 | authentication. The contents of this file should be added to | ||
527 | ~/.ssh/authorized_keys on all machines where the user wishes to | ||
528 | log in using RSA authentication. There is no need to keep the | ||
529 | contents of this file secret. | ||
530 | |||
531 | ~/.ssh/id_dsa | ||
532 | ~/.ssh/id_ecdsa | ||
533 | ~/.ssh/id_ed25519 | ||
534 | ~/.ssh/id_rsa | ||
535 | Contains the protocol version 2 DSA, ECDSA, Ed25519 or RSA | ||
536 | authentication identity of the user. This file should not be | ||
537 | readable by anyone but the user. It is possible to specify a | ||
538 | passphrase when generating the key; that passphrase will be used | ||
539 | to encrypt the private part of this file using 128-bit AES. This | ||
540 | file is not automatically accessed by ssh-keygen but it is | ||
541 | offered as the default file for the private key. ssh(1) will | ||
542 | read this file when a login attempt is made. | ||
543 | |||
544 | ~/.ssh/id_dsa.pub | ||
545 | ~/.ssh/id_ecdsa.pub | ||
546 | ~/.ssh/id_ed25519.pub | ||
547 | ~/.ssh/id_rsa.pub | ||
548 | Contains the protocol version 2 DSA, ECDSA, Ed25519 or RSA public | ||
549 | key for authentication. The contents of this file should be | ||
550 | added to ~/.ssh/authorized_keys on all machines where the user | ||
551 | wishes to log in using public key authentication. There is no | ||
552 | need to keep the contents of this file secret. | ||
553 | |||
554 | /etc/moduli | ||
555 | Contains Diffie-Hellman groups used for DH-GEX. The file format | ||
556 | is described in moduli(5). | ||
557 | |||
558 | SEE ALSO | ||
559 | ssh(1), ssh-add(1), ssh-agent(1), moduli(5), sshd(8) | ||
560 | |||
561 | The Secure Shell (SSH) Public Key File Format, RFC 4716, 2006. | ||
562 | |||
563 | AUTHORS | ||
564 | OpenSSH is a derivative of the original and free ssh 1.2.12 release by | ||
565 | Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo | ||
566 | de Raadt and Dug Song removed many bugs, re-added newer features and | ||
567 | created OpenSSH. Markus Friedl contributed the support for SSH protocol | ||
568 | versions 1.5 and 2.0. | ||
569 | |||
570 | OpenBSD 6.0 June 16, 2016 OpenBSD 6.0 | ||