sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 1 | .\" $OpenBSD: ssh-keygen.1,v 1.123 2014/08/30 15:33:50 sobrado 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 | .\" |
sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 38 | .Dd $Mdocdate: August 30 2014 $ |
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 |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 43 | .Nd authentication key generation, management and conversion |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 44 | .Sh SYNOPSIS |
Damien Miller | 495dca3 | 2003-04-01 21:42:14 +1000 | [diff] [blame] | 45 | .Bk -words |
Damien Miller | bad5e03 | 2010-07-16 13:59:59 +1000 | [diff] [blame] | 46 | .Nm ssh-keygen |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 47 | .Op Fl q |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 48 | .Op Fl b Ar bits |
Damien Miller | f0858de | 2014-04-20 13:01:30 +1000 | [diff] [blame] | 49 | .Op Fl t Cm dsa | ecdsa | ed25519 | rsa | rsa1 |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 50 | .Op Fl N Ar new_passphrase |
| 51 | .Op Fl C Ar comment |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 52 | .Op Fl f Ar output_keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 53 | .Nm ssh-keygen |
| 54 | .Fl p |
| 55 | .Op Fl P Ar old_passphrase |
| 56 | .Op Fl N Ar new_passphrase |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 57 | .Op Fl f Ar keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 58 | .Nm ssh-keygen |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 59 | .Fl i |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 60 | .Op Fl m Ar key_format |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 61 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 62 | .Nm ssh-keygen |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 63 | .Fl e |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 64 | .Op Fl m Ar key_format |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 65 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 66 | .Nm ssh-keygen |
| 67 | .Fl y |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 68 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 69 | .Nm ssh-keygen |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 70 | .Fl c |
| 71 | .Op Fl P Ar passphrase |
| 72 | .Op Fl C Ar comment |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 73 | .Op Fl f Ar keyfile |
| 74 | .Nm ssh-keygen |
| 75 | .Fl l |
Ben Lindstrom | 8fd372b | 2001-03-12 03:02:17 +0000 | [diff] [blame] | 76 | .Op Fl f Ar input_keyfile |
| 77 | .Nm ssh-keygen |
| 78 | .Fl B |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 79 | .Op Fl f Ar input_keyfile |
Ben Lindstrom | a1ec4a9 | 2001-08-06 21:51:34 +0000 | [diff] [blame] | 80 | .Nm ssh-keygen |
Damien Miller | 048dc93 | 2010-02-12 09:22:04 +1100 | [diff] [blame] | 81 | .Fl D Ar pkcs11 |
Ben Lindstrom | a1ec4a9 | 2001-08-06 21:51:34 +0000 | [diff] [blame] | 82 | .Nm ssh-keygen |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 83 | .Fl F Ar hostname |
| 84 | .Op Fl f Ar known_hosts_file |
Damien Miller | 718ed50 | 2008-11-03 19:15:20 +1100 | [diff] [blame] | 85 | .Op Fl l |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 86 | .Nm ssh-keygen |
| 87 | .Fl H |
| 88 | .Op Fl f Ar known_hosts_file |
| 89 | .Nm ssh-keygen |
| 90 | .Fl R Ar hostname |
| 91 | .Op Fl f Ar known_hosts_file |
| 92 | .Nm ssh-keygen |
Damien Miller | 37876e9 | 2003-05-15 10:19:46 +1000 | [diff] [blame] | 93 | .Fl r Ar hostname |
| 94 | .Op Fl f Ar input_keyfile |
| 95 | .Op Fl g |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 96 | .Nm ssh-keygen |
| 97 | .Fl G Ar output_file |
Darren Tucker | 06930c7 | 2003-12-31 11:34:51 +1100 | [diff] [blame] | 98 | .Op Fl v |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 99 | .Op Fl b Ar bits |
| 100 | .Op Fl M Ar memory |
| 101 | .Op Fl S Ar start_point |
| 102 | .Nm ssh-keygen |
| 103 | .Fl T Ar output_file |
| 104 | .Fl f Ar input_file |
Darren Tucker | 06930c7 | 2003-12-31 11:34:51 +1100 | [diff] [blame] | 105 | .Op Fl v |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 106 | .Op Fl a Ar rounds |
Damien Miller | dfceafe | 2012-07-06 13:44:19 +1000 | [diff] [blame] | 107 | .Op Fl J Ar num_lines |
| 108 | .Op Fl j Ar start_line |
Damien Miller | 390d056 | 2011-10-18 16:05:19 +1100 | [diff] [blame] | 109 | .Op Fl K Ar checkpt |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 110 | .Op Fl W Ar generator |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 111 | .Nm ssh-keygen |
| 112 | .Fl s Ar ca_key |
| 113 | .Fl I Ar certificate_identity |
| 114 | .Op Fl h |
| 115 | .Op Fl n Ar principals |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 116 | .Op Fl O Ar option |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 117 | .Op Fl V Ar validity_interval |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 118 | .Op Fl z Ar serial_number |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 119 | .Ar |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 120 | .Nm ssh-keygen |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 121 | .Fl L |
| 122 | .Op Fl f Ar input_keyfile |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 123 | .Nm ssh-keygen |
| 124 | .Fl A |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 125 | .Nm ssh-keygen |
| 126 | .Fl k |
| 127 | .Fl f Ar krl_file |
| 128 | .Op Fl u |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 129 | .Op Fl s Ar ca_public |
| 130 | .Op Fl z Ar version_number |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 131 | .Ar |
| 132 | .Nm ssh-keygen |
| 133 | .Fl Q |
| 134 | .Fl f Ar krl_file |
| 135 | .Ar |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 136 | .Ek |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 137 | .Sh DESCRIPTION |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 138 | .Nm |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 139 | generates, manages and converts authentication keys for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 140 | .Xr ssh 1 . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 141 | .Nm |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 142 | can create RSA keys for use by SSH protocol version 1 and |
sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 143 | DSA, ECDSA, Ed25519 or RSA keys for use by SSH protocol version 2. |
Damien Miller | fbf486b | 2003-05-23 18:44:23 +1000 | [diff] [blame] | 144 | The type of key to be generated is specified with the |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 145 | .Fl t |
Damien Miller | a41c8b1 | 2002-01-22 23:05:08 +1100 | [diff] [blame] | 146 | option. |
Damien Miller | f14be5c | 2005-11-05 15:15:49 +1100 | [diff] [blame] | 147 | If invoked without any arguments, |
| 148 | .Nm |
Damien Miller | 83d0d39 | 2005-11-05 15:16:27 +1100 | [diff] [blame] | 149 | will generate an RSA key for use in SSH protocol 2 connections. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 150 | .Pp |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 151 | .Nm |
| 152 | is also used to generate groups for use in Diffie-Hellman group |
| 153 | exchange (DH-GEX). |
| 154 | See the |
| 155 | .Sx MODULI GENERATION |
| 156 | section for details. |
| 157 | .Pp |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 158 | Finally, |
| 159 | .Nm |
| 160 | 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] | 161 | given keys have been revoked by one. |
| 162 | See the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 163 | .Sx KEY REVOCATION LISTS |
| 164 | section for details. |
| 165 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 166 | Normally each user wishing to use SSH |
Damien Miller | eb8b60e | 2010-08-31 22:41:14 +1000 | [diff] [blame] | 167 | with public key authentication runs this once to create the authentication |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 168 | key in |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 169 | .Pa ~/.ssh/identity , |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 170 | .Pa ~/.ssh/id_dsa , |
Damien Miller | eb8b60e | 2010-08-31 22:41:14 +1000 | [diff] [blame] | 171 | .Pa ~/.ssh/id_ecdsa , |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 172 | .Pa ~/.ssh/id_ed25519 |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 173 | or |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 174 | .Pa ~/.ssh/id_rsa . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 175 | Additionally, the system administrator may use this to generate host keys, |
| 176 | as seen in |
| 177 | .Pa /etc/rc . |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 178 | .Pp |
| 179 | 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] | 180 | to store the private key. |
| 181 | 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] | 182 | .Dq .pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 183 | appended. |
| 184 | The program also asks for a passphrase. |
| 185 | The passphrase may be empty to indicate no passphrase |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 186 | (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] | 187 | arbitrary length. |
Ben Lindstrom | 4e366d5 | 2001-12-06 16:43:21 +0000 | [diff] [blame] | 188 | A passphrase is similar to a password, except it can be a phrase with a |
| 189 | series of words, punctuation, numbers, whitespace, or any string of |
| 190 | characters you want. |
| 191 | Good passphrases are 10-30 characters long, are |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 192 | not simple sentences or otherwise easily guessable (English |
Ben Lindstrom | 2a097a4 | 2001-06-09 01:13:40 +0000 | [diff] [blame] | 193 | 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] | 194 | passphrases), and contain a mix of upper and lowercase letters, |
| 195 | numbers, and non-alphanumeric characters. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 196 | The passphrase can be changed later by using the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 197 | .Fl p |
| 198 | option. |
| 199 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 200 | There is no way to recover a lost passphrase. |
Damien Miller | 085c90f | 2011-05-05 14:15:33 +1000 | [diff] [blame] | 201 | If the passphrase is lost or forgotten, a new key must be generated |
| 202 | and the corresponding public key copied to other machines. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 203 | .Pp |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 204 | For RSA1 keys, |
| 205 | there is also a comment field in the key file that is only for |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 206 | convenience to the user to help identify the key. |
| 207 | The comment can tell what the key is for, or whatever is useful. |
| 208 | The comment is initialized to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 209 | .Dq user@host |
| 210 | when the key is created, but can be changed using the |
| 211 | .Fl c |
| 212 | option. |
| 213 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 214 | After a key is generated, instructions below detail where the keys |
| 215 | should be placed to be activated. |
| 216 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 217 | The options are as follows: |
| 218 | .Bl -tag -width Ds |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 219 | .It Fl A |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 220 | For each of the key types (rsa1, rsa, dsa, ecdsa and ed25519) |
| 221 | for which host keys |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 222 | do not exist, generate the host keys with the default key file path, |
| 223 | an empty passphrase, default bits for the key type, and default comment. |
Damien Miller | 3ca1eb3 | 2011-05-05 14:13:50 +1000 | [diff] [blame] | 224 | This is used by |
Damien Miller | 58f1baf | 2011-05-05 14:06:15 +1000 | [diff] [blame] | 225 | .Pa /etc/rc |
| 226 | to generate new host keys. |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 227 | .It Fl a Ar rounds |
| 228 | When saving a new-format private key (i.e. an ed25519 key or any SSH protocol |
| 229 | 2 key when the |
| 230 | .Fl o |
| 231 | flag is set), this option specifies the number of KDF (key derivation function) |
| 232 | rounds used. |
| 233 | Higher numbers result in slower passphrase verification and increased |
