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91789042 | 1 | .\" $OpenBSD: ssh-keygen.1,v 1.49 2001/09/05 06:23:07 deraadt 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 |
f0d6bdcf | 79 | .Nm ssh-keygen |
80 | .Fl D Ar reader | |
81 | .Nm ssh-keygen | |
82 | .Fl U Ar reader | |
83 | .Op Fl f Ar input_keyfile | |
f54651ce | 84 | .Sh DESCRIPTION |
bf740959 | 85 | .Nm |
5deceabb | 86 | generates, manages and converts authentication keys for |
bf740959 | 87 | .Xr ssh 1 . |
1d1ffb87 | 88 | .Nm |
da89cf4d | 89 | defaults to generating a RSA1 key for use by SSH protocol version 1. |
7fd9477e | 90 | Specifying the |
fa08c86b | 91 | .Fl t |
91789042 | 92 | option instead creates a key for use by SSH protocol version 2. |
1d1ffb87 | 93 | .Pp |
bf740959 | 94 | Normally each user wishing to use SSH |
1d1ffb87 | 95 | with RSA or DSA authentication runs this once to create the authentication |
bf740959 | 96 | key in |
c0ecc314 | 97 | .Pa $HOME/.ssh/identity , |
98 | .Pa $HOME/.ssh/id_dsa | |
1d1ffb87 | 99 | or |
c0ecc314 | 100 | .Pa $HOME/.ssh/id_rsa . |
1d1ffb87 | 101 | Additionally, the system administrator may use this to generate host keys, |
102 | as seen in | |
103 | .Pa /etc/rc . | |
bf740959 | 104 | .Pp |
105 | Normally this program generates the key and asks for a file in which | |
4fe2af09 | 106 | to store the private key. |
107 | The public key is stored in a file with the same name but | |
bf740959 | 108 | .Dq .pub |
4fe2af09 | 109 | appended. |
110 | The program also asks for a passphrase. | |
111 | The passphrase may be empty to indicate no passphrase | |
b5c334cc | 112 | (host keys must have an empty passphrase), or it may be a string of |
4fe2af09 | 113 | arbitrary length. |
114 | Good passphrases are 10-30 characters long and are | |
bf740959 | 115 | not simple sentences or otherwise easily guessable (English |
e5b71e99 | 116 | prose has only 1-2 bits of entropy per character, and provides very bad |
4fe2af09 | 117 | passphrases). |
118 | The passphrase can be changed later by using the | |
bf740959 | 119 | .Fl p |
120 | option. | |
121 | .Pp | |
4fe2af09 | 122 | There is no way to recover a lost passphrase. |
123 | If the passphrase is | |
91789042 | 124 | lost or forgotten, a new key must be generated and copied to the |
bf740959 | 125 | corresponding public key to other machines. |
126 | .Pp | |
5deceabb | 127 | For RSA1 keys, |
128 | there is also a comment field in the key file that is only for | |
4fe2af09 | 129 | convenience to the user to help identify the key. |
130 | The comment can tell what the key is for, or whatever is useful. | |
131 | The comment is initialized to | |
bf740959 | 132 | .Dq user@host |
133 | when the key is created, but can be changed using the | |
134 | .Fl c | |
135 | option. | |
136 | .Pp | |
1d1ffb87 | 137 | After a key is generated, instructions below detail where the keys |
138 | should be placed to be activated. | |
139 | .Pp | |
bf740959 | 140 | The options are as follows: |
141 | .Bl -tag -width Ds | |
142 | .It Fl b Ar bits | |
4fe2af09 | 143 | Specifies the number of bits in the key to create. |
144 | Minimum is 512 bits. | |
145 | Generally 1024 bits is considered sufficient, and key sizes | |
146 | above that no longer improve security but make things slower. | |
147 | The default is 1024 bits. | |
bf740959 | 148 | .It Fl c |
149 | Requests changing the comment in the private and public key files. | |
150 | The program will prompt for the file containing the private keys, for | |
cf7ff074 | 151 | the passphrase if the key has one, and for the new comment. |
5deceabb | 152 | .It Fl e |
b587c165 | 153 | This option will read a private or public OpenSSH key file and |
154 | print the key in a | |
5deceabb | 155 | .Sq SECSH Public Key File Format |
156 | to stdout. | |
157 | This option allows exporting keys for use by several commercial | |
158 | SSH implementations. | |
f0d6bdcf | 159 | .It Fl f Ar filename |
f095fcc7 | 160 | Specifies the filename of the key file. |
5deceabb | 161 | .It Fl i |
162 | This option will read an unencrypted private (or public) key file | |
163 | in SSH2-compatible format and print an OpenSSH compatible private | |
164 | (or public) key to stdout. | |
165 | .Nm | |
bcaa828e | 166 | also reads the |
5deceabb | 167 | .Sq SECSH Public Key File Format . |
168 | This option allows importing keys from several commercial | |
169 | SSH implementations. | |
f095fcc7 | 170 | .It Fl l |
171 | Show fingerprint of specified private or public key file. | |
bf740959 | 172 | .It Fl p |
173 | Requests changing the passphrase of a private key file instead of | |
4fe2af09 | 174 | creating a new private key. |
175 | The program will prompt for the file | |
bf740959 | 176 | containing the private key, for the old passphrase, and twice for the |
177 | new passphrase. | |
178 | .It Fl q | |
179 | Silence | |
180 | .Nm ssh-keygen . | |
181 | Used by | |
182 | .Pa /etc/rc | |
183 | when creating a new key. | |
5deceabb | 184 | .It Fl y |
185 | This option will read a private | |
