naddy@openbsd.org | b715fdc | 2020-01-18 21:16:43 +0000 | [diff] [blame] | 1 | .\" $OpenBSD: ssh-keygen.1,v 1.193 2020/01/18 21:16:43 naddy Exp $ |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 2 | .\" |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 3 | .\" Author: Tatu Ylonen <ylo@cs.hut.fi> |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 4 | .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 5 | .\" All rights reserved |
| 6 | .\" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 7 | .\" As far as I am concerned, the code I have written for this software |
| 8 | .\" can be used freely for any purpose. Any derived versions of this |
| 9 | .\" software must be clearly marked as such, and if the derived work is |
| 10 | .\" incompatible with the protocol description in the RFC file, it must be |
| 11 | .\" called by a name other than "ssh" or "Secure Shell". |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 12 | .\" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 13 | .\" |
Ben Lindstrom | 92a2e38 | 2001-03-05 06:59:27 +0000 | [diff] [blame] | 14 | .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved. |
| 15 | .\" Copyright (c) 1999 Aaron Campbell. All rights reserved. |
| 16 | .\" Copyright (c) 1999 Theo de Raadt. All rights reserved. |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 17 | .\" |
| 18 | .\" Redistribution and use in source and binary forms, with or without |
| 19 | .\" modification, are permitted provided that the following conditions |
| 20 | .\" are met: |
| 21 | .\" 1. Redistributions of source code must retain the above copyright |
| 22 | .\" notice, this list of conditions and the following disclaimer. |
| 23 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| 24 | .\" notice, this list of conditions and the following disclaimer in the |
| 25 | .\" documentation and/or other materials provided with the distribution. |
| 26 | .\" |
| 27 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 28 | .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 29 | .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 30 | .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 31 | .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 32 | .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 33 | .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 34 | .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 35 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 36 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 37 | .\" |
naddy@openbsd.org | 84911da | 2020-01-18 15:45:41 +0000 | [diff] [blame] | 38 | .Dd $Mdocdate: January 18 2020 $ |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 39 | .Dt SSH-KEYGEN 1 |
| 40 | .Os |
| 41 | .Sh NAME |
| 42 | .Nm ssh-keygen |
jmc@openbsd.org | 483cc72 | 2019-11-30 07:07:59 +0000 | [diff] [blame] | 43 | .Nd OpenSSH authentication key utility |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 44 | .Sh SYNOPSIS |
Damien Miller | bad5e03 | 2010-07-16 13:59:59 +1000 | [diff] [blame] | 45 | .Nm ssh-keygen |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 46 | .Op Fl q |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 47 | .Op Fl b Ar bits |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 48 | .Op Fl C Ar comment |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 49 | .Op Fl f Ar output_keyfile |
djm@openbsd.org | ecd2f33 | 2019-01-22 11:40:42 +0000 | [diff] [blame] | 50 | .Op Fl m Ar format |
djm@openbsd.org | 97dc5d1 | 2019-11-18 04:50:45 +0000 | [diff] [blame] | 51 | .Op Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 52 | .Op Fl N Ar new_passphrase |
naddy@openbsd.org | 0d005d6 | 2020-01-14 15:07:30 +0000 | [diff] [blame] | 53 | .Op Fl O Ar option |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 54 | .Op Fl w Ar provider |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 55 | .Nm ssh-keygen |
| 56 | .Fl p |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 57 | .Op Fl f Ar keyfile |
djm@openbsd.org | ecd2f33 | 2019-01-22 11:40:42 +0000 | [diff] [blame] | 58 | .Op Fl m Ar format |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 59 | .Op Fl N Ar new_passphrase |
| 60 | .Op Fl P Ar old_passphrase |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 61 | .Nm ssh-keygen |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 62 | .Fl i |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 63 | .Op Fl f Ar input_keyfile |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 64 | .Op Fl m Ar key_format |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 65 | .Nm ssh-keygen |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 66 | .Fl e |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 67 | .Op Fl f Ar input_keyfile |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 68 | .Op Fl m Ar key_format |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 69 | .Nm ssh-keygen |
| 70 | .Fl y |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 71 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 72 | .Nm ssh-keygen |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 73 | .Fl c |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 74 | .Op Fl C Ar comment |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 75 | .Op Fl f Ar keyfile |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 76 | .Op Fl P Ar passphrase |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 77 | .Nm ssh-keygen |
| 78 | .Fl l |
naddy@openbsd.org | 6288e3a | 2015-02-24 15:24:05 +0000 | [diff] [blame] | 79 | .Op Fl v |
djm@openbsd.org | 56d1c83 | 2014-12-21 22:27:55 +0000 | [diff] [blame] | 80 | .Op Fl E Ar fingerprint_hash |
Ben Lindstrom | 8fd372b | 2001-03-12 03:02:17 +0000 | [diff] [blame] | 81 | .Op Fl f Ar input_keyfile |
| 82 | .Nm ssh-keygen |
| 83 | .Fl B |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 84 | .Op Fl f Ar input_keyfile |
Ben Lindstrom | a1ec4a9 | 2001-08-06 21:51:34 +0000 | [diff] [blame] | 85 | .Nm ssh-keygen |
Damien Miller | 048dc93 | 2010-02-12 09:22:04 +1100 | [diff] [blame] | 86 | .Fl D Ar pkcs11 |
Ben Lindstrom | a1ec4a9 | 2001-08-06 21:51:34 +0000 | [diff] [blame] | 87 | .Nm ssh-keygen |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 88 | .Fl F Ar hostname |
jmc@openbsd.org | 6c91d42 | 2019-09-29 16:31:57 +0000 | [diff] [blame] | 89 | .Op Fl lv |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 90 | .Op Fl f Ar known_hosts_file |
| 91 | .Nm ssh-keygen |
| 92 | .Fl H |
| 93 | .Op Fl f Ar known_hosts_file |
| 94 | .Nm ssh-keygen |
djm@openbsd.org | 9039971 | 2020-01-02 22:40:09 +0000 | [diff] [blame] | 95 | .Fl K |
| 96 | .Op Fl w Ar provider |
| 97 | .Nm ssh-keygen |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 98 | .Fl R Ar hostname |
| 99 | .Op Fl f Ar known_hosts_file |
| 100 | .Nm ssh-keygen |
Damien Miller | 37876e9 | 2003-05-15 10:19:46 +1000 | [diff] [blame] | 101 | .Fl r Ar hostname |
Damien Miller | 37876e9 | 2003-05-15 10:19:46 +1000 | [diff] [blame] | 102 | .Op Fl g |
jmc@openbsd.org | 6c91d42 | 2019-09-29 16:31:57 +0000 | [diff] [blame] | 103 | .Op Fl f Ar input_keyfile |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 104 | .Nm ssh-keygen |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 105 | .Fl M Cm generate |
| 106 | .Op Fl O Ar option |
naddy@openbsd.org | 0d005d6 | 2020-01-14 15:07:30 +0000 | [diff] [blame] | 107 | .Ar output_file |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 108 | .Nm ssh-keygen |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 109 | .Fl M Cm screen |
naddy@openbsd.org | 0d005d6 | 2020-01-14 15:07:30 +0000 | [diff] [blame] | 110 | .Op Fl f Ar input_file |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 111 | .Op Fl O Ar option |
naddy@openbsd.org | 0d005d6 | 2020-01-14 15:07:30 +0000 | [diff] [blame] | 112 | .Ar output_file |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 113 | .Nm ssh-keygen |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 114 | .Fl I Ar certificate_identity |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 115 | .Fl s Ar ca_key |
jmc@openbsd.org | 6c91d42 | 2019-09-29 16:31:57 +0000 | [diff] [blame] | 116 | .Op Fl hU |
djm@openbsd.org | a98339e | 2017-06-28 01:09:22 +0000 | [diff] [blame] | 117 | .Op Fl D Ar pkcs11_provider |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 118 | .Op Fl n Ar principals |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 119 | .Op Fl O Ar option |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 120 | .Op Fl V Ar validity_interval |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 121 | .Op Fl z Ar serial_number |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 122 | .Ar |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 123 | .Nm ssh-keygen |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 124 | .Fl L |
| 125 | .Op Fl f Ar input_keyfile |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 126 | .Nm ssh-keygen |
| 127 | .Fl A |