| 234 | resistance to brute-force password cracking (should the keys be stolen). |
| 235 | .Pp |
| 236 | When screening DH-GEX candidates ( |
| 237 | using the |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 238 | .Fl T |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 239 | command). |
| 240 | This option specifies the number of primality tests to perform. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 241 | .It Fl B |
| 242 | Show the bubblebabble digest of specified private or public key file. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 243 | .It Fl b Ar bits |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 244 | Specifies the number of bits in the key to create. |
Darren Tucker | 9f64733 | 2005-11-28 16:41:46 +1100 | [diff] [blame] | 245 | For RSA keys, the minimum size is 768 bits and the default is 2048 bits. |
Damien Miller | ac7ef6a | 2005-06-16 13:19:06 +1000 | [diff] [blame] | 246 | Generally, 2048 bits is considered sufficient. |
Darren Tucker | 9f64733 | 2005-11-28 16:41:46 +1100 | [diff] [blame] | 247 | 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] | 248 | For ECDSA keys, the |
| 249 | .Fl b |
Damien Miller | 6232a16 | 2011-09-22 21:36:00 +1000 | [diff] [blame] | 250 | flag determines the key length by selecting from one of three elliptic |
Damien Miller | ad21032 | 2011-05-05 14:15:54 +1000 | [diff] [blame] | 251 | curve sizes: 256, 384 or 521 bits. |
| 252 | Attempting to use bit lengths other than these three values for ECDSA keys |
| 253 | will fail. |
sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 254 | Ed25519 keys have a fixed length and the |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 255 | .Fl b |
| 256 | flag will be ignored. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 257 | .It Fl C Ar comment |
| 258 | Provides a new comment. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 259 | .It Fl c |
| 260 | Requests changing the comment in the private and public key files. |
Damien Miller | eb5fec6 | 2001-11-12 10:52:44 +1100 | [diff] [blame] | 261 | This operation is only supported for RSA1 keys. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 262 | The program will prompt for the file containing the private keys, for |
Ben Lindstrom | aafff9c | 2001-05-06 03:01:02 +0000 | [diff] [blame] | 263 | the passphrase if the key has one, and for the new comment. |
Damien Miller | 7ea845e | 2010-02-12 09:21:02 +1100 | [diff] [blame] | 264 | .It Fl D Ar pkcs11 |
Damien Miller | a761844 | 2010-02-12 09:26:02 +1100 | [diff] [blame] | 265 | Download the RSA public keys provided by the PKCS#11 shared library |
| 266 | .Ar pkcs11 . |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 267 | When used in combination with |
| 268 | .Fl s , |
| 269 | this option indicates that a CA key resides in a PKCS#11 token (see the |
| 270 | .Sx CERTIFICATES |
| 271 | section for details). |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 272 | .It Fl e |
Ben Lindstrom | 46c264f | 2001-04-24 16:56:58 +0000 | [diff] [blame] | 273 | This option will read a private or public OpenSSH key file and |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 274 | print to stdout the key in one of the formats specified by the |
| 275 | .Fl m |
| 276 | option. |
| 277 | The default export format is |
| 278 | .Dq RFC4716 . |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 279 | This option allows exporting OpenSSH keys for use by other programs, including |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 280 | several commercial SSH implementations. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 281 | .It Fl F Ar hostname |
| 282 | Search for the specified |
| 283 | .Ar hostname |
| 284 | in a |
| 285 | .Pa known_hosts |
| 286 | file, listing any occurrences found. |
| 287 | This option is useful to find hashed host names or addresses and may also be |
| 288 | used in conjunction with the |
| 289 | .Fl H |
| 290 | option to print found keys in a hashed format. |
| 291 | .It Fl f Ar filename |
| 292 | Specifies the filename of the key file. |
| 293 | .It Fl G Ar output_file |
| 294 | Generate candidate primes for DH-GEX. |
| 295 | These primes must be screened for |
| 296 | safety (using the |
| 297 | .Fl T |
| 298 | option) before use. |
Damien Miller | 37876e9 | 2003-05-15 10:19:46 +1000 | [diff] [blame] | 299 | .It Fl g |
Darren Tucker | 0b42e6d | 2004-08-13 21:22:40 +1000 | [diff] [blame] | 300 | Use generic DNS format when printing fingerprint resource records using the |
Darren Tucker | 6e37037 | 2004-08-13 21:23:25 +1000 | [diff] [blame] | 301 | .Fl r |
Darren Tucker | 0b42e6d | 2004-08-13 21:22:40 +1000 | [diff] [blame] | 302 | command. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 303 | .It Fl H |
| 304 | Hash a |
| 305 | .Pa known_hosts |
Darren Tucker | da1adbc | 2005-03-14 23:15:58 +1100 | [diff] [blame] | 306 | file. |
| 307 | This replaces all hostnames and addresses with hashed representations |
| 308 | within the specified file; the original content is moved to a file with |
| 309 | a .old suffix. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 310 | These hashes may be used normally by |
| 311 | .Nm ssh |
| 312 | and |
| 313 | .Nm sshd , |
| 314 | but they do not reveal identifying information should the file's contents |
| 315 | be disclosed. |
| 316 | This option will not modify existing hashed hostnames and is therefore safe |
| 317 | to use on files that mix hashed and non-hashed names. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 318 | .It Fl h |
| 319 | When signing a key, create a host certificate instead of a user |
| 320 | certificate. |
| 321 | Please see the |
| 322 | .Sx CERTIFICATES |
| 323 | section for details. |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 324 | .It Fl I Ar certificate_identity |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 325 | Specify the key identity when signing a public key. |
| 326 | Please see the |
| 327 | .Sx CERTIFICATES |
| 328 | section for details. |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 329 | .It Fl i |
