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b587c165 | 1 | .\" $OpenBSD: ssh-keygen.1,v 1.40 2001/04/23 21:57:07 markus Exp $ |
23c2a7a5 | 2 | .\" |
bf740959 | 3 | .\" -*- nroff -*- |
4 | .\" | |
bf740959 | 5 | .\" Author: Tatu Ylonen <ylo@cs.hut.fi> |
bf740959 | 6 | .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
7 | .\" All rights reserved | |
8 | .\" | |
bcbf86ec | 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". | |
14 | .\" | |
15 | .\" | |
f3c7c613 | 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. | |
bcbf86ec | 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. | |
bf740959 | 28 | .\" |
bcbf86ec | 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. | |
bf740959 | 39 | .\" |
40 | .Dd September 25, 1999 | |
41 | .Dt SSH-KEYGEN 1 | |
42 | .Os | |
43 | .Sh NAME | |
44 | .Nm ssh-keygen | |
5deceabb | 45 | .Nd authentication key generation, management and conversion |
bf740959 | 46 | .Sh SYNOPSIS |
47 | .Nm ssh-keygen | |
fa08c86b | 48 | .Op Fl q |
bf740959 | 49 | .Op Fl b Ar bits |
fa08c86b | 50 | .Op Fl t Ar type |
bf740959 | 51 | .Op Fl N Ar new_passphrase |
52 | .Op Fl C Ar comment | |
7cd3766c | 53 | .Op Fl f Ar output_keyfile |
bf740959 | 54 | .Nm ssh-keygen |
55 | .Fl p | |
56 | .Op Fl P Ar old_passphrase | |
57 | .Op Fl N Ar new_passphrase | |
f095fcc7 | 58 | .Op Fl f Ar keyfile |
bf740959 | 59 | .Nm ssh-keygen |
5deceabb | 60 | .Fl i |
7cd3766c | 61 | .Op Fl f Ar input_keyfile |
1d1ffb87 | 62 | .Nm ssh-keygen |
5deceabb | 63 | .Fl e |
7cd3766c | 64 | .Op Fl f Ar input_keyfile |
1d1ffb87 | 65 | .Nm ssh-keygen |
66 | .Fl y | |
7cd3766c | 67 | .Op Fl f Ar input_keyfile |
1d1ffb87 | 68 | .Nm ssh-keygen |
bf740959 | 69 | .Fl c |
70 | .Op Fl P Ar passphrase | |
71 | .Op Fl C Ar comment | |
f095fcc7 | 72 | .Op Fl f Ar keyfile |
73 | .Nm ssh-keygen | |
74 | .Fl l | |
aaf45d87 | 75 | .Op Fl f Ar input_keyfile |
76 | .Nm ssh-keygen | |
77 | .Fl B | |
7cd3766c | 78 | .Op Fl f Ar input_keyfile |
f54651ce | 79 | .Sh DESCRIPTION |
bf740959 | 80 | .Nm |
5deceabb | 81 | generates, manages and converts authentication keys for |
bf740959 | 82 | .Xr ssh 1 . |
1d1ffb87 | 83 | .Nm |
da89cf4d | 84 | defaults to generating a RSA1 key for use by SSH protocol version 1. |
1d1ffb87 | 85 | specifying the |
fa08c86b | 86 | .Fl t |
da89cf4d | 87 | option allows you to create a key for use by SSH protocol version 2. |
1d1ffb87 | 88 | .Pp |
bf740959 | 89 | Normally each user wishing to use SSH |
1d1ffb87 | 90 | with RSA or DSA authentication runs this once to create the authentication |
bf740959 | 91 | key in |
c0ecc314 | 92 | .Pa $HOME/.ssh/identity , |
93 | .Pa $HOME/.ssh/id_dsa | |
1d1ffb87 | 94 | or |
c0ecc314 | 95 | .Pa $HOME/.ssh/id_rsa . |
1d1ffb87 | 96 | Additionally, the system administrator may use this to generate host keys, |
97 | as seen in | |
98 | .Pa /etc/rc . | |
bf740959 | 99 | .Pp |
100 | Normally this program generates the key and asks for a file in which | |
4fe2af09 | 101 | to store the private key. |
102 | The public key is stored in a file with the same name but | |
bf740959 | 103 | .Dq .pub |
4fe2af09 | 104 | appended. |
105 | The program also asks for a passphrase. | |
106 | The passphrase may be empty to indicate no passphrase | |
b5c334cc | 107 | (host keys must have an empty passphrase), or it may be a string of |
4fe2af09 | 108 | arbitrary length. |
109 | Good passphrases are 10-30 characters long and are | |
bf740959 | 110 | not simple sentences or otherwise easily guessable (English |
111 | prose has only 1-2 bits of entropy per word, and provides very bad | |
4fe2af09 | 112 | passphrases). |
113 | The passphrase can be changed later by using the | |
bf740959 | 114 | .Fl p |
115 | option. | |
116 | .Pp | |
4fe2af09 | 117 | There is no way to recover a lost passphrase. |