djm@openbsd.org | 853edbe | 2017-07-07 03:53:12 +0000 | [diff] [blame] | 128 | .Op Fl f Ar prefix_path |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 129 | .Nm ssh-keygen |
| 130 | .Fl k |
| 131 | .Fl f Ar krl_file |
| 132 | .Op Fl u |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 133 | .Op Fl s Ar ca_public |
| 134 | .Op Fl z Ar version_number |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 135 | .Ar |
| 136 | .Nm ssh-keygen |
| 137 | .Fl Q |
| 138 | .Fl f Ar krl_file |
| 139 | .Ar |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 140 | .Nm ssh-keygen |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 141 | .Fl Y Cm check-novalidate |
| 142 | .Fl n Ar namespace |
| 143 | .Fl s Ar signature_file |
| 144 | .Nm ssh-keygen |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 145 | .Fl Y Cm sign |
| 146 | .Fl f Ar key_file |
| 147 | .Fl n Ar namespace |
| 148 | .Ar |
| 149 | .Nm ssh-keygen |
| 150 | .Fl Y Cm verify |
djm@openbsd.org | 8aa2aa3 | 2019-09-16 03:23:02 +0000 | [diff] [blame] | 151 | .Fl f Ar allowed_signers_file |
jmc@openbsd.org | 6918974 | 2019-10-03 17:07:50 +0000 | [diff] [blame] | 152 | .Fl I Ar signer_identity |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 153 | .Fl n Ar namespace |
| 154 | .Fl s Ar signature_file |
| 155 | .Op Fl r Ar revocation_file |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 156 | .Sh DESCRIPTION |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 157 | .Nm |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 158 | generates, manages and converts authentication keys for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 159 | .Xr ssh 1 . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 160 | .Nm |
jmc@openbsd.org | 2b6f799 | 2017-05-03 06:32:02 +0000 | [diff] [blame] | 161 | can create keys for use by SSH protocol version 2. |
jmc@openbsd.org | a685ae8 | 2016-02-17 07:38:19 +0000 | [diff] [blame] | 162 | .Pp |
Damien Miller | fbf486b | 2003-05-23 18:44:23 +1000 | [diff] [blame] | 163 | The type of key to be generated is specified with the |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 164 | .Fl t |
Damien Miller | a41c8b1 | 2002-01-22 23:05:08 +1100 | [diff] [blame] | 165 | option. |
Damien Miller | f14be5c | 2005-11-05 15:15:49 +1100 | [diff] [blame] | 166 | If invoked without any arguments, |
| 167 | .Nm |
naddy@openbsd.org | 2e9c324 | 2017-05-05 10:41:58 +0000 | [diff] [blame] | 168 | will generate an RSA key. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 169 | .Pp |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 170 | .Nm |
| 171 | is also used to generate groups for use in Diffie-Hellman group |
| 172 | exchange (DH-GEX). |
| 173 | See the |
| 174 | .Sx MODULI GENERATION |
| 175 | section for details. |
| 176 | .Pp |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 177 | Finally, |
| 178 | .Nm |
| 179 | can be used to generate and update Key Revocation Lists, and to test whether |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 180 | given keys have been revoked by one. |
| 181 | See the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 182 | .Sx KEY REVOCATION LISTS |
| 183 | section for details. |
| 184 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 185 | Normally each user wishing to use SSH |
Damien Miller | eb8b60e | 2010-08-31 22:41:14 +1000 | [diff] [blame] | 186 | with public key authentication runs this once to create the authentication |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 187 | key in |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 188 | .Pa ~/.ssh/id_dsa , |
Damien Miller | eb8b60e | 2010-08-31 22:41:14 +1000 | [diff] [blame] | 189 | .Pa ~/.ssh/id_ecdsa , |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 190 | .Pa ~/.ssh/id_ecdsa_sk , |
naddy@openbsd.org | f0edda8 | 2019-11-18 23:16:49 +0000 | [diff] [blame] | 191 | .Pa ~/.ssh/id_ed25519 , |
| 192 | .Pa ~/.ssh/id_ed25519_sk |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 193 | or |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 194 | .Pa ~/.ssh/id_rsa . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 195 | Additionally, the system administrator may use this to generate host keys, |
| 196 | as seen in |
| 197 | .Pa /etc/rc . |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 198 | .Pp |
| 199 | Normally this program generates the key and asks for a file in which |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 200 | to store the private key. |
| 201 | The public key is stored in a file with the same name but |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 202 | .Dq .pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 203 | appended. |
| 204 | The program also asks for a passphrase. |
| 205 | The passphrase may be empty to indicate no passphrase |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 206 | (host keys must have an empty passphrase), or it may be a string of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 207 | arbitrary length. |
Ben Lindstrom | 4e366d5 | 2001-12-06 16:43:21 +0000 | [diff] [blame] | 208 | A passphrase is similar to a password, except it can be a phrase with a |
| 209 | series of words, punctuation, numbers, whitespace, or any string of |
| 210 | characters you want. |
| 211 | Good passphrases are 10-30 characters long, are |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 212 | not simple sentences or otherwise easily guessable (English |
Ben Lindstrom | 2a097a4 | 2001-06-09 01:13:40 +0000 | [diff] [blame] | 213 | prose has only 1-2 bits of entropy per character, and provides very bad |
Ben Lindstrom | 4e366d5 | 2001-12-06 16:43:21 +0000 | [diff] [blame] | 214 | passphrases), and contain a mix of upper and lowercase letters, |
| 215 | numbers, and non-alphanumeric characters. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 216 | The passphrase can be changed later by using the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 217 | .Fl p |
| 218 | option. |
| 219 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 220 | There is no way to recover a lost passphrase. |
Damien Miller | 085c90f | 2011-05-05 14:15:33 +1000 | [diff] [blame] | 221 | If the passphrase is lost or forgotten, a new key must be generated |
| 222 | and the corresponding public key copied to other machines. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 223 | .Pp |
djm@openbsd.org | c45616a | 2019-01-22 11:00:15 +0000 | [diff] [blame] | 224 | .Nm |
| 225 | will by default write keys in an OpenSSH-specific format. |
| 226 | This format is preferred as it offers better protection for |
| 227 | keys at rest as well as allowing storage of key comments within |
| 228 | the private key file itself. |
| 229 | The key comment may be useful to help identify the key. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 230 | The comment is initialized to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 231 | .Dq user@host |
| 232 | when the key is created, but can be changed using the |
| 233 | .Fl c |
| 234 | option. |
| 235 | .Pp |
djm@openbsd.org | c45616a | 2019-01-22 11:00:15 +0000 | [diff] [blame] | 236 | It is still possible for |
| 237 | .Nm |
| 238 | to write the previously-used PEM format private keys using the |
| 239 | .Fl m |
| 240 | flag. |
| 241 | This may be used when generating new keys, and existing new-format |
| 242 | keys may be converted using this option in conjunction with the |
| 243 | .Fl p |
| 244 | (change passphrase) flag. |
| 245 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 246 | After a key is generated, instructions below detail where the keys |
| 247 | should be placed to be activated. |
| 248 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 249 | The options are as follows: |
| 250 | .Bl -tag -width Ds |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 251 | .It Fl A |
djm@openbsd.org | 97dc5d1 | 2019-11-18 04:50:45 +0000 | [diff] [blame] | 252 | For each of the key types (rsa, dsa, ecdsa and ed25519) |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 253 | for which host keys |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 254 | do not exist, generate the host keys with the default key file path, |
| 255 | an empty passphrase, default bits for the key type, and default comment. |
jmc@openbsd.org | dc44dd3 | 2017-07-08 18:32:54 +0000 | [diff] [blame] | 256 | If |
djm@openbsd.org | 853edbe | 2017-07-07 03:53:12 +0000 | [diff] [blame] | 257 | .Fl f |
jmc@openbsd.org | dc44dd3 | 2017-07-08 18:32:54 +0000 | [diff] [blame] | 258 | has also been specified, its argument is used as a prefix to the |
djm@openbsd.org | 853edbe | 2017-07-07 03:53:12 +0000 | [diff] [blame] | 259 | default path for the resulting host key files. |
Damien Miller | 3ca1eb3 | 2011-05-05 14:13:50 +1000 | [diff] [blame] | 260 | This is used by |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 261 | .Pa /etc/rc |
| 262 | to generate new host keys. |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 263 | .It Fl a Ar rounds |