| 330 | This option will read an unencrypted private (or public) key file |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 331 | in the format specified by the |
| 332 | .Fl m |
| 333 | option and print an OpenSSH compatible private |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 334 | (or public) key to stdout. |
Damien Miller | 43b156c | 2014-04-20 13:23:03 +1000 | [diff] [blame] | 335 | This option allows importing keys from other software, including several |
| 336 | commercial SSH implementations. |
| 337 | The default import format is |
| 338 | .Dq RFC4716 . |
Damien Miller | dfceafe | 2012-07-06 13:44:19 +1000 | [diff] [blame] | 339 | .It Fl J Ar num_lines |
| 340 | Exit after screening the specified number of lines |
| 341 | while performing DH candidate screening using the |
| 342 | .Fl T |
| 343 | option. |
| 344 | .It Fl j Ar start_line |
| 345 | Start screening at the specified line number |
| 346 | while performing DH candidate screening using the |
| 347 | .Fl T |
| 348 | option. |
Damien Miller | 390d056 | 2011-10-18 16:05:19 +1100 | [diff] [blame] | 349 | .It Fl K Ar checkpt |
| 350 | Write the last line processed to the file |
| 351 | .Ar checkpt |
| 352 | while performing DH candidate screening using the |
| 353 | .Fl T |
| 354 | option. |
| 355 | This will be used to skip lines in the input file that have already been |
| 356 | processed if the job is restarted. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 357 | .It Fl k |
| 358 | Generate a KRL file. |
| 359 | In this mode, |
| 360 | .Nm |
| 361 | will generate a KRL file at the location specified via the |
| 362 | .Fl f |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 363 | flag that revokes every key or certificate presented on the command line. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 364 | Keys/certificates to be revoked may be specified by public key file or |
| 365 | using the format described in the |
| 366 | .Sx KEY REVOCATION LISTS |
| 367 | section. |
Damien Miller | f2b70ca | 2010-03-05 07:39:35 +1100 | [diff] [blame] | 368 | .It Fl L |
| 369 | Prints the contents of a certificate. |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 370 | .It Fl l |
Darren Tucker | 35c4553 | 2008-06-13 04:43:15 +1000 | [diff] [blame] | 371 | Show fingerprint of specified public key file. |
Damien Miller | eb5fec6 | 2001-11-12 10:52:44 +1100 | [diff] [blame] | 372 | Private RSA1 keys are also supported. |
| 373 | For RSA and DSA keys |
| 374 | .Nm |
Darren Tucker | f09e825 | 2008-06-13 05:18:03 +1000 | [diff] [blame] | 375 | tries to find the matching public key file and prints its fingerprint. |
| 376 | If combined with |
| 377 | .Fl v , |
| 378 | an ASCII art representation of the key is supplied with the fingerprint. |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 379 | .It Fl M Ar memory |
| 380 | Specify the amount of memory to use (in megabytes) when generating |
| 381 | candidate moduli for DH-GEX. |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 382 | .It Fl m Ar key_format |
| 383 | Specify a key format for the |
| 384 | .Fl i |
| 385 | (import) or |
| 386 | .Fl e |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 387 | (export) conversion options. |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 388 | The supported key formats are: |
| 389 | .Dq RFC4716 |
Damien Miller | ea72728 | 2010-07-02 13:35:34 +1000 | [diff] [blame] | 390 | (RFC 4716/SSH2 public or private key), |
Damien Miller | 44b2504 | 2010-07-02 13:35:01 +1000 | [diff] [blame] | 391 | .Dq PKCS8 |
| 392 | (PEM PKCS8 public key) |
| 393 | or |
| 394 | .Dq PEM |
| 395 | (PEM public key). |
| 396 | The default conversion format is |
| 397 | .Dq RFC4716 . |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 398 | .It Fl N Ar new_passphrase |
| 399 | Provides the new passphrase. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 400 | .It Fl n Ar principals |
| 401 | Specify one or more principals (user or host names) to be included in |
| 402 | a certificate when signing a key. |
| 403 | Multiple principals may be specified, separated by commas. |
| 404 | Please see the |
| 405 | .Sx CERTIFICATES |
| 406 | section for details. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 407 | .It Fl O Ar option |
| 408 | Specify a certificate option when signing a key. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 409 | This option may be specified multiple times. |
| 410 | Please see the |
| 411 | .Sx CERTIFICATES |
| 412 | section for details. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 413 | The options that are valid for user certificates are: |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 414 | .Bl -tag -width Ds |
Damien Miller | c59e244 | 2010-03-22 05:50:31 +1100 | [diff] [blame] | 415 | .It Ic clear |
| 416 | Clear all enabled permissions. |
| 417 | This is useful for clearing the default set of permissions so permissions may |
| 418 | be added individually. |
| 419 | .It Ic force-command Ns = Ns Ar command |
| 420 | Forces the execution of |
| 421 | .Ar command |
| 422 | instead of any shell or command specified by the user when |
| 423 | the certificate is used for authentication. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 424 | .It Ic no-agent-forwarding |
| 425 | Disable |
| 426 | .Xr ssh-agent 1 |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 427 | forwarding (permitted by default). |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 428 | .It Ic no-port-forwarding |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 429 | Disable port forwarding (permitted by default). |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 430 | .It Ic no-pty |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 431 | Disable PTY allocation (permitted by default). |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 432 | .It Ic no-user-rc |
| 433 | Disable execution of |
| 434 | .Pa ~/.ssh/rc |
| 435 | by |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 436 | .Xr sshd 8 |
| 437 | (permitted by default). |
Damien Miller | c59e244 | 2010-03-22 05:50:31 +1100 | [diff] [blame] | 438 | .It Ic no-x11-forwarding |
