Ben Lindstrom | 7ab5117 | 2001-03-05 05:13:38 +0000 | [diff] [blame] | 1 | .\" $OpenBSD: ssh-keygen.1,v 1.32 2001/02/22 08:03:51 deraadt Exp $ |
Ben Lindstrom | 36579d3 | 2001-01-29 07:39:26 +0000 | [diff] [blame] | 2 | .\" |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 3 | .\" -*- nroff -*- |
| 4 | .\" |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 5 | .\" Author: Tatu Ylonen <ylo@cs.hut.fi> |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 6 | .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 7 | .\" All rights reserved |
| 8 | .\" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 9 | .\" As far as I am concerned, the code I have written for this software |
| 10 | .\" can be used freely for any purpose. Any derived versions of this |
| 11 | .\" software must be clearly marked as such, and if the derived work is |
| 12 | .\" incompatible with the protocol description in the RFC file, it must be |
| 13 | .\" called by a name other than "ssh" or "Secure Shell". |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 14 | .\" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 15 | .\" |
| 16 | .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved. |
| 17 | .\" Copyright (c) 1999 Aaron Campbell. All rights reserved. |
| 18 | .\" Copyright (c) 1999 Theo de Raadt. All rights reserved. |
| 19 | .\" |
| 20 | .\" Redistribution and use in source and binary forms, with or without |
| 21 | .\" modification, are permitted provided that the following conditions |
| 22 | .\" are met: |
| 23 | .\" 1. Redistributions of source code must retain the above copyright |
| 24 | .\" notice, this list of conditions and the following disclaimer. |
| 25 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| 26 | .\" notice, this list of conditions and the following disclaimer in the |
| 27 | .\" documentation and/or other materials provided with the distribution. |
| 28 | .\" |
| 29 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 30 | .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 31 | .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 32 | .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 33 | .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 34 | .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 35 | .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 36 | .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 37 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 38 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 39 | .\" |
| 40 | .Dd September 25, 1999 |
| 41 | .Dt SSH-KEYGEN 1 |
| 42 | .Os |
| 43 | .Sh NAME |
| 44 | .Nm ssh-keygen |
| 45 | .Nd authentication key generation |
| 46 | .Sh SYNOPSIS |
| 47 | .Nm ssh-keygen |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 48 | .Op Fl q |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 49 | .Op Fl b Ar bits |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 50 | .Op Fl t Ar type |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 51 | .Op Fl N Ar new_passphrase |
| 52 | .Op Fl C Ar comment |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 53 | .Op Fl f Ar output_keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 54 | .Nm ssh-keygen |
| 55 | .Fl p |
| 56 | .Op Fl P Ar old_passphrase |
| 57 | .Op Fl N Ar new_passphrase |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 58 | .Op Fl f Ar keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 59 | .Nm ssh-keygen |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 60 | .Fl x |
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 |
| 63 | .Fl X |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 64 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 65 | .Nm ssh-keygen |
| 66 | .Fl y |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 67 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 68 | .Nm ssh-keygen |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 69 | .Fl c |
| 70 | .Op Fl P Ar passphrase |
| 71 | .Op Fl C Ar comment |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 72 | .Op Fl f Ar keyfile |
| 73 | .Nm ssh-keygen |
| 74 | .Fl l |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 75 | .Op Fl f Ar input_keyfile |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 76 | .Sh DESCRIPTION |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 77 | .Nm |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 78 | generates and manages authentication keys for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 79 | .Xr ssh 1 . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 80 | .Nm |
| 81 | defaults to generating an RSA key for use by protocols 1.3 and 1.5; |
| 82 | specifying the |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 83 | .Fl t |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 84 | option allows you to create a key for use by protocol 2.0. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 85 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 86 | Normally each user wishing to use SSH |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 87 | with RSA or DSA authentication runs this once to create the authentication |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 88 | key in |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 89 | .Pa $HOME/.ssh/identity |
| 90 | or |
| 91 | .Pa $HOME/.ssh/id_dsa . |
| 92 | Additionally, the system administrator may use this to generate host keys, |
| 93 | as seen in |
| 94 | .Pa /etc/rc . |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 95 | .Pp |
| 96 | 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] | 97 | to store the private key. |
| 98 | 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] | 99 | .Dq .pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 100 | appended. |
| 101 | The program also asks for a passphrase. |
| 102 | The passphrase may be empty to indicate no passphrase |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 103 | (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] | 104 | arbitrary length. |
| 105 | Good passphrases are 10-30 characters long and are |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 106 | not simple sentences or otherwise easily guessable (English |
| 107 | prose has only 1-2 bits of entropy per word, and provides very bad |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 108 | passphrases). |
| 109 | The passphrase can be changed later by using the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 110 | .Fl p |
| 111 | option. |
| 112 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 113 | There is no way to recover a lost passphrase. |
| 114 | If the passphrase is |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 115 | lost or forgotten, you will have to generate a new key and copy the |
| 116 | corresponding public key to other machines. |
| 117 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 118 | For RSA, 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] | 119 | convenience to the user to help identify the key. |