jmc@openbsd.org | 3b44bf3 | 2019-09-27 20:03:24 +0000 | [diff] [blame] | 264 | When saving a private key, this option specifies the number of KDF |
djm@openbsd.org | ed7bd5d | 2018-08-08 01:16:01 +0000 | [diff] [blame] | 265 | (key derivation function) rounds used. |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 266 | Higher numbers result in slower passphrase verification and increased |
| 267 | resistance to brute-force password cracking (should the keys be stolen). |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 268 | .It Fl B |
| 269 | Show the bubblebabble digest of specified private or public key file. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 270 | .It Fl b Ar bits |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 271 | Specifies the number of bits in the key to create. |
dtucker@openbsd.org | d7c6e38 | 2019-04-19 05:47:44 +0000 | [diff] [blame] | 272 | For RSA keys, the minimum size is 1024 bits and the default is 3072 bits. |
| 273 | Generally, 3072 bits is considered sufficient. |
Darren Tucker | 9f64733 | 2005-11-28 16:41:46 +1100 | [diff] [blame] | 274 | DSA keys must be exactly 1024 bits as specified by FIPS 186-2. |
Damien Miller | ad21032 | 2011-05-05 14:15:54 +1000 | [diff] [blame] | 275 | For ECDSA keys, the |
| 276 | .Fl b |
Damien Miller | 6232a16 | 2011-09-22 21:36:00 +1000 | [diff] [blame] | 277 | flag determines the key length by selecting from one of three elliptic |
Damien Miller | ad21032 | 2011-05-05 14:15:54 +1000 | [diff] [blame] | 278 | curve sizes: 256, 384 or 521 bits. |
| 279 | Attempting to use bit lengths other than these three values for ECDSA keys |
| 280 | will fail. |
naddy@openbsd.org | f0edda8 | 2019-11-18 23:16:49 +0000 | [diff] [blame] | 281 | ECDSA-SK, Ed25519 and Ed25519-SK keys have a fixed length and the |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 282 | .Fl b |
| 283 | flag will be ignored. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 284 | .It Fl C Ar comment |
| 285 | Provides a new comment. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 286 | .It Fl c |
| 287 | Requests changing the comment in the private and public key files. |
| 288 | The program will prompt for the file containing the private keys, for |
Ben Lindstrom | aafff9c | 2001-05-06 03:01:02 +0000 | [diff] [blame] | 289 | the passphrase if the key has one, and for the new comment. |
Damien Miller | 7ea845e | 2010-02-12 09:21:02 +1100 | [diff] [blame] | 290 | .It Fl D Ar pkcs11 |
naddy@openbsd.org | c13b745 | 2019-03-05 16:17:12 +0000 | [diff] [blame] | 291 | Download the public keys provided by the PKCS#11 shared library |
Damien Miller | a761844 | 2010-02-12 09:26:02 +1100 | [diff] [blame] | 292 | .Ar pkcs11 . |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 293 | When used in combination with |
| 294 | .Fl s , |
| 295 | this option indicates that a CA key resides in a PKCS#11 token (see the |
| 296 | .Sx CERTIFICATES |
| 297 | section for details). |
djm@openbsd.org | 56d1c83 | 2014-12-21 22:27:55 +0000 | [diff] [blame] | 298 | .It Fl E Ar fingerprint_hash |
| 299 | Specifies the hash algorithm used when displaying key fingerprints. |
| 300 | Valid options are: |
| 301 | .Dq md5 |
| 302 | and |
| 303 | .Dq sha256 . |
| 304 | The default is |
| 305 | .Dq sha256 . |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 306 | .It Fl e |
Ben Lindstrom | 46c264f | 2001-04-24 16:56:58 +0000 | [diff] [blame] | 307 | This option will read a private or public OpenSSH key file and |
djm@openbsd.org | 180b520 | 2019-01-22 11:19:42 +0000 | [diff] [blame] | 308 | print to stdout a public key in one of the formats specified by the |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 309 | .Fl m |
| 310 | option. |
| 311 | The default export format is |
| 312 | .Dq RFC4716 . |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 313 | This option allows exporting OpenSSH keys for use by other programs, including |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 314 | several commercial SSH implementations. |
djm@openbsd.org | 737e4ed | 2018-12-07 03:32:26 +0000 | [diff] [blame] | 315 | .It Fl F Ar hostname | [hostname]:port |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 316 | Search for the specified |
| 317 | .Ar hostname |
djm@openbsd.org | 737e4ed | 2018-12-07 03:32:26 +0000 | [diff] [blame] | 318 | (with optional port number) |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 319 | in a |
| 320 | .Pa known_hosts |
| 321 | file, listing any occurrences found. |
| 322 | This option is useful to find hashed host names or addresses and may also be |
| 323 | used in conjunction with the |
| 324 | .Fl H |
| 325 | option to print found keys in a hashed format. |
| 326 | .It Fl f Ar filename |
| 327 | Specifies the filename of the key file. |
Damien Miller | 37876e9 | 2003-05-15 10:19:46 +1000 | [diff] [blame] | 328 | .It Fl g |
Darren Tucker | 0b42e6d | 2004-08-13 21:22:40 +1000 | [diff] [blame] | 329 | Use generic DNS format when printing fingerprint resource records using the |
Darren Tucker | 6e37037 | 2004-08-13 21:23:25 +1000 | [diff] [blame] | 330 | .Fl r |
Darren Tucker | 0b42e6d | 2004-08-13 21:22:40 +1000 | [diff] [blame] | 331 | command. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 332 | .It Fl H |
| 333 | Hash a |
| 334 | .Pa known_hosts |
Darren Tucker | da1adbc | 2005-03-14 23:15:58 +1100 | [diff] [blame] | 335 | file. |
| 336 | This replaces all hostnames and addresses with hashed representations |
| 337 | within the specified file; the original content is moved to a file with |
| 338 | a .old suffix. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 339 | These hashes may be used normally by |
| 340 | .Nm ssh |
| 341 | and |
| 342 | .Nm sshd , |
| 343 | but they do not reveal identifying information should the file's contents |
| 344 | be disclosed. |
| 345 | This option will not modify existing hashed hostnames and is therefore safe |
| 346 | to use on files that mix hashed and non-hashed names. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 347 | .It Fl h |
| 348 | When signing a key, create a host certificate instead of a user |
| 349 | certificate. |
| 350 | Please see the |
| 351 | .Sx CERTIFICATES |
| 352 | section for details. |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 353 | .It Fl I Ar certificate_identity |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 354 | Specify the key identity when signing a public key. |
| 355 | Please see the |
| 356 | .Sx CERTIFICATES |
| 357 | section for details. |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 358 | .It Fl i |
| 359 | This option will read an unencrypted private (or public) key file |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 360 | in the format specified by the |
| 361 | .Fl m |
| 362 | option and print an OpenSSH compatible private |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 363 | (or public) key to stdout. |
Damien Miller | 43b156c | 2014-04-20 13:23:03 +1000 | [diff] [blame] | 364 | This option allows importing keys from other software, including several |
| 365 | commercial SSH implementations. |
| 366 | The default import format is |
| 367 | .Dq RFC4716 . |
jmc@openbsd.org | c593cc5 | 2020-01-03 07:33:33 +0000 | [diff] [blame] | 368 | .It Fl K |
djm@openbsd.org | 9039971 | 2020-01-02 22:40:09 +0000 | [diff] [blame] | 369 | Download resident keys from a FIDO authenticator. |
| 370 | Public and private key files will be written to the current directory for |
| 371 | each downloaded key. |
| 372 | .It Fl k |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 373 | Generate a KRL file. |
| 374 | In this mode, |
| 375 | .Nm |
| 376 | will generate a KRL file at the location specified via the |
| 377 | .Fl f |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 378 | flag that revokes every key or certificate presented on the command line. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 379 | Keys/certificates to be revoked may be specified by public key file or |
| 380 | using the format described in the |
| 381 | .Sx KEY REVOCATION LISTS |
| 382 | section. |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 383 | .It Fl L |
djm@openbsd.org | 94bc0b7 | 2015-11-13 04:34:15 +0000 | [diff] [blame] | 384 | Prints the contents of one or more certificates. |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 385 | .It Fl l |
Darren Tucker | 35c4553 | 2008-06-13 04:43:15 +1000 | [diff] [blame] | 386 | Show fingerprint of specified public key file. |
Damien Miller | eb5fec6 | 2001-11-12 10:52:44 +1100 | [diff] [blame] | 387 | For RSA and DSA keys |
| 388 | .Nm |
Darren Tucker | f09e825 | 2008-06-13 05:18:03 +1000 | [diff] [blame] | 389 | tries to find the matching public key file and prints its fingerprint. |
| 390 | If combined with |
| 391 | .Fl v , |
jmc@openbsd.org | 9283884 | 2016-05-03 18:38:12 +0000 | [diff] [blame] | 392 | a visual ASCII art representation of the key is supplied with the |