| 439 | Disable X11 forwarding (permitted by default). |
Damien Miller | 081c976 | 2010-03-08 11:30:00 +1100 | [diff] [blame] | 440 | .It Ic permit-agent-forwarding |
| 441 | Allows |
| 442 | .Xr ssh-agent 1 |
| 443 | forwarding. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 444 | .It Ic permit-port-forwarding |
| 445 | Allows port forwarding. |
| 446 | .It Ic permit-pty |
| 447 | Allows PTY allocation. |
| 448 | .It Ic permit-user-rc |
| 449 | Allows execution of |
| 450 | .Pa ~/.ssh/rc |
| 451 | by |
| 452 | .Xr sshd 8 . |
Damien Miller | c59e244 | 2010-03-22 05:50:31 +1100 | [diff] [blame] | 453 | .It Ic permit-x11-forwarding |
| 454 | Allows X11 forwarding. |
| 455 | .It Ic source-address Ns = Ns Ar address_list |
Damien Miller | 77497e1 | 2010-03-22 05:50:51 +1100 | [diff] [blame] | 456 | Restrict the source addresses from which the certificate is considered valid. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 457 | The |
| 458 | .Ar address_list |
| 459 | is a comma-separated list of one or more address/netmask pairs in CIDR |
| 460 | format. |
| 461 | .El |
| 462 | .Pp |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 463 | At present, no options are valid for host keys. |
Damien Miller | 4f752cf | 2013-12-18 17:45:35 +1100 | [diff] [blame] | 464 | .It Fl o |
| 465 | Causes |
| 466 | .Nm |
| 467 | to save SSH protocol 2 private keys using the new OpenSSH format rather than |
| 468 | the more compatible PEM format. |
| 469 | The new format has increased resistance to brute-force password cracking |
| 470 | but is not supported by versions of OpenSSH prior to 6.5. |
| 471 | Ed25519 keys always use the new private key format. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 472 | .It Fl P Ar passphrase |
| 473 | Provides the (old) passphrase. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 474 | .It Fl p |
| 475 | Requests changing the passphrase of a private key file instead of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 476 | creating a new private key. |
| 477 | The program will prompt for the file |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 478 | containing the private key, for the old passphrase, and twice for the |
| 479 | new passphrase. |
Damien Miller | 072fdcd | 2013-01-20 22:34:04 +1100 | [diff] [blame] | 480 | .It Fl Q |
| 481 | Test whether keys have been revoked in a KRL. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 482 | .It Fl q |
| 483 | Silence |
| 484 | .Nm ssh-keygen . |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 485 | .It Fl R Ar hostname |
| 486 | Removes all keys belonging to |
| 487 | .Ar hostname |
Damien Miller | 4c9c6fd | 2005-03-02 12:03:43 +1100 | [diff] [blame] | 488 | from a |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 489 | .Pa known_hosts |
| 490 | file. |
Damien Miller | 4c9c6fd | 2005-03-02 12:03:43 +1100 | [diff] [blame] | 491 | This option is useful to delete hashed hosts (see the |
Damien Miller | 4b42d7f | 2005-03-01 21:48:35 +1100 | [diff] [blame] | 492 | .Fl H |
| 493 | option above). |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 494 | .It Fl r Ar hostname |
| 495 | Print the SSHFP fingerprint resource record named |
| 496 | .Ar hostname |
| 497 | for the specified public key file. |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 498 | .It Fl S Ar start |
| 499 | Specify start point (in hex) when generating candidate moduli for DH-GEX. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 500 | .It Fl s Ar ca_key |
| 501 | Certify (sign) a public key using the specified CA key. |
| 502 | Please see the |
| 503 | .Sx CERTIFICATES |
| 504 | section for details. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 505 | .Pp |
| 506 | When generating a KRL, |
| 507 | .Fl s |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 508 | 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] | 509 | by key ID or serial number. |
| 510 | See the |
| 511 | .Sx KEY REVOCATION LISTS |
| 512 | section for details. |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 513 | .It Fl T Ar output_file |
| 514 | Test DH group exchange candidate primes (generated using the |
| 515 | .Fl G |
| 516 | option) for safety. |
Damien Miller | f0858de | 2014-04-20 13:01:30 +1000 | [diff] [blame] | 517 | .It Fl t Cm dsa | ecdsa | ed25519 | rsa | rsa1 |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 518 | Specifies the type of key to create. |
| 519 | The possible values are |
| 520 | .Dq rsa1 |
| 521 | for protocol version 1 and |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 522 | .Dq dsa , |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 523 | .Dq ecdsa , |
| 524 | .Dq ed25519 , |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 525 | or |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 526 | .Dq rsa |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 527 | for protocol version 2. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 528 | .It Fl u |
| 529 | Update a KRL. |
| 530 | When specified with |
| 531 | .Fl k , |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 532 | 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] | 533 | a new KRL being created. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 534 | .It Fl V Ar validity_interval |
| 535 | Specify a validity interval when signing a certificate. |
| 536 | A validity interval may consist of a single time, indicating that the |
| 537 | certificate is valid beginning now and expiring at that time, or may consist |
| 538 | of two times separated by a colon to indicate an explicit time interval. |
| 539 | The start time may be specified as a date in YYYYMMDD format, a time |
| 540 | in YYYYMMDDHHMMSS format or a relative time (to the current time) consisting |
| 541 | of a minus sign followed by a relative time in the format described in the |
Damien Miller | fecfd11 | 2013-07-18 16:11:50 +1000 | [diff] [blame] | 542 | TIME FORMATS section of |
Damien Miller | 77497e1 | 2010-03-22 05:50:51 +1100 | [diff] [blame] | 543 | .Xr sshd_config 5 . |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 544 | The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMMSS time or |