186 | OpenSSH format file and print an OpenSSH public key to stdout. | |
fa08c86b | 187 | .It Fl t Ar type |
188 | Specifies the type of the key to create. | |
189 | The possible values are | |
190 | .Dq rsa1 | |
191 | for protocol version 1 and | |
192 | .Dq rsa | |
193 | or | |
194 | .Dq dsa | |
195 | for protocol version 2. | |
196 | The default is | |
ed2166d8 | 197 | .Dq rsa1 . |
aaf45d87 | 198 | .It Fl B |
199 | Show the bubblebabble digest of specified private or public key file. | |
bf740959 | 200 | .It Fl C Ar comment |
201 | Provides the new comment. | |
f0d6bdcf | 202 | .It Fl D Ar reader |
203 | Download the RSA public key stored in the smartcard in | |
204 | .Ar reader . | |
bf740959 | 205 | .It Fl N Ar new_passphrase |
206 | Provides the new passphrase. | |
207 | .It Fl P Ar passphrase | |
208 | Provides the (old) passphrase. | |
f0d6bdcf | 209 | .It Fl U Ar reader |
210 | Upload an existing RSA private key into the smartcard in | |
211 | .Ar reader . | |
bf740959 | 212 | .El |
213 | .Sh FILES | |
214 | .Bl -tag -width Ds | |
bf740959 | 215 | .It Pa $HOME/.ssh/identity |
c0ecc314 | 216 | Contains the protocol version 1 RSA authentication identity of the user. |
4fe2af09 | 217 | This file should not be readable by anyone but the user. |
218 | It is possible to | |
bf740959 | 219 | specify a passphrase when generating the key; that passphrase will be |
4fe2af09 | 220 | used to encrypt the private part of this file using 3DES. |
221 | This file is not automatically accessed by | |
bf740959 | 222 | .Nm |
223 | but it is offered as the default file for the private key. | |
8a497b11 | 224 | .Xr ssh 1 |
1d1ffb87 | 225 | will read this file when a login attempt is made. |
bf740959 | 226 | .It Pa $HOME/.ssh/identity.pub |
c0ecc314 | 227 | Contains the protocol version 1 RSA public key for authentication. |
4fe2af09 | 228 | The contents of this file should be added to |
bf740959 | 229 | .Pa $HOME/.ssh/authorized_keys |
230 | on all machines | |
91789042 | 231 | where the user wishes to log in using RSA authentication. |
4fe2af09 | 232 | There is no need to keep the contents of this file secret. |
1d1ffb87 | 233 | .It Pa $HOME/.ssh/id_dsa |
c0ecc314 | 234 | Contains the protocol version 2 DSA authentication identity of the user. |
1d1ffb87 | 235 | This file should not be readable by anyone but the user. |
236 | It is possible to | |
237 | specify a passphrase when generating the key; that passphrase will be | |
238 | used to encrypt the private part of this file using 3DES. | |
239 | This file is not automatically accessed by | |
240 | .Nm | |
241 | but it is offered as the default file for the private key. | |
8a497b11 | 242 | .Xr ssh 1 |
1d1ffb87 | 243 | will read this file when a login attempt is made. |
244 | .It Pa $HOME/.ssh/id_dsa.pub | |
c0ecc314 | 245 | Contains the protocol version 2 DSA public key for authentication. |
246 | The contents of this file should be added to | |
96a7b0cc | 247 | .Pa $HOME/.ssh/authorized_keys |
c0ecc314 | 248 | on all machines |
91789042 | 249 | where the user wishes to log in using public key authentication. |
c0ecc314 | 250 | There is no need to keep the contents of this file secret. |
251 | .It Pa $HOME/.ssh/id_rsa | |
252 | Contains the protocol version 2 RSA authentication identity of the user. | |
253 | This file should not be readable by anyone but the user. | |
254 | It is possible to | |
255 | specify a passphrase when generating the key; that passphrase will be | |
256 | used to encrypt the private part of this file using 3DES. | |
257 | This file is not automatically accessed by | |
258 | .Nm | |
259 | but it is offered as the default file for the private key. | |
8a497b11 | 260 | .Xr ssh 1 |
c0ecc314 | 261 | will read this file when a login attempt is made. |
262 | .It Pa $HOME/.ssh/id_rsa.pub | |
263 | Contains the protocol version 2 RSA public key for authentication. | |
1d1ffb87 | 264 | The contents of this file should be added to |
96a7b0cc | 265 | .Pa $HOME/.ssh/authorized_keys |
1d1ffb87 | 266 | on all machines |
91789042 | 267 | where the user wishes to log in using public key authentication. |
1d1ffb87 | 268 | There is no need to keep the contents of this file secret. |
089fbbd2 | 269 | .El |
fa08c86b | 270 | .Sh AUTHORS |
5fb622e4 | 271 | OpenSSH is a derivative of the original and free |
272 | ssh 1.2.12 release by Tatu Ylonen. | |
273 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
274 | Theo de Raadt and Dug Song | |
275 | removed many bugs, re-added newer features and | |
276 | created OpenSSH. | |
277 | Markus Friedl contributed the support for SSH | |
278 | protocol versions 1.5 and 2.0. | |
bf740959 | 279 | .Sh SEE ALSO |
280 | .Xr ssh 1 , | |
281 | .Xr ssh-add 1 , | |
0c372277 | 282 | .Xr ssh-agent 1 , |
a5ef76f1 | 283 | .Xr sshd 8 |
5deceabb | 284 | .Rs |
7b518233 | 285 | .%A J. Galbraith |
286 | .%A R. Thayer | |
5deceabb | 287 | .%T "SECSH Public Key File Format" |
288 | .%N draft-ietf-secsh-publickeyfile-01.txt | |
289 | .%D March 2001 | |
290 | .%O work in progress material | |
291 | .Re |