118 | If the passphrase is | |
bf740959 | 119 | lost or forgotten, you will have to generate a new key and copy the |
120 | corresponding public key to other machines. | |
121 | .Pp | |
5deceabb | 122 | For RSA1 keys, |
123 | there is also a comment field in the key file that is only for | |
4fe2af09 | 124 | convenience to the user to help identify the key. |
125 | The comment can tell what the key is for, or whatever is useful. | |
126 | The comment is initialized to | |
bf740959 | 127 | .Dq user@host |
128 | when the key is created, but can be changed using the | |
129 | .Fl c | |
130 | option. | |
131 | .Pp | |
1d1ffb87 | 132 | After a key is generated, instructions below detail where the keys |
133 | should be placed to be activated. | |
134 | .Pp | |
bf740959 | 135 | The options are as follows: |
136 | .Bl -tag -width Ds | |
137 | .It Fl b Ar bits | |
4fe2af09 | 138 | Specifies the number of bits in the key to create. |
139 | Minimum is 512 bits. | |
140 | Generally 1024 bits is considered sufficient, and key sizes | |
141 | above that no longer improve security but make things slower. | |
142 | The default is 1024 bits. | |
bf740959 | 143 | .It Fl c |
144 | Requests changing the comment in the private and public key files. | |
145 | The program will prompt for the file containing the private keys, for | |
146 | passphrase if the key has one, and for the new comment. | |
5deceabb | 147 | .It Fl e |
b587c165 | 148 | This option will read a private or public OpenSSH key file and |
149 | print the key in a | |
5deceabb | 150 | .Sq SECSH Public Key File Format |
151 | to stdout. | |
152 | This option allows exporting keys for use by several commercial | |
153 | SSH implementations. | |
f095fcc7 | 154 | .It Fl f |
155 | Specifies the filename of the key file. | |
5deceabb | 156 | .It Fl i |
157 | This option will read an unencrypted private (or public) key file | |
158 | in SSH2-compatible format and print an OpenSSH compatible private | |
159 | (or public) key to stdout. | |
160 | .Nm | |
bcaa828e | 161 | also reads the |
5deceabb | 162 | .Sq SECSH Public Key File Format . |
163 | This option allows importing keys from several commercial | |
164 | SSH implementations. | |
f095fcc7 | 165 | .It Fl l |
166 | Show fingerprint of specified private or public key file. | |
bf740959 | 167 | .It Fl p |
168 | Requests changing the passphrase of a private key file instead of | |
4fe2af09 | 169 | creating a new private key. |
170 | The program will prompt for the file | |
bf740959 | 171 | containing the private key, for the old passphrase, and twice for the |
172 | new passphrase. | |
173 | .It Fl q | |
174 | Silence | |
175 | .Nm ssh-keygen . | |
176 | Used by | |
177 | .Pa /etc/rc | |
178 | when creating a new key. | |
5deceabb | 179 | .It Fl y |
180 | This option will read a private | |
181 | OpenSSH format file and print an OpenSSH public key to stdout. | |
fa08c86b | 182 | .It Fl t Ar type |
183 | Specifies the type of the key to create. | |
184 | The possible values are | |
185 | .Dq rsa1 | |
186 | for protocol version 1 and | |
187 | .Dq rsa | |
188 | or | |
189 | .Dq dsa | |
190 | for protocol version 2. | |
191 | The default is | |
ed2166d8 | 192 | .Dq rsa1 . |
aaf45d87 | 193 | .It Fl B |
194 | Show the bubblebabble digest of specified private or public key file. | |
bf740959 | 195 | .It Fl C Ar comment |
196 | Provides the new comment. | |
197 | .It Fl N Ar new_passphrase | |
198 | Provides the new passphrase. | |
199 | .It Fl P Ar passphrase | |
200 | Provides the (old) passphrase. | |
201 | .El | |
202 | .Sh FILES | |
203 | .Bl -tag -width Ds | |
bf740959 | 204 | .It Pa $HOME/.ssh/identity |
c0ecc314 | 205 | Contains the protocol version 1 RSA authentication identity of the user. |