| 545 | a relative time starting with a plus character. |
| 546 | .Pp |
| 547 | For example: |
| 548 | .Dq +52w1d |
| 549 | (valid from now to 52 weeks and one day from now), |
| 550 | .Dq -4w:+4w |
| 551 | (valid from four weeks ago to four weeks from now), |
| 552 | .Dq 20100101123000:20110101123000 |
| 553 | (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011), |
| 554 | .Dq -1d:20110101 |
| 555 | (valid from yesterday to midnight, January 1st, 2011). |
Darren Tucker | 06930c7 | 2003-12-31 11:34:51 +1100 | [diff] [blame] | 556 | .It Fl v |
| 557 | Verbose mode. |
| 558 | Causes |
| 559 | .Nm |
| 560 | to print debugging messages about its progress. |
| 561 | This is helpful for debugging moduli generation. |
| 562 | Multiple |
| 563 | .Fl v |
| 564 | options increase the verbosity. |
| 565 | The maximum is 3. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 566 | .It Fl W Ar generator |
| 567 | Specify desired generator when testing candidate moduli for DH-GEX. |
| 568 | .It Fl y |
| 569 | This option will read a private |
| 570 | OpenSSH format file and print an OpenSSH public key to stdout. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 571 | .It Fl z Ar serial_number |
| 572 | Specifies a serial number to be embedded in the certificate to distinguish |
| 573 | this certificate from others from the same CA. |
| 574 | The default serial number is zero. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 575 | .Pp |
| 576 | When generating a KRL, the |
| 577 | .Fl z |
| 578 | flag is used to specify a KRL version number. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 579 | .El |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 580 | .Sh MODULI GENERATION |
| 581 | .Nm |
| 582 | may be used to generate groups for the Diffie-Hellman Group Exchange |
| 583 | (DH-GEX) protocol. |
| 584 | Generating these groups is a two-step process: first, candidate |
| 585 | primes are generated using a fast, but memory intensive process. |
| 586 | These candidate primes are then tested for suitability (a CPU-intensive |
| 587 | process). |
| 588 | .Pp |
| 589 | Generation of primes is performed using the |
| 590 | .Fl G |
| 591 | option. |
| 592 | The desired length of the primes may be specified by the |
| 593 | .Fl b |
| 594 | option. |
| 595 | For example: |
| 596 | .Pp |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 597 | .Dl # ssh-keygen -G moduli-2048.candidates -b 2048 |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 598 | .Pp |
| 599 | By default, the search for primes begins at a random point in the |
| 600 | desired length range. |
| 601 | This may be overridden using the |
| 602 | .Fl S |
| 603 | option, which specifies a different start point (in hex). |
| 604 | .Pp |
Damien Miller | dfceafe | 2012-07-06 13:44:19 +1000 | [diff] [blame] | 605 | 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] | 606 | suitability. |
| 607 | This may be performed using the |
| 608 | .Fl T |
| 609 | option. |
| 610 | In this mode |
| 611 | .Nm |
| 612 | will read candidates from standard input (or a file specified using the |
| 613 | .Fl f |
| 614 | option). |
| 615 | For example: |
| 616 | .Pp |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 617 | .Dl # ssh-keygen -T moduli-2048 -f moduli-2048.candidates |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 618 | .Pp |
| 619 | By default, each candidate will be subjected to 100 primality tests. |
| 620 | This may be overridden using the |
| 621 | .Fl a |
| 622 | option. |
| 623 | The DH generator value will be chosen automatically for the |
| 624 | prime under consideration. |
| 625 | If a specific generator is desired, it may be requested using the |
| 626 | .Fl W |
| 627 | option. |
Damien Miller | 265d309 | 2005-03-02 12:05:06 +1100 | [diff] [blame] | 628 | Valid generator values are 2, 3, and 5. |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 629 | .Pp |
| 630 | Screened DH groups may be installed in |
| 631 | .Pa /etc/moduli . |
| 632 | It is important that this file contains moduli of a range of bit lengths and |
| 633 | that both ends of a connection share common moduli. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 634 | .Sh CERTIFICATES |
| 635 | .Nm |
| 636 | supports signing of keys to produce certificates that may be used for |
| 637 | user or host authentication. |
| 638 | Certificates consist of a public key, some identity information, zero or |
Damien Miller | 1f18142 | 2010-04-18 08:08:03 +1000 | [diff] [blame] | 639 | more principal (user or host) names and a set of options that |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 640 | are signed by a Certification Authority (CA) key. |
| 641 | Clients or servers may then trust only the CA key and verify its signature |
| 642 | on a certificate rather than trusting many user/host keys. |
| 643 | Note that OpenSSH certificates are a different, and much simpler, format to |
| 644 | the X.509 certificates used in |
| 645 | .Xr ssl 8 . |
| 646 | .Pp |
| 647 | .Nm |
| 648 | supports two types of certificates: user and host. |
| 649 | User certificates authenticate users to servers, whereas host certificates |
Damien Miller | 15f5b56 | 2010-03-03 10:25:21 +1100 | [diff] [blame] | 650 | authenticate server hosts to users. |
| 651 | To generate a user certificate: |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 652 | .Pp |
| 653 | .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub |
| 654 | .Pp |
| 655 | The resultant certificate will be placed in |
Damien Miller | 1b61a28 | 2010-03-22 05:55:06 +1100 | [diff] [blame] | 656 | .Pa /path/to/user_key-cert.pub . |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 657 | A host certificate requires the |
| 658 | .Fl h |
| 659 | option: |
| 660 | .Pp |
| 661 | .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub |
| 662 | .Pp |
| 663 | The host certificate will be output to |
Damien Miller | 1b61a28 | 2010-03-22 05:55:06 +1100 | [diff] [blame] | 664 | .Pa /path/to/host_key-cert.pub . |
Damien Miller | 757f34e | 2010-08-05 13:05:31 +1000 | [diff] [blame] | 665 | .Pp |
| 666 | It is possible to sign using a CA key stored in a PKCS#11 token by |
