Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 1 | .\" -*- nroff -*- |
| 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 | .\" |
| 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. |
| 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 | .\" |
| 38 | .Dd September 25, 1999 |
| 39 | .Dt SSH-KEYGEN 1 |
| 40 | .Os |
| 41 | .Sh NAME |
| 42 | .Nm ssh-keygen |
| 43 | .Nd authentication key generation |
| 44 | .Sh SYNOPSIS |
| 45 | .Nm ssh-keygen |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 46 | .Op Fl dq |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 47 | .Op Fl b Ar bits |
| 48 | .Op Fl N Ar new_passphrase |
| 49 | .Op Fl C Ar comment |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 50 | .Op Fl f Ar output_keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 51 | .Nm ssh-keygen |
| 52 | .Fl p |
| 53 | .Op Fl P Ar old_passphrase |
| 54 | .Op Fl N Ar new_passphrase |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 55 | .Op Fl f Ar keyfile |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 56 | .Nm ssh-keygen |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 57 | .Fl x |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 58 | .Op Fl f Ar input_keyfile |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 59 | .Nm ssh-keygen |
| 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 y |
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 |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 66 | .Fl c |
| 67 | .Op Fl P Ar passphrase |
| 68 | .Op Fl C Ar comment |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 69 | .Op Fl f Ar keyfile |
| 70 | .Nm ssh-keygen |
| 71 | .Fl l |
Damien Miller | 1a425f3 | 2000-09-02 10:08:09 +1100 | [diff] [blame] | 72 | .Op Fl f Ar input_keyfile |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 73 | .Nm ssh-keygen |
| 74 | .Fl R |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 75 | .Sh DESCRIPTION |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 76 | .Nm |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 77 | generates and manages authentication keys for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 78 | .Xr ssh 1 . |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 79 | .Nm |
| 80 | defaults to generating an RSA key for use by protocols 1.3 and 1.5; |
| 81 | specifying the |
| 82 | .Fl d |
| 83 | flag will create a DSA key instead for use by protocol 2.0. |
| 84 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 85 | Normally each user wishing to use SSH |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 86 | with RSA or DSA authentication runs this once to create the authentication |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 87 | key in |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 88 | .Pa $HOME/.ssh/identity |
| 89 | or |
| 90 | .Pa $HOME/.ssh/id_dsa . |
| 91 | Additionally, the system administrator may use this to generate host keys, |
| 92 | as seen in |
| 93 | .Pa /etc/rc . |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 94 | .Pp |
| 95 | 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] | 96 | to store the private key. |
| 97 | 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] | 98 | .Dq .pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 99 | appended. |
| 100 | The program also asks for a passphrase. |
| 101 | The passphrase may be empty to indicate no passphrase |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 102 | (host keys must have empty passphrase), or it may be a string of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 103 | arbitrary length. |
| 104 | Good passphrases are 10-30 characters long and are |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 105 | not simple sentences or otherwise easily guessable (English |
| 106 | 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] | 107 | passphrases). |
| 108 | The passphrase can be changed later by using the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 109 | .Fl p |
| 110 | option. |
| 111 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 112 | There is no way to recover a lost passphrase. |
| 113 | If the passphrase is |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 114 | lost or forgotten, you will have to generate a new key and copy the |
| 115 | corresponding public key to other machines. |
| 116 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 117 | 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] | 118 | convenience to the user to help identify the key. |
| 119 | The comment can tell what the key is for, or whatever is useful. |
| 120 | The comment is initialized to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 121 | .Dq user@host |
| 122 | when the key is created, but can be changed using the |
| 123 | .Fl c |
| 124 | option. |
| 125 | .Pp |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 126 | After a key is generated, instructions below detail where the keys |
| 127 | should be placed to be activated. |
| 128 | .Pp |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 129 | The options are as follows: |
| 130 | .Bl -tag -width Ds |
| 131 | .It Fl b Ar bits |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 132 | Specifies the number of bits in the key to create. |
| 133 | Minimum is 512 bits. |
| 134 | Generally 1024 bits is considered sufficient, and key sizes |
| 135 | above that no longer improve security but make things slower. |
| 136 | The default is 1024 bits. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 137 | .It Fl c |
| 138 | Requests changing the comment in the private and public key files. |
| 139 | The program will prompt for the file containing the private keys, for |
| 140 | passphrase if the key has one, and for the new comment. |
Damien Miller | 10f6f6b | 1999-11-17 17:29:08 +1100 | [diff] [blame] | 141 | .It Fl f |
| 142 | Specifies the filename of the key file. |
| 143 | .It Fl l |