4fe2af09 | 206 | This file should not be readable by anyone but the user. |
207 | It is possible to | |
bf740959 | 208 | specify a passphrase when generating the key; that passphrase will be |
4fe2af09 | 209 | used to encrypt the private part of this file using 3DES. |
210 | This file is not automatically accessed by | |
bf740959 | 211 | .Nm |
212 | but it is offered as the default file for the private key. | |
1d1ffb87 | 213 | .Xr sshd 8 |
214 | will read this file when a login attempt is made. | |
bf740959 | 215 | .It Pa $HOME/.ssh/identity.pub |
c0ecc314 | 216 | Contains the protocol version 1 RSA public key for authentication. |
4fe2af09 | 217 | The contents of this file should be added to |
bf740959 | 218 | .Pa $HOME/.ssh/authorized_keys |
219 | on all machines | |
4fe2af09 | 220 | where you wish to log in using RSA authentication. |
221 | There is no need to keep the contents of this file secret. | |
1d1ffb87 | 222 | .It Pa $HOME/.ssh/id_dsa |
c0ecc314 | 223 | Contains the protocol version 2 DSA authentication identity of the user. |
1d1ffb87 | 224 | This file should not be readable by anyone but the user. |
225 | It is possible to | |
226 | specify a passphrase when generating the key; that passphrase will be | |
227 | used to encrypt the private part of this file using 3DES. | |
228 | This file is not automatically accessed by | |
229 | .Nm | |
230 | but it is offered as the default file for the private key. | |
231 | .Xr sshd 8 | |
232 | will read this file when a login attempt is made. | |
233 | .It Pa $HOME/.ssh/id_dsa.pub | |
c0ecc314 | 234 | Contains the protocol version 2 DSA public key for authentication. |
235 | The contents of this file should be added to | |
236 | .Pa $HOME/.ssh/authorized_keys2 | |
237 | on all machines | |
238 | where you wish to log in using public key authentication. | |
239 | There is no need to keep the contents of this file secret. | |
240 | .It Pa $HOME/.ssh/id_rsa | |
241 | Contains the protocol version 2 RSA authentication identity of the user. | |
242 | This file should not be readable by anyone but the user. | |
243 | It is possible to | |
244 | specify a passphrase when generating the key; that passphrase will be | |
245 | used to encrypt the private part of this file using 3DES. | |
246 | This file is not automatically accessed by | |
247 | .Nm | |
248 | but it is offered as the default file for the private key. | |
249 | .Xr sshd 8 | |
250 | will read this file when a login attempt is made. | |
251 | .It Pa $HOME/.ssh/id_rsa.pub | |
252 | Contains the protocol version 2 RSA public key for authentication. | |
1d1ffb87 | 253 | The contents of this file should be added to |
254 | .Pa $HOME/.ssh/authorized_keys2 | |
255 | on all machines | |
fa08c86b | 256 | where you wish to log in using public key authentication. |
1d1ffb87 | 257 | There is no need to keep the contents of this file secret. |
089fbbd2 | 258 | .El |
fa08c86b | 259 | .Sh AUTHORS |
5fb622e4 | 260 | OpenSSH is a derivative of the original and free |
261 | ssh 1.2.12 release by Tatu Ylonen. | |
262 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
263 | Theo de Raadt and Dug Song | |
264 | removed many bugs, re-added newer features and | |
265 | created OpenSSH. | |
266 | Markus Friedl contributed the support for SSH | |
267 | protocol versions 1.5 and 2.0. | |
bf740959 | 268 | .Sh SEE ALSO |
269 | .Xr ssh 1 , | |
270 | .Xr ssh-add 1 , | |
0c372277 | 271 | .Xr ssh-agent 1 , |
a5ef76f1 | 272 | .Xr sshd 8 |
5deceabb | 273 | .Rs |
274 | .%A J. Galbraith | |
275 | .%A R. Thayer | |
276 | .%T "SECSH Public Key File Format" | |
277 | .%N draft-ietf-secsh-publickeyfile-01.txt | |
278 | .%D March 2001 | |
279 | .%O work in progress material | |
280 | .Re |