| 667 | providing the token library using |
| 668 | .Fl D |
| 669 | and identifying the CA key by providing its public half as an argument |
| 670 | to |
| 671 | .Fl s : |
| 672 | .Pp |
| 673 | .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id host_key.pub |
| 674 | .Pp |
| 675 | In all cases, |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 676 | .Ar key_id |
| 677 | is a "key identifier" that is logged by the server when the certificate |
| 678 | is used for authentication. |
| 679 | .Pp |
| 680 | Certificates may be limited to be valid for a set of principal (user/host) |
| 681 | names. |
| 682 | By default, generated certificates are valid for all users or hosts. |
| 683 | To generate a certificate for a specified set of principals: |
| 684 | .Pp |
| 685 | .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub |
Damien Miller | 5a5d94b | 2010-03-22 05:57:49 +1100 | [diff] [blame] | 686 | .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub" |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 687 | .Pp |
| 688 | Additional limitations on the validity and use of user certificates may |
Damien Miller | 1f18142 | 2010-04-18 08:08:03 +1000 | [diff] [blame] | 689 | be specified through certificate options. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 690 | A certificate option may disable features of the SSH session, may be |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 691 | valid only when presented from particular source addresses or may |
| 692 | force the use of a specific command. |
Damien Miller | 4e270b0 | 2010-04-16 15:56:21 +1000 | [diff] [blame] | 693 | For a list of valid certificate options, see the documentation for the |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 694 | .Fl O |
| 695 | option above. |
| 696 | .Pp |
| 697 | Finally, certificates may be defined with a validity lifetime. |
| 698 | The |
| 699 | .Fl V |
| 700 | option allows specification of certificate start and end times. |
| 701 | A certificate that is presented at a time outside this range will not be |
| 702 | considered valid. |
Darren Tucker | 3ee50c5 | 2012-09-06 21:18:11 +1000 | [diff] [blame] | 703 | By default, certificates are valid from |
| 704 | .Ux |
| 705 | Epoch to the distant future. |
Damien Miller | 0a80ca1 | 2010-02-27 07:55:05 +1100 | [diff] [blame] | 706 | .Pp |
| 707 | For certificates to be used for user or host authentication, the CA |
| 708 | public key must be trusted by |
| 709 | .Xr sshd 8 |
| 710 | or |
| 711 | .Xr ssh 1 . |
| 712 | Please refer to those manual pages for details. |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 713 | .Sh KEY REVOCATION LISTS |
| 714 | .Nm |
| 715 | is able to manage OpenSSH format Key Revocation Lists (KRLs). |
| 716 | These binary files specify keys or certificates to be revoked using a |
Damien Miller | 1379771 | 2013-12-29 17:47:14 +1100 | [diff] [blame] | 717 | 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] | 718 | revoked by serial number. |
| 719 | .Pp |
| 720 | KRLs may be generated using the |
| 721 | .Fl k |
| 722 | flag. |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 723 | 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] | 724 | KRL. |
| 725 | The files may either contain a KRL specification (see below) or public keys, |
| 726 | listed one per line. |
| 727 | Plain public keys are revoked by listing their hash or contents in the KRL and |
| 728 | certificates revoked by serial number or key ID (if the serial is zero or |
| 729 | not available). |
| 730 | .Pp |
| 731 | Revoking keys using a KRL specification offers explicit control over the |
| 732 | types of record used to revoke keys and may be used to directly revoke |
| 733 | certificates by serial number or key ID without having the complete original |
| 734 | certificate on hand. |
| 735 | A KRL specification consists of lines containing one of the following directives |
| 736 | followed by a colon and some directive-specific information. |
| 737 | .Bl -tag -width Ds |
Damien Miller | a0a7ee8 | 2013-01-20 22:35:06 +1100 | [diff] [blame] | 738 | .It Cm serial : Ar serial_number Ns Op - Ns Ar serial_number |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 739 | Revokes a certificate with the specified serial number. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 740 | 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] | 741 | in decimal, hex or octal. |
| 742 | If two serial numbers are specified separated by a hyphen, then the range |
| 743 | of serial numbers including and between each is revoked. |
| 744 | The CA key must have been specified on the |
| 745 | .Nm |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 746 | command line using the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 747 | .Fl s |
| 748 | option. |
| 749 | .It Cm id : Ar key_id |
| 750 | Revokes a certificate with the specified key ID string. |
| 751 | The CA key must have been specified on the |
| 752 | .Nm |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 753 | command line using the |
Damien Miller | f3747bf | 2013-01-18 11:44:04 +1100 | [diff] [blame] | 754 | .Fl s |
| 755 | option. |
| 756 | .It Cm key : Ar public_key |
| 757 | Revokes the specified key. |
Damien Miller | ac5542b | 2013-01-20 22:33:02 +1100 | [diff] [blame] | 758 | 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] | 759 | .It Cm sha1 : Ar public_key |
| 760 | Revokes the specified key by its SHA1 hash. |
| 761 | .El |
| 762 | .Pp |
| 763 | KRLs may be updated using the |
| 764 | .Fl u |
| 765 | flag in addition to |
| 766 | .Fl k . |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 767 | 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] | 768 | the KRL, adding to those already there. |
| 769 | .Pp |
| 770 | It is also possible, given a KRL, to test whether it revokes a particular key |
| 771 | (or keys). |
| 772 | The |
| 773 | .Fl Q |
| 774 | flag will query an existing KRL, testing each key specified on the commandline. |
Damien Miller | 881a7a2 | 2013-01-20 22:34:46 +1100 | [diff] [blame] | 775 | 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] | 776 | then |