djm@openbsd.org | cdcd941 | 2016-05-03 14:54:08 +0000 | [diff] [blame] | 393 | fingerprint. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 394 | .It Fl M Cm generate |
| 395 | Generate candidate Diffie-Hellman Group Exchange (DH-GEX) parameters for |
| 396 | eventual use by the |
| 397 | .Sq diffie-hellman-group-exchange-* |
| 398 | key exchange methods. |
| 399 | The numbers generated by this operation must be further screened before |
| 400 | use. |
| 401 | See the |
| 402 | .Sx MODULI GENERATION |
| 403 | section for more information. |
| 404 | .It Fl M Cm screen |
| 405 | Screen candidate parameters for Diffie-Hellman Group Exchange. |
| 406 | This will accept a list of candidate numbers and test that they are |
| 407 | safe (Sophie Germain) primes with acceptable group generators. |
| 408 | The results of this operation may be added to the |
| 409 | .Pa /etc/moduli |
| 410 | file. |
| 411 | See the |
| 412 | .Sx MODULI GENERATION |
| 413 | section for more information. |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 414 | .It Fl m Ar key_format |
djm@openbsd.org | ecd2f33 | 2019-01-22 11:40:42 +0000 | [diff] [blame] | 415 | Specify a key format for key generation, the |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 416 | .Fl i |
djm@openbsd.org | ecd2f33 | 2019-01-22 11:40:42 +0000 | [diff] [blame] | 417 | (import), |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 418 | .Fl e |
djm@openbsd.org | ecd2f33 | 2019-01-22 11:40:42 +0000 | [diff] [blame] | 419 | (export) conversion options, and the |
| 420 | .Fl p |
| 421 | change passphrase operation. |
| 422 | The latter may be used to convert between OpenSSH private key and PEM |
| 423 | private key formats. |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 424 | The supported key formats are: |
| 425 | .Dq RFC4716 |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 426 | (RFC 4716/SSH2 public or private key), |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 427 | .Dq PKCS8 |
djm@openbsd.org | eb0d8e7 | 2019-07-15 13:16:29 +0000 | [diff] [blame] | 428 | (PKCS8 public or private key) |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 429 | or |
| 430 | .Dq PEM |
| 431 | (PEM public key). |
djm@openbsd.org | eb0d8e7 | 2019-07-15 13:16:29 +0000 | [diff] [blame] | 432 | By default OpenSSH will write newly-generated private keys in its own |
| 433 | format, but when converting public keys for export the default format is |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 434 | .Dq RFC4716 . |
djm@openbsd.org | ed7bd5d | 2018-08-08 01:16:01 +0000 | [diff] [blame] | 435 | Setting a format of |
| 436 | .Dq PEM |
| 437 | when generating or updating a supported private key type will cause the |
| 438 | key to be stored in the legacy PEM private key format. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 439 | .It Fl N Ar new_passphrase |
| 440 | Provides the new passphrase. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 441 | .It Fl n Ar principals |
| 442 | Specify one or more principals (user or host names) to be included in |
| 443 | a certificate when signing a key. |
| 444 | Multiple principals may be specified, separated by commas. |
| 445 | Please see the |
| 446 | .Sx CERTIFICATES |
| 447 | section for details. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 448 | .It Fl O Ar option |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 449 | Specify a key/value option. |
| 450 | These are specific to the operation that |
| 451 | .Nm |
| 452 | has been requested to perform. |
| 453 | .Pp |
| 454 | When signing certificates, one of the options listed in the |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 455 | .Sx CERTIFICATES |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 456 | section may be specified here. |
| 457 | .Pp |
| 458 | When performing moduli generation or screening, one of the options |
| 459 | listed in the |
| 460 | .Sx MODULI GENERATION |
| 461 | section may be specified. |
| 462 | .Pp |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 463 | When generating a key that will be hosted on a FIDO authenticator, |
| 464 | this flag may be used to specify key-specific options. |
| 465 | Those supported at present are: |
| 466 | .Bl -tag -width Ds |
| 467 | .It Cm application |
| 468 | Override the default FIDO application/origin string of |
djm@openbsd.org | c312ca0 | 2020-01-06 02:00:46 +0000 | [diff] [blame] | 469 | .Dq ssh: . |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 470 | This may be useful when generating host or domain-specific resident keys. |
| 471 | .It Cm device |
| 472 | Explicitly specify a |
djm@openbsd.org | c312ca0 | 2020-01-06 02:00:46 +0000 | [diff] [blame] | 473 | .Xr fido 4 |
| 474 | device to use, rather than letting the token middleware select one. |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 475 | .It Cm no-touch-required |
| 476 | Indicate that the generated private key should not require touch |
djm@openbsd.org | 3093d12 | 2019-12-30 09:49:52 +0000 | [diff] [blame] | 477 | events (user presence) when making signatures. |
| 478 | Note that |
| 479 | .Xr sshd 8 |
| 480 | will refuse such signatures by default, unless overridden via |
| 481 | an authorized_keys option. |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 482 | .It Cm resident |
| 483 | Indicate that the key should be stored on the FIDO authenticator itself. |
djm@openbsd.org | 3093d12 | 2019-12-30 09:49:52 +0000 | [diff] [blame] | 484 | Resident keys may be supported on FIDO2 tokens and typically require that |
| 485 | a PIN be set on the token prior to generation. |
| 486 | Resident keys may be loaded off the token using |
| 487 | .Xr ssh-add 1 . |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 488 | .It Cm user |
| 489 | A username to be associated with a resident key, |
djm@openbsd.org | c312ca0 | 2020-01-06 02:00:46 +0000 | [diff] [blame] | 490 | overriding the empty default username. |
| 491 | Specifying a username may be useful when generating multiple resident keys |
| 492 | for the same application name. |
jmc@openbsd.org | cd53476 | 2020-01-06 07:43:28 +0000 | [diff] [blame] | 493 | .El |
djm@openbsd.org | 3093d12 | 2019-12-30 09:49:52 +0000 | [diff] [blame] | 494 | .Pp |
| 495 | The |
| 496 | .Fl O |
| 497 | option may be specified multiple times. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 498 | .It Fl P Ar passphrase |
| 499 | Provides the (old) passphrase. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 500 | .It Fl p |
| 501 | Requests changing the passphrase of a private key file instead of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 502 | creating a new private key. |
| 503 | The program will prompt for the file |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 504 | containing the private key, for the old passphrase, and twice for the |
| 505 | new passphrase. |
Damien Miller | 072fdcd | 2013-01-20 22:34:04 +1100 | [diff] [blame] | 506 | .It Fl Q |
| 507 | Test whether keys have been revoked in a KRL. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 508 | .It Fl q |
| 509 | Silence |
| 510 | .Nm ssh-keygen . |
djm@openbsd.org | 63bba57 | 2018-12-07 03:33:18 +0000 | [diff] [blame] | 511 | .It Fl R Ar hostname | [hostname]:port |
djm@openbsd.org | 737e4ed | 2018-12-07 03:32:26 +0000 | [diff] [blame] | 512 | Removes all keys belonging to the specified |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 513 | .Ar hostname |
djm@openbsd.org | 737e4ed | 2018-12-07 03:32:26 +0000 | [diff] [blame] | 514 | (with optional port number) |
Damien Miller | 4c9c6fd | 2005-03-02 12:03:43 +1100 | [diff] [blame] | 515 | from a |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 516 | .Pa known_hosts |
| 517 | file. |
Damien Miller | 4c9c6fd | 2005-03-02 12:03:43 +1100 | [diff] [blame] | 518 | This option is useful to delete hashed hosts (see the |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 519 | .Fl H |
| 520 | option above). |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 521 | .It Fl r Ar hostname |
| 522 | Print the SSHFP fingerprint resource record named |
| 523 | .Ar hostname |
| 524 | for the specified public key file. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 525 | .It Fl s Ar ca_key |
| 526 | Certify (sign) a public key using the specified CA key. |
| 527 | Please see the |
| 528 | .Sx CERTIFICATES |
| 529 | section for details. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 530 | .Pp |
| 531 | When generating a KRL, |
| 532 | .Fl s |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 533 | specifies a path to a CA public key file used to revoke certificates directly |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 534 | by key ID or serial number. |
| 535 | See the |
| 536 | .Sx KEY REVOCATION LISTS |
| 537 | section for details. |
djm@openbsd.org | 97dc5d1 | 2019-11-18 04:50:45 +0000 | [diff] [blame] | 538 | .It Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 539 | Specifies the type of key to create. |