| 120 | The comment can tell what the key is for, or whatever is useful. |
| 121 | The comment is initialized to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 122 | .Dq user@host |
| 123 | when the key is created, but can be changed using the |
| 124 | .Fl c |
| 125 | option. |
| 126 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 127 | After a key is generated, instructions below detail where the keys |
| 128 | should be placed to be activated. |
| 129 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 130 | The options are as follows: |
| 131 | .Bl -tag -width Ds |
| 132 | .It Fl b Ar bits |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 133 | Specifies the number of bits in the key to create. |
| 134 | Minimum is 512 bits. |
| 135 | Generally 1024 bits is considered sufficient, and key sizes |
| 136 | above that no longer improve security but make things slower. |
| 137 | The default is 1024 bits. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 138 | .It Fl c |
| 139 | Requests changing the comment in the private and public key files. |
| 140 | The program will prompt for the file containing the private keys, for |
| 141 | passphrase if the key has one, and for the new comment. |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 142 | .It Fl f |
| 143 | Specifies the filename of the key file. |
| 144 | .It Fl l |
| 145 | Show fingerprint of specified private or public key file. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 146 | .It Fl p |
| 147 | Requests changing the passphrase of a private key file instead of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 148 | creating a new private key. |
| 149 | The program will prompt for the file |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 150 | containing the private key, for the old passphrase, and twice for the |
| 151 | new passphrase. |
| 152 | .It Fl q |
| 153 | Silence |
| 154 | .Nm ssh-keygen . |
| 155 | Used by |
| 156 | .Pa /etc/rc |
| 157 | when creating a new key. |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 158 | .It Fl t Ar type |
| 159 | Specifies the type of the key to create. |
| 160 | The possible values are |
| 161 | .Dq rsa1 |
| 162 | for protocol version 1 and |
| 163 | .Dq rsa |
| 164 | or |
| 165 | .Dq dsa |
| 166 | for protocol version 2. |
| 167 | The default is |
Ben Lindstrom | b7c9232 | 2001-03-05 05:10:52 +0000 | [diff] [blame] | 168 | .Dq rsa1 . |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 169 | .It Fl C Ar comment |
| 170 | Provides the new comment. |
| 171 | .It Fl N Ar new_passphrase |
| 172 | Provides the new passphrase. |
| 173 | .It Fl P Ar passphrase |
| 174 | Provides the (old) passphrase. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 175 | .It Fl x |
| 176 | This option will read a private |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 177 | OpenSSH DSA format file and print a SSH2-compatible public key to stdout. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 178 | .It Fl X |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 179 | This option will read a unencrypted |
| 180 | SSH2-compatible private (or public) key file and |
| 181 | print an OpenSSH compatible private (or public) key to stdout. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 182 | .It Fl y |
| 183 | This option will read a private |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 184 | OpenSSH format file and print an OpenSSH public key to stdout. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 185 | .El |
| 186 | .Sh FILES |
| 187 | .Bl -tag -width Ds |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 188 | .It Pa $HOME/.ssh/identity |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 189 | Contains the RSA authentication identity of the user. |
| 190 | This file should not be readable by anyone but the user. |
| 191 | It is possible to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 192 | specify a passphrase when generating the key; that passphrase will be |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 193 | used to encrypt the private part of this file using 3DES. |
| 194 | This file is not automatically accessed by |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 195 | .Nm |
| 196 | but it is offered as the default file for the private key. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 197 | .Xr sshd 8 |
| 198 | will read this file when a login attempt is made. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 199 | .It Pa $HOME/.ssh/identity.pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 200 | Contains the public key for authentication. |
| 201 | The contents of this file should be added to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 202 | .Pa $HOME/.ssh/authorized_keys |
| 203 | on all machines |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 204 | where you wish to log in using RSA authentication. |
| 205 | There is no need to keep the contents of this file secret. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 206 | .It Pa $HOME/.ssh/id_dsa |
| 207 | Contains the DSA authentication identity of the user. |
| 208 | This file should not be readable by anyone but the user. |
| 209 | It is possible to |
| 210 | specify a passphrase when generating the key; that passphrase will be |
| 211 | used to encrypt the private part of this file using 3DES. |
| 212 | This file is not automatically accessed by |
| 213 | .Nm |
| 214 | but it is offered as the default file for the private key. |
| 215 | .Xr sshd 8 |
| 216 | will read this file when a login attempt is made. |
| 217 | .It Pa $HOME/.ssh/id_dsa.pub |
| 218 | Contains the public key for authentication. |
| 219 | The contents of this file should be added to |
| 220 | .Pa $HOME/.ssh/authorized_keys2 |
| 221 | on all machines |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 222 | where you wish to log in using public key authentication. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 223 | There is no need to keep the contents of this file secret. |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 224 | .El |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 225 | .Sh AUTHORS |
Ben Lindstrom | 035782e | 2001-01-29 08:34:16 +0000 | [diff] [blame] | 226 | OpenSSH is a derivative of the original and free |
| 227 | ssh 1.2.12 release by Tatu Ylonen. |
| 228 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, |
| 229 | Theo de Raadt and Dug Song |
| 230 | removed many bugs, re-added newer features and |
| 231 | created OpenSSH. |
| 232 | Markus Friedl contributed the support for SSH |
| 233 | protocol versions 1.5 and 2.0. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 234 | .Sh SEE ALSO |
| 235 | .Xr ssh 1 , |
| 236 | .Xr ssh-add 1 , |
Damien Miller | 2e8b1c8 | 1999-11-15 23:33:56 +1100 | [diff] [blame] | 237 | .Xr ssh-agent 1 , |
Ben Lindstrom | 77788dc | 2001-02-10 23:10:33 +0000 | [diff] [blame] | 238 | .Xr sshd 8 |