Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.34
1.34 ! jakob 1: .\" $OpenBSD: ssh-keygen.1,v 1.33 2001/03/02 18:54:31 deraadt Exp $
1.29 niklas 2: .\"
1.1 deraadt 3: .\" -*- nroff -*-
4: .\"
5: .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
6: .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7: .\" All rights reserved
8: .\"
1.22 deraadt 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: .\"
1.33 deraadt 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.
1.22 deraadt 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.
1.1 deraadt 28: .\"
1.22 deraadt 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.
1.1 deraadt 39: .\"
1.2 deraadt 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
1.25 markus 48: .Op Fl q
1.2 deraadt 49: .Op Fl b Ar bits
1.25 markus 50: .Op Fl t Ar type
1.2 deraadt 51: .Op Fl N Ar new_passphrase
52: .Op Fl C Ar comment
1.20 markus 53: .Op Fl f Ar output_keyfile
1.2 deraadt 54: .Nm ssh-keygen
55: .Fl p
56: .Op Fl P Ar old_passphrase
57: .Op Fl N Ar new_passphrase
1.9 markus 58: .Op Fl f Ar keyfile
1.2 deraadt 59: .Nm ssh-keygen
1.16 deraadt 60: .Fl x
1.20 markus 61: .Op Fl f Ar input_keyfile
1.16 deraadt 62: .Nm ssh-keygen
63: .Fl X
1.20 markus 64: .Op Fl f Ar input_keyfile
1.16 deraadt 65: .Nm ssh-keygen
1.17 markus 66: .Fl y
1.20 markus 67: .Op Fl f Ar input_keyfile
1.17 markus 68: .Nm ssh-keygen
1.2 deraadt 69: .Fl c
70