| 540 | The possible values are |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 541 | .Dq dsa , |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 542 | .Dq ecdsa , |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 543 | .Dq ecdsa-sk , |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 544 | .Dq ed25519 , |
djm@openbsd.org | 97dc5d1 | 2019-11-18 04:50:45 +0000 | [diff] [blame] | 545 | .Dq ed25519-sk , |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 546 | or |
jmc@openbsd.org | f10c0d3 | 2017-05-02 17:04:09 +0000 | [diff] [blame] | 547 | .Dq rsa . |
djm@openbsd.org | 476e355 | 2019-05-20 00:20:35 +0000 | [diff] [blame] | 548 | .Pp |
| 549 | This flag may also be used to specify the desired signature type when |
jmc@openbsd.org | 85ceb0e | 2019-05-20 06:01:59 +0000 | [diff] [blame] | 550 | signing certificates using an RSA CA key. |
djm@openbsd.org | 476e355 | 2019-05-20 00:20:35 +0000 | [diff] [blame] | 551 | The available RSA signature variants are |
| 552 | .Dq ssh-rsa |
| 553 | (SHA1 signatures, not recommended), |
jmc@openbsd.org | 85ceb0e | 2019-05-20 06:01:59 +0000 | [diff] [blame] | 554 | .Dq rsa-sha2-256 , |
| 555 | and |
djm@openbsd.org | 476e355 | 2019-05-20 00:20:35 +0000 | [diff] [blame] | 556 | .Dq rsa-sha2-512 |
| 557 | (the default). |
djm@openbsd.org | a98339e | 2017-06-28 01:09:22 +0000 | [diff] [blame] | 558 | .It Fl U |
| 559 | When used in combination with |
| 560 | .Fl s , |
| 561 | this option indicates that a CA key resides in a |
| 562 | .Xr ssh-agent 1 . |
| 563 | See the |
| 564 | .Sx CERTIFICATES |
| 565 | section for more information. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 566 | .It Fl u |
| 567 | Update a KRL. |
| 568 | When specified with |
| 569 | .Fl k , |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 570 | keys listed via the command line are added to the existing KRL rather than |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 571 | a new KRL being created. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 572 | .It Fl V Ar validity_interval |
| 573 | Specify a validity interval when signing a certificate. |
| 574 | A validity interval may consist of a single time, indicating that the |
| 575 | certificate is valid beginning now and expiring at that time, or may consist |
| 576 | of two times separated by a colon to indicate an explicit time interval. |
djm@openbsd.org@openbsd.org | d52131a | 2017-11-03 05:14:04 +0000 | [diff] [blame] | 577 | .Pp |
| 578 | The start time may be specified as the string |
| 579 | .Dq always |
| 580 | to indicate the certificate has no specified start time, |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 581 | a date in YYYYMMDD format, a time in YYYYMMDDHHMM[SS] format, |
djm@openbsd.org@openbsd.org | d52131a | 2017-11-03 05:14:04 +0000 | [diff] [blame] | 582 | a relative time (to the current time) consisting of a minus sign followed by |
| 583 | an interval in the format described in the |
Damien Miller | fecfd11 | 2013-07-18 16:11:50 +1000 | [diff] [blame] | 584 | TIME FORMATS section of |
Damien Miller | 77497e1 | 2010-03-22 05:50:51 +1100 | [diff] [blame] | 585 | .Xr sshd_config 5 . |
djm@openbsd.org@openbsd.org | d52131a | 2017-11-03 05:14:04 +0000 | [diff] [blame] | 586 | .Pp |
djm@openbsd.org | bf0fbf2 | 2018-03-12 00:52:01 +0000 | [diff] [blame] | 587 | The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMM[SS] time, |
djm@openbsd.org@openbsd.org | d52131a | 2017-11-03 05:14:04 +0000 | [diff] [blame] | 588 | a relative time starting with a plus character or the string |
| 589 | .Dq forever |
| 590 | to indicate that the certificate has no expirty date. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 591 | .Pp |
| 592 | For example: |
| 593 | .Dq +52w1d |
| 594 | (valid from now to 52 weeks and one day from now), |
| 595 | .Dq -4w:+4w |
| 596 | (valid from four weeks ago to four weeks from now), |
| 597 | .Dq 20100101123000:20110101123000 |
| 598 | (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011), |
| 599 | .Dq -1d:20110101 |
| 600 | (valid from yesterday to midnight, January 1st, 2011). |
djm@openbsd.org@openbsd.org | d52131a | 2017-11-03 05:14:04 +0000 | [diff] [blame] | 601 | .Dq -1m:forever |
| 602 | (valid from one minute ago and never expiring). |
Darren Tucker | 06930c7 | 2003-12-31 11:34:51 +1100 | [diff] [blame] | 603 | .It Fl v |
| 604 | Verbose mode. |
| 605 | Causes |
| 606 | .Nm |
| 607 | to print debugging messages about its progress. |
| 608 | This is helpful for debugging moduli generation. |
| 609 | Multiple |
| 610 | .Fl v |
| 611 | options increase the verbosity. |
| 612 | The maximum is 3. |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 613 | .It Fl w Ar provider |
naddy@openbsd.org | 141df48 | 2019-12-21 20:22:34 +0000 | [diff] [blame] | 614 | Specifies a path to a library that will be used when creating |
| 615 | FIDO authenticator-hosted keys, overriding the default of using |
| 616 | the internal USB HID support. |
jmc@openbsd.org | 20ccd85 | 2019-12-27 08:28:44 +0000 | [diff] [blame] | 617 | .It Fl Y Cm check-novalidate |
| 618 | Checks that a signature generated using |
| 619 | .Nm |
| 620 | .Fl Y Cm sign |
| 621 | has a valid structure. |
| 622 | This does not validate if a signature comes from an authorized signer. |
| 623 | When testing a signature, |
| 624 | .Nm |
| 625 | accepts a message on standard input and a signature namespace using |
| 626 | .Fl n . |
| 627 | A file containing the corresponding signature must also be supplied using the |
| 628 | .Fl s |
| 629 | flag. |
| 630 | Successful testing of the signature is signalled by |
| 631 | .Nm |
| 632 | returning a zero exit status. |
jmc@openbsd.org | f23d91f | 2019-09-05 05:47:23 +0000 | [diff] [blame] | 633 | .It Fl Y Cm sign |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 634 | Cryptographically sign a file or some data using a SSH key. |
| 635 | When signing, |
| 636 | .Nm |
| 637 | accepts zero or more files to sign on the command-line - if no files |
| 638 | are specified then |
| 639 | .Nm |
| 640 | will sign data presented on standard input. |
| 641 | Signatures are written to the path of the input file with |
| 642 | .Dq .sig |
| 643 | appended, or to standard output if the message to be signed was read from |
| 644 | standard input. |
| 645 | .Pp |
| 646 | The key used for signing is specified using the |
| 647 | .Fl f |
| 648 | option and may refer to either a private key, or a public key with the private |
| 649 | half available via |
| 650 | .Xr ssh-agent 1 . |
| 651 | An additional signature namespace, used to prevent signature confusion across |
| 652 | different domains of use (e.g. file signing vs email signing) must be provided |
| 653 | via the |
| 654 | .Fl n |
| 655 | flag. |
| 656 | Namespaces are arbitrary strings, and may include: |
| 657 | .Dq file |
| 658 | for file signing, |
| 659 | .Dq email |
| 660 | for email signing. |
| 661 | For custom uses, it is recommended to use names following a |
| 662 | NAMESPACE@YOUR.DOMAIN pattern to generate unambiguous namespaces. |
jmc@openbsd.org | f23d91f | 2019-09-05 05:47:23 +0000 | [diff] [blame] | 663 | .It Fl Y Cm verify |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 664 | Request to verify a signature generated using |
| 665 | .Nm |
jmc@openbsd.org | f23d91f | 2019-09-05 05:47:23 +0000 | [diff] [blame] | 666 | .Fl Y Cm sign |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 667 | as described above. |
| 668 | When verifying a signature, |
| 669 | .Nm |
| 670 | accepts a message on standard input and a signature namespace using |
| 671 | .Fl n . |
| 672 | A file containing the corresponding signature must also be supplied using the |
| 673 | .Fl s |
| 674 | flag, along with the identity of the signer using |
| 675 | .Fl I |
| 676 | and a list of allowed signers via the |
| 677 | .Fl f |
| 678 | flag. |
| 679 | The format of the allowed signers file is documented in the |
| 680 | .Sx ALLOWED SIGNERS |
| 681 | section below. |
| 682 | A file containing revoked keys can be passed using the |
| 683 | .Fl r |
jmc@openbsd.org | db1e6f6 | 2019-09-04 05:56:54 +0000 | [diff] [blame] | 684 | flag. |
| 685 | The revocation file may be a KRL or a one-per-line list of public keys. |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 686 | Successful verification by an authorized signer is signalled by |
| 687 | .Nm |
jmc@openbsd.org | 70fc9a6 | 2019-10-22 08:50:35 +0000 | [diff] [blame] | 688 | returning a zero exit status. |
jmc@openbsd.org | 5b6c954 | 2019-12-27 08:25:07 +0000 | [diff] [blame] | 689 | .It Fl y |
| 690 | This option will read a private |
| 691 | OpenSSH format file and print an OpenSSH public key to stdout. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 692 | .It Fl z Ar serial_number |
| 693 | Specifies a serial number to be embedded in the certificate to distinguish |
| 694 | this certificate from others from the same CA. |