| 144 | Show fingerprint of specified private or public key file. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 145 | .It Fl p |
| 146 | Requests changing the passphrase of a private key file instead of |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 147 | creating a new private key. |
| 148 | The program will prompt for the file |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 149 | containing the private key, for the old passphrase, and twice for the |
| 150 | new passphrase. |
| 151 | .It Fl q |
| 152 | Silence |
| 153 | .Nm ssh-keygen . |
| 154 | Used by |
| 155 | .Pa /etc/rc |
| 156 | when creating a new key. |
| 157 | .It Fl C Ar comment |
| 158 | Provides the new comment. |
| 159 | .It Fl N Ar new_passphrase |
| 160 | Provides the new passphrase. |
| 161 | .It Fl P Ar passphrase |
| 162 | Provides the (old) passphrase. |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 163 | .It Fl R |
| 164 | If RSA support is functional, immediately exits with code 0. If RSA |
| 165 | support is not functional, exits with code 1. This flag will be |
| 166 | removed once the RSA patent expires. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 167 | .It Fl x |
| 168 | This option will read a private |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 169 | 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] | 170 | .It Fl X |
| 171 | This option will read a |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 172 | SSH2-compatible public key file and print an OpenSSH DSA compatible public key to stdout. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 173 | .It Fl y |
| 174 | This option will read a private |
Damien Miller | 30c3d42 | 2000-05-09 11:02:59 +1000 | [diff] [blame] | 175 | OpenSSH DSA format file and print an OpenSSH DSA public key to stdout. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 176 | .El |
| 177 | .Sh FILES |
| 178 | .Bl -tag -width Ds |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 179 | .It Pa $HOME/.ssh/identity |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 180 | Contains the RSA authentication identity of the user. |
| 181 | This file should not be readable by anyone but the user. |
| 182 | It is possible to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 183 | specify a passphrase when generating the key; that passphrase will be |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 184 | used to encrypt the private part of this file using 3DES. |
| 185 | This file is not automatically accessed by |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 186 | .Nm |
| 187 | but it is offered as the default file for the private key. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 188 | .Xr sshd 8 |
| 189 | will read this file when a login attempt is made. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 190 | .It Pa $HOME/.ssh/identity.pub |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 191 | Contains the public key for authentication. |
| 192 | The contents of this file should be added to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 193 | .Pa $HOME/.ssh/authorized_keys |
| 194 | on all machines |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 195 | where you wish to log in using RSA authentication. |
| 196 | There is no need to keep the contents of this file secret. |
Damien Miller | e247cc4 | 2000-05-07 12:03:14 +1000 | [diff] [blame] | 197 | .It Pa $HOME/.ssh/id_dsa |
| 198 | Contains the DSA authentication identity of the user. |
| 199 | This file should not be readable by anyone but the user. |
| 200 | It is possible to |
| 201 | specify a passphrase when generating the key; that passphrase will be |
| 202 | used to encrypt the private part of this file using 3DES. |
| 203 | This file is not automatically accessed by |
| 204 | .Nm |
| 205 | but it is offered as the default file for the private key. |
| 206 | .Xr sshd 8 |
| 207 | will read this file when a login attempt is made. |
| 208 | .It Pa $HOME/.ssh/id_dsa.pub |
| 209 | Contains the public key for authentication. |
| 210 | The contents of this file should be added to |
| 211 | .Pa $HOME/.ssh/authorized_keys2 |
| 212 | on all machines |
| 213 | where you wish to log in using DSA authentication. |
| 214 | There is no need to keep the contents of this file secret. |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 215 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 216 | .Sh AUTHOR |
| 217 | Tatu Ylonen <ylo@cs.hut.fi> |
| 218 | .Pp |
| 219 | OpenSSH |
| 220 | is a derivative of the original (free) ssh 1.2.12 release, but with bugs |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 221 | removed and newer features re-added. |
| 222 | Rapidly after the 1.2.12 release, |
| 223 | newer versions bore successively more restrictive licenses. |
| 224 | This version of OpenSSH |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 225 | .Bl -bullet |
| 226 | .It |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame^] | 227 | has all components of a restrictive nature (i.e., patents, see |
| 228 | .Xr crypto 3 ) |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 229 | directly removed from the source code; any licensed or patented components |
| 230 | are chosen from |
| 231 | external libraries. |
| 232 | .It |
| 233 | has been updated to support ssh protocol 1.5. |
| 234 | .It |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 235 | contains added support for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 236 | .Xr kerberos 8 |
| 237 | authentication and ticket passing. |
| 238 | .It |
| 239 | supports one-time password authentication with |
| 240 | .Xr skey 1 . |
| 241 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 242 | .Sh SEE ALSO |
| 243 | .Xr ssh 1 , |
| 244 | .Xr ssh-add 1 , |
Damien Miller | 2e8b1c8 | 1999-11-15 23:33:56 +1100 | [diff] [blame] | 245 | .Xr ssh-agent 1 , |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 246 | .Xr sshd 8 , |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame^] | 247 | .Xr crypto 3 |