| 777 | .Nm |
| 778 | will exit with a non-zero exit status. |
| 779 | A zero exit status will only be returned if no key was revoked. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 780 | .Sh FILES |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 781 | .Bl -tag -width Ds -compact |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 782 | .It Pa ~/.ssh/identity |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 783 | Contains the protocol version 1 RSA authentication identity of the user. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 784 | This file should not be readable by anyone but the user. |
| 785 | It is possible to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 786 | specify a passphrase when generating the key; that passphrase will be |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 787 | used to encrypt the private part of this file using 3DES. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 788 | This file is not automatically accessed by |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 789 | .Nm |
| 790 | but it is offered as the default file for the private key. |
Ben Lindstrom | bda98b0 | 2001-07-04 03:35:24 +0000 | [diff] [blame] | 791 | .Xr ssh 1 |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 792 | will read this file when a login attempt is made. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 793 | .Pp |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 794 | .It Pa ~/.ssh/identity.pub |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 795 | Contains the protocol version 1 RSA public key for authentication. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 796 | The contents of this file should be added to |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 797 | .Pa ~/.ssh/authorized_keys |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 798 | on all machines |
Ben Lindstrom | 594e203 | 2001-09-12 18:35:30 +0000 | [diff] [blame] | 799 | where the user wishes to log in using RSA authentication. |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 800 | There is no need to keep the contents of this file secret. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 801 | .Pp |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 802 | .It Pa ~/.ssh/id_dsa |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 803 | .It Pa ~/.ssh/id_ecdsa |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 804 | .It Pa ~/.ssh/id_ed25519 |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 805 | .It Pa ~/.ssh/id_rsa |
sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 806 | Contains the protocol version 2 DSA, ECDSA, Ed25519 or RSA |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 807 | authentication identity of the user. |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 808 | This file should not be readable by anyone but the user. |
| 809 | It is possible to |
| 810 | specify a passphrase when generating the key; that passphrase will be |
Darren Tucker | 199ee6f | 2009-10-24 11:50:17 +1100 | [diff] [blame] | 811 | 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] | 812 | This file is not automatically accessed by |
| 813 | .Nm |
| 814 | but it is offered as the default file for the private key. |
Ben Lindstrom | bda98b0 | 2001-07-04 03:35:24 +0000 | [diff] [blame] | 815 | .Xr ssh 1 |
Ben Lindstrom | 18a82ac | 2001-04-11 15:59:35 +0000 | [diff] [blame] | 816 | will read this file when a login attempt is made. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 817 | .Pp |
| 818 | .It Pa ~/.ssh/id_dsa.pub |
| 819 | .It Pa ~/.ssh/id_ecdsa.pub |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 820 | .It Pa ~/.ssh/id_ed25519.pub |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 821 | .It Pa ~/.ssh/id_rsa.pub |
sobrado@openbsd.org | f70b22b | 2014-08-30 15:33:50 +0000 | [diff] [blame] | 822 | Contains the protocol version 2 DSA, ECDSA, Ed25519 or RSA |
Damien Miller | 8ba0ead | 2013-12-18 17:46:27 +1100 | [diff] [blame] | 823 | public key for authentication. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 824 | The contents of this file should be added to |
Damien Miller | 167ea5d | 2005-05-26 12:04:02 +1000 | [diff] [blame] | 825 | .Pa ~/.ssh/authorized_keys |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 826 | on all machines |
Ben Lindstrom | 594e203 | 2001-09-12 18:35:30 +0000 | [diff] [blame] | 827 | where the user wishes to log in using public key authentication. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 828 | There is no need to keep the contents of this file secret. |
Damien Miller | 6186bbc | 2010-09-24 22:00:54 +1000 | [diff] [blame] | 829 | .Pp |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 830 | .It Pa /etc/moduli |
| 831 | Contains Diffie-Hellman groups used for DH-GEX. |
| 832 | The file format is described in |
| 833 | .Xr moduli 5 . |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 834 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 835 | .Sh SEE ALSO |
| 836 | .Xr ssh 1 , |
| 837 | .Xr ssh-add 1 , |
Damien Miller | 2e8b1c8 | 1999-11-15 23:33:56 +1100 | [diff] [blame] | 838 | .Xr ssh-agent 1 , |
Darren Tucker | 019cefe | 2003-08-02 22:40:07 +1000 | [diff] [blame] | 839 | .Xr moduli 5 , |
Ben Lindstrom | 77788dc | 2001-02-10 23:10:33 +0000 | [diff] [blame] | 840 | .Xr sshd 8 |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 841 | .Rs |
Damien Miller | c0367fb | 2007-01-05 16:25:46 +1100 | [diff] [blame] | 842 | .%R RFC 4716 |
| 843 | .%T "The Secure Shell (SSH) Public Key File Format" |
| 844 | .%D 2006 |
Ben Lindstrom | 5a70782 | 2001-04-22 17:15:46 +0000 | [diff] [blame] | 845 | .Re |
Damien Miller | f1ce505 | 2003-06-11 22:04:39 +1000 | [diff] [blame] | 846 | .Sh AUTHORS |
| 847 | OpenSSH is a derivative of the original and free |
| 848 | ssh 1.2.12 release by Tatu Ylonen. |
| 849 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, |
| 850 | Theo de Raadt and Dug Song |
| 851 | removed many bugs, re-added newer features and |
| 852 | created OpenSSH. |
| 853 | Markus Friedl contributed the support for SSH |
| 854 | protocol versions 1.5 and 2.0. |