djm@openbsd.org | be06394 | 2019-01-23 04:51:02 +0000 | [diff] [blame] | 695 | If the |
| 696 | .Ar serial_number |
| 697 | is prefixed with a |
| 698 | .Sq + |
| 699 | character, then the serial number will be incremented for each certificate |
| 700 | signed on a single command-line. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 701 | The default serial number is zero. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 702 | .Pp |
| 703 | When generating a KRL, the |
| 704 | .Fl z |
| 705 | flag is used to specify a KRL version number. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 706 | .El |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 707 | .Sh MODULI GENERATION |
| 708 | .Nm |
| 709 | may be used to generate groups for the Diffie-Hellman Group Exchange |
| 710 | (DH-GEX) protocol. |
| 711 | Generating these groups is a two-step process: first, candidate |
| 712 | primes are generated using a fast, but memory intensive process. |
| 713 | These candidate primes are then tested for suitability (a CPU-intensive |
| 714 | process). |
| 715 | .Pp |
| 716 | Generation of primes is performed using the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 717 | .Fl M Cm generate |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 718 | option. |
| 719 | The desired length of the primes may be specified by the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 720 | .Fl O Cm bits |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 721 | option. |
| 722 | For example: |
| 723 | .Pp |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 724 | .Dl # ssh-keygen -M generate -O bits=2048 moduli-2048.candidates |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 725 | .Pp |
| 726 | By default, the search for primes begins at a random point in the |
| 727 | desired length range. |
| 728 | This may be overridden using the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 729 | .Fl O Cm start |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 730 | option, which specifies a different start point (in hex). |
| 731 | .Pp |
Damien Miller | dfceafe | 2012-07-06 13:44:19 +1000 | [diff] [blame] | 732 | Once a set of candidates have been generated, they must be screened for |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 733 | suitability. |
| 734 | This may be performed using the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 735 | .Fl M Cm screen |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 736 | option. |
| 737 | In this mode |
| 738 | .Nm |
| 739 | will read candidates from standard input (or a file specified using the |
| 740 | .Fl f |
| 741 | option). |
| 742 | For example: |
| 743 | .Pp |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 744 | .Dl # ssh-keygen -M screen -f moduli-2048.candidates moduli-2048 |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 745 | .Pp |
| 746 | By default, each candidate will be subjected to 100 primality tests. |
| 747 | This may be overridden using the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 748 | .Fl O Cm prime-tests |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 749 | option. |
| 750 | The DH generator value will be chosen automatically for the |
| 751 | prime under consideration. |
| 752 | If a specific generator is desired, it may be requested using the |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 753 | .Fl O Cm generator |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 754 | option. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 755 | Valid generator values are 2, 3, and 5. |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 756 | .Pp |
| 757 | Screened DH groups may be installed in |
| 758 | .Pa /etc/moduli . |
| 759 | It is important that this file contains moduli of a range of bit lengths and |
| 760 | that both ends of a connection share common moduli. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 761 | .Pp |
| 762 | A number of options are available for moduli generation and screening via the |
| 763 | .Fl O |
| 764 | flag: |
jmc@openbsd.org | 3b1382f | 2019-12-30 16:10:00 +0000 | [diff] [blame] | 765 | .Bl -tag -width Ds |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 766 | .It Ic lines Ns = Ns Ar number |
| 767 | Exit after screening the specified number of lines while performing DH |
| 768 | candidate screening. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 769 | .It Ic start-line Ns = Ns Ar line-number |
| 770 | Start screening at the specified line number while performing DH candidate |
| 771 | screening. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 772 | .It Ic checkpoint Ns = Ns Ar filename |
| 773 | Write the last line processed to the specified file while performing DH |
| 774 | candidate screening. |
| 775 | This will be used to skip lines in the input file that have already been |
| 776 | processed if the job is restarted. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 777 | .It Ic memory Ns = Ns Ar mbytes |
| 778 | Specify the amount of memory to use (in megabytes) when generating |
| 779 | candidate moduli for DH-GEX. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 780 | .It Ic start Ns = Ns Ar hex-value |
| 781 | Specify start point (in hex) when generating candidate moduli for DH-GEX. |
djm@openbsd.org | 3e60d18 | 2019-12-30 03:30:09 +0000 | [diff] [blame] | 782 | .It Ic generator Ns = Ns Ar value |
| 783 | Specify desired generator (in decimal) when testing candidate moduli for DH-GEX. |
| 784 | .El |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 785 | .Sh CERTIFICATES |
| 786 | .Nm |
| 787 | supports signing of keys to produce certificates that may be used for |
| 788 | user or host authentication. |
| 789 | Certificates consist of a public key, some identity information, zero or |
Damien Miller | 1f18142 | 2010-04-18 08:08:03 +1000 | [diff] [blame] | 790 | more principal (user or host) names and a set of options that |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 791 | are signed by a Certification Authority (CA) key. |
| 792 | Clients or servers may then trust only the CA key and verify its signature |
| 793 | on a certificate rather than trusting many user/host keys. |
| 794 | Note that OpenSSH certificates are a different, and much simpler, format to |
| 795 | the X.509 certificates used in |
| 796 | .Xr ssl 8 . |
| 797 | .Pp |
| 798 | .Nm |
| 799 | supports two types of certificates: user and host. |
| 800 | User certificates authenticate users to servers, whereas host certificates |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 801 | authenticate server hosts to users. |
| 802 | To generate a user certificate: |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 803 | .Pp |
| 804 | .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub |
| 805 | .Pp |
| 806 | The resultant certificate will be placed in |
Damien Miller | 1b61a28 | 2010-03-22 05:55:06 +1100 | [diff] [blame] | 807 | .Pa /path/to/user_key-cert.pub . |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 808 | A host certificate requires the |
| 809 | .Fl h |
| 810 | option: |
| 811 | .Pp |
| 812 | .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub |
| 813 | .Pp |
| 814 | The host certificate will be output to |
Damien Miller | 1b61a28 | 2010-03-22 05:55:06 +1100 | [diff] [blame] | 815 | .Pa /path/to/host_key-cert.pub . |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 816 | .Pp |
| 817 | It is possible to sign using a CA key stored in a PKCS#11 token by |
| 818 | providing the token library using |
| 819 | .Fl D |
| 820 | and identifying the CA key by providing its public half as an argument |
| 821 | to |
| 822 | .Fl s : |
| 823 | .Pp |
naddy@openbsd.org | 05291e5 | 2015-08-20 19:20:06 +0000 | [diff] [blame] | 824 | .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id user_key.pub |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 825 | .Pp |
djm@openbsd.org | a98339e | 2017-06-28 01:09:22 +0000 | [diff] [blame] | 826 | Similarly, it is possible for the CA key to be hosted in a |
| 827 | .Xr ssh-agent 1 . |
| 828 | This is indicated by the |
| 829 | .Fl U |
| 830 | flag and, again, the CA key must be identified by its public half. |
| 831 | .Pp |
| 832 | .Dl $ ssh-keygen -Us ca_key.pub -I key_id user_key.pub |
| 833 | .Pp |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 834 | In all cases, |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 835 | .Ar key_id |
| 836 | is a "key identifier" that is logged by the server when the certificate |
| 837 | is used for authentication. |
| 838 | .Pp |
| 839 | Certificates may be limited to be valid for a set of principal (user/host) |
| 840 | names. |
| 841 | By default, generated certificates are valid for all users or hosts. |
| 842 | To generate a certificate for a specified set of principals: |
| 843 | .Pp |
| 844 | .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub |
naddy@openbsd.org | 05291e5 | 2015-08-20 19:20:06 +0000 | [diff] [blame] | 845 | .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain host_key.pub" |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 846 | .Pp |
| 847 | Additional limitations on the validity and use of user certificates may |
Damien Miller | 1f18142 | 2010-04-18 08:08:03 +1000 | [diff] [blame] | 848 | be specified through certificate options. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 849 | A certificate option may disable features of the SSH session, may be |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 850 | valid only when presented from particular source addresses or may |
| 851 | force the use of a specific command. |
djm@openbsd.org | 1e645fe | 2019-12-30 03:28:41 +0000 | [diff] [blame] | 852 | .Pp |
| 853 | The options that are valid for user certificates are: |
| 854 | .Pp |
| 855 | .Bl -tag -width Ds -compact |
| 856 | .It Ic clear |
| 857 | Clear all enabled permissions. |
| 858 | This is useful for clearing the default set of permissions so permissions may |
| 859 | be added individually. |
| 860 | .Pp |
| 861 | .It Ic critical : Ns Ar name Ns Op Ns = Ns Ar contents |
| 862 | .It Ic extension : Ns Ar name Ns Op Ns = Ns Ar contents |
| 863 | Includes an arbitrary certificate critical option or extension. |
| 864 | The specified |
| 865 | .Ar name |
| 866 | should include a domain suffix, e.g.\& |
| 867 | .Dq name@example.com . |
| 868 | If |
| 869 | .Ar contents |
| 870 | is specified then it is included as the contents of the extension/option |
| 871 | encoded as a string, otherwise the extension/option is created with no |
| 872 | contents (usually indicating a flag). |
| 873 | Extensions may be ignored by a client or server that does not recognise them, |
| 874 | whereas unknown critical options will cause the certificate to be refused. |
| 875 | .Pp |
| 876 | .It Ic force-command Ns = Ns Ar command |
| 877 | Forces the execution of |
| 878 | .Ar command |
| 879 | instead of any shell or command specified by the user when |
| 880 | the certificate is used for authentication. |
| 881 | .Pp |
| 882 | .It Ic no-agent-forwarding |
| 883 | Disable |
| 884 | .Xr ssh-agent 1 |
| 885 | forwarding (permitted by default). |
| 886 | .Pp |
| 887 | .It Ic no-port-forwarding |
| 888 | Disable port forwarding (permitted by default). |
| 889 | .Pp |
| 890 | .It Ic no-pty |
| 891 | Disable PTY allocation (permitted by default). |
| 892 | .Pp |
| 893 | .It Ic no-user-rc |
| 894 | Disable execution of |
| 895 | .Pa ~/.ssh/rc |
| 896 | by |
| 897 | .Xr sshd 8 |
| 898 | (permitted by default). |
| 899 | .Pp |
| 900 | .It Ic no-x11-forwarding |
| 901 | Disable X11 forwarding (permitted by default). |
| 902 | .Pp |
| 903 | .It Ic permit-agent-forwarding |
| 904 | Allows |
| 905 | .Xr ssh-agent 1 |
| 906 | forwarding. |
| 907 | .Pp |
| 908 | .It Ic permit-port-forwarding |
| 909 | Allows port forwarding. |
| 910 | .Pp |
| 911 | .It Ic permit-pty |
| 912 | Allows PTY allocation. |
| 913 | .Pp |
| 914 | .It Ic permit-user-rc |
| 915 | Allows execution of |
| 916 | .Pa ~/.ssh/rc |
| 917 | by |
| 918 | .Xr sshd 8 . |
| 919 | .Pp |
| 920 | .It Ic permit-X11-forwarding |
| 921 | Allows X11 forwarding. |
| 922 | .Pp |
| 923 | .It Ic no-touch-required |
| 924 | Do not require signatures made using this key require demonstration |
naddy@openbsd.org | b715fdc | 2020-01-18 21:16:43 +0000 | [diff] [blame] | 925 | of user presence (e.g. by having the user touch the authenticator). |
naddy@openbsd.org | 84911da | 2020-01-18 15:45:41 +0000 | [diff] [blame] | 926 | This option only makes sense for the FIDO authenticator algorithms |
djm@openbsd.org | 1e645fe | 2019-12-30 03:28:41 +0000 | [diff] [blame] | 927 | .Cm ecdsa-sk |
| 928 | and |
| 929 | .Cm ed25519-sk . |
| 930 | .Pp |
| 931 | .It Ic source-address Ns = Ns Ar address_list |
| 932 | Restrict the source addresses from which the certificate is considered valid. |
| 933 | The |
| 934 | .Ar address_list |
| 935 | is a comma-separated list of one or more address/netmask pairs in CIDR |
| 936 | format. |
| 937 | .El |
| 938 | .Pp |
| 939 | At present, no standard options are valid for host keys. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 940 | .Pp |
| 941 | Finally, certificates may be defined with a validity lifetime. |
| 942 | The |
| 943 | .Fl V |
| 944 | option allows specification of certificate start and end times. |
| 945 | A certificate that is presented at a time outside this range will not be |
| 946 | considered valid. |
Darren Tucker | 3ee50c5 | 2012-09-06 21:18:11 +1000 | [diff] [blame] | 947 | By default, certificates are valid from |
| 948 | .Ux |
| 949 | Epoch to the distant future. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 950 | .Pp |
| 951 | For certificates to be used for user or host authentication, the CA |
| 952 | public key must be trusted by |
| 953 | .Xr sshd 8 |
| 954 | or |
| 955 | .Xr ssh 1 . |
| 956 | Please refer to those manual pages for details. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 957 | .Sh KEY REVOCATION LISTS |
| 958 | .Nm |
| 959 | is able to manage OpenSSH format Key Revocation Lists (KRLs). |
| 960 | These binary files specify keys or certificates to be revoked using a |
Damien Miller | 1379771 | 2013-12-29 17:47:14 +1100 | [diff] [blame] | 961 | compact format, taking as little as one bit per certificate if they are being |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 962 | revoked by serial number. |
| 963 | .Pp |
| 964 | KRLs may be generated using the |
| 965 | .Fl k |
| 966 | flag. |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 967 | This option reads one or more files from the command line and generates a new |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 968 | KRL. |
| 969 | The files may either contain a KRL specification (see below) or public keys, |
| 970 | listed one per line. |
| 971 | Plain public keys are revoked by listing their hash or contents in the KRL and |
| 972 | certificates revoked by serial number or key ID (if the serial is zero or |
| 973 | not available). |
| 974 | .Pp |
| 975 | Revoking keys using a KRL specification offers explicit control over the |
| 976 | types of record used to revoke keys and may be used to directly revoke |
| 977 | certificates by serial number or key ID without having the complete original |
| 978 | certificate on hand. |
| 979 | A KRL specification consists of lines containing one of the following directives |
| 980 | followed by a colon and some directive-specific information. |
| 981 | .Bl -tag -width Ds |
Damien Miller | a0a7ee8 | 2013-01-20 22:35:06 +1100 | [diff] [blame] | 982 | .It Cm serial : Ar serial_number Ns Op - Ns Ar serial_number |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 983 | Revokes a certificate with the specified serial number. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 984 | Serial numbers are 64-bit values, not including zero and may be expressed |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 985 | in decimal, hex or octal. |
| 986 | If two serial numbers are specified separated by a hyphen, then the range |
| 987 | of serial numbers including and between each is revoked. |
| 988 | The CA key must have been specified on the |
| 989 | .Nm |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 990 | command line using the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 991 | .Fl s |
| 992 | option. |
| 993 | .It Cm id : Ar key_id |
| 994 | Revokes a certificate with the specified key ID string. |
| 995 | The CA key must have been specified on the |
| 996 | .Nm |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 997 | command line using the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 998 | .Fl s |
| 999 | option. |
| 1000 | .It Cm key : Ar public_key |
| 1001 | Revokes the specified key. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 1002 | If a certificate is listed, then it is revoked as a plain public key. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1003 | .It Cm sha1 : Ar public_key |
djm@openbsd.org | 9405c62 | 2018-09-12 01:21:34 +0000 | [diff] [blame] | 1004 | Revokes the specified key by including its SHA1 hash in the KRL. |
| 1005 | .It Cm sha256 : Ar public_key |
| 1006 | Revokes the specified key by including its SHA256 hash in the KRL. |
| 1007 | KRLs that revoke keys by SHA256 hash are not supported by OpenSSH versions |
| 1008 | prior to 7.9. |
| 1009 | .It Cm hash : Ar fingerprint |
djm@openbsd.org | f0fcd7e | 2018-09-12 06:18:59 +0000 | [diff] [blame] | 1010 | Revokes a key using a fingerprint hash, as obtained from a |
djm@openbsd.org | 9405c62 | 2018-09-12 01:21:34 +0000 | [diff] [blame] | 1011 | .Xr sshd 8 |
| 1012 | authentication log message or the |
| 1013 | .Nm |
| 1014 | .Fl l |
| 1015 | flag. |
| 1016 | Only SHA256 fingerprints are supported here and resultant KRLs are |
| 1017 | not supported by OpenSSH versions prior to 7.9. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1018 | .El |
| 1019 | .Pp |
| 1020 | KRLs may be updated using the |
| 1021 | .Fl u |
| 1022 | flag in addition to |
| 1023 | .Fl k . |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 1024 | When this option is specified, keys listed via the command line are merged into |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1025 | the KRL, adding to those already there. |
| 1026 | .Pp |
| 1027 | It is also possible, given a KRL, to test whether it revokes a particular key |
| 1028 | (or keys). |
| 1029 | The |
| 1030 | .Fl Q |
jmc@openbsd.org | 8b29008 | 2015-11-05 09:48:05 +0000 | [diff] [blame] | 1031 | flag will query an existing KRL, testing each key specified on the command line. |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 1032 | If any key listed on the command line has been revoked (or an error encountered) |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 1033 | then |
| 1034 | .Nm |
| 1035 | will exit with a non-zero exit status. |
| 1036 | A zero exit status will only be returned if no key was revoked. |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 1037 | .Sh ALLOWED SIGNERS |
| 1038 | When verifying signatures, |
| 1039 | .Nm |
| 1040 | uses a simple list of identities and keys to determine whether a signature |
| 1041 | comes from an authorized source. |
| 1042 | This "allowed signers" file uses a format patterned after the |
| 1043 | AUTHORIZED_KEYS FILE FORMAT described in |
jmc@openbsd.org | db1e6f6 | 2019-09-04 05:56:54 +0000 | [diff] [blame] | 1044 | .Xr sshd 8 . |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 1045 | Each line of the file contains the following space-separated fields: |
| 1046 | principals, options, keytype, base64-encoded key. |
| 1047 | Empty lines and lines starting with a |
| 1048 | .Ql # |
| 1049 | are ignored as comments. |
| 1050 | .Pp |
| 1051 | The principals field is a pattern-list (See PATTERNS in |
| 1052 | .Xr ssh_config 5 ) |
| 1053 | consisting of one or more comma-separated USER@DOMAIN identity patterns |
| 1054 | that are accepted for signing. |
| 1055 | When verifying, the identity presented via the |
jmc@openbsd.org | 70fc9a6 | 2019-10-22 08:50:35 +0000 | [diff] [blame] | 1056 | .Fl I |
| 1057 | option must match a principals pattern in order for the corresponding key to be |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 1058 | considered acceptable for verification. |
| 1059 | .Pp |
| 1060 | The options (if present) consist of comma-separated option specifications. |
| 1061 | No spaces are permitted, except within double quotes. |
| 1062 | The following option specifications are supported (note that option keywords |
| 1063 | are case-insensitive): |
| 1064 | .Bl -tag -width Ds |
| 1065 | .It Cm cert-authority |
| 1066 | Indicates that this key is accepted as a certificate authority (CA) and |
| 1067 | that certificates signed by this CA may be accepted for verification. |
| 1068 | .It Cm namespaces="namespace-list" |
| 1069 | Specifies a pattern-list of namespaces that are accepted for this key. |
djm@openbsd.org | d637c4a | 2019-09-03 08:35:27 +0000 | [diff] [blame] | 1070 | If this option is present, the signature namespace embedded in the |
djm@openbsd.org | 2a9c9f7 | 2019-09-03 08:34:19 +0000 | [diff] [blame] | 1071 | signature object and presented on the verification command-line must |
| 1072 | match the specified list before the key will be considered acceptable. |
| 1073 | .El |
| 1074 | .Pp |
| 1075 | When verifying signatures made by certificates, the expected principal |
| 1076 | name must match both the principals pattern in the allowed signers file and |
| 1077 | the principals embedded in the certificate itself. |
| 1078 | .Pp |
| 1079 | An example allowed signers file: |
| 1080 | .Bd -literal -offset 3n |
| 1081 | # Comments allowed at start of line |
| 1082 | user1@example.com,user2@example.com ssh-rsa AAAAX1... |
| 1083 | # A certificate authority, trusted for all principals in a domain. |
| 1084 | *@example.com cert-authority ssh-ed25519 AAAB4... |
| 1085 | # A key that is accepted only for file signing. |
| 1086 | user2@example.com namespaces="file" ssh-ed25519 AAA41... |
| 1087 | .Ed |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 1088 | .Sh ENVIRONMENT |
| 1089 | .Bl -tag -width Ds |
| 1090 | .It Ev SSH_SK_PROVIDER |
naddy@openbsd.org | 141df48 | 2019-12-21 20:22:34 +0000 | [diff] [blame] | 1091 | Specifies the path to a library used to interact with FIDO authenticators. |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 1092 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 1093 | .Sh FILES |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 1094 | .Bl -tag -width Ds -compact |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 1095 | .It Pa ~/.ssh/id_dsa |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 1096 | .It Pa ~/.ssh/id_ecdsa |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 1097 | .It Pa ~/.ssh/id_ecdsa_sk |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 1098 | .It Pa ~/.ssh/id_ed25519 |
naddy@openbsd.org | f0edda8 | 2019-11-18 23:16:49 +0000 | [diff] [blame] | 1099 | .It Pa ~/.ssh/id_ed25519_sk |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 1100 | .It Pa ~/.ssh/id_rsa |
naddy@openbsd.org | 141df48 | 2019-12-21 20:22:34 +0000 | [diff] [blame] | 1101 | Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519, |
| 1102 | authenticator-hosted Ed25519 or RSA authentication identity of the user. |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 1103 | This file should not be readable by anyone but the user. |
| 1104 | It is possible to |
| 1105 | specify a passphrase when generating the key; that passphrase will be |
Darren Tucker | 199ee6f | 2009-10-24 11:50:17 +1100 | [diff] [blame] | 1106 | used to encrypt the private part of this file using 128-bit AES. |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 1107 | This file is not automatically accessed by |
| 1108 | .Nm |
| 1109 | but it is offered as the default file for the private key. |
Ben Lindstrom | bda98b0 | 2001-07-04 03:35:24 +0000 | [diff] [blame] | 1110 | .Xr ssh 1 |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 1111 | will read this file when a login attempt is made. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 1112 | .Pp |
| 1113 | .It Pa ~/.ssh/id_dsa.pub |
| 1114 | .It Pa ~/.ssh/id_ecdsa.pub |
naddy@openbsd.org | aa4c640 | 2019-11-07 08:38:38 +0000 | [diff] [blame] | 1115 | .It Pa ~/.ssh/id_ecdsa_sk.pub |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 1116 | .It Pa ~/.ssh/id_ed25519.pub |
naddy@openbsd.org | f0edda8 | 2019-11-18 23:16:49 +0000 | [diff] [blame] | 1117 | .It Pa ~/.ssh/id_ed25519_sk.pub |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 1118 | .It Pa ~/.ssh/id_rsa.pub |
naddy@openbsd.org | 141df48 | 2019-12-21 20:22:34 +0000 | [diff] [blame] | 1119 | Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519, |
| 1120 | authenticator-hosted Ed25519 or RSA public key for authentication. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 1121 | The contents of this file should be added to |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 1122 | .Pa ~/.ssh/authorized_keys |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 1123 | on all machines |
Ben Lindstrom | 594e203 | 2001-09-12 18:35:30 +0000 | [diff] [blame] | 1124 | where the user wishes to log in using public key authentication. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 1125 | There is no need to keep the contents of this file secret. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 1126 | .Pp |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 1127 | .It Pa /etc/moduli |
| 1128 | Contains Diffie-Hellman groups used for DH-GEX. |
| 1129 | The file format is described in |
| 1130 | .Xr moduli 5 . |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1131 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 1132 | .Sh SEE ALSO |
| 1133 | .Xr ssh 1 , |
| 1134 | .Xr ssh-add 1 , |
Damien Miller | 2e8b1c8 | 1999-11-15 23:33:56 +1100 | [diff] [blame] | 1135 | .Xr ssh-agent 1 , |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 1136 | .Xr moduli 5 , |
Ben Lindstrom | 77788dc | 2001-02-10 23:10:33 +0000 | [diff] [blame] | 1137 | .Xr sshd 8 |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 1138 | .Rs |
Damien Miller | c0367fb | 2007-01-05 16:25:46 +1100 | [diff] [blame] | 1139 | .%R RFC 4716 |
| 1140 | .%T "The Secure Shell (SSH) Public Key File Format" |
| 1141 | .%D 2006 |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 1142 | .Re |
Damien Miller | f1ce505 | 2003-06-11 22:04:39 +1000 | [diff] [blame] | 1143 | .Sh AUTHORS |
| 1144 | OpenSSH is a derivative of the original and free |
| 1145 | ssh 1.2.12 release by Tatu Ylonen. |
| 1146 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, |
| 1147 | Theo de Raadt and Dug Song |
| 1148 | removed many bugs, re-added newer features and |
| 1149 | created OpenSSH. |
| 1150 | Markus Friedl contributed the support for SSH |
| 1151 | protocol versions 1.5 and 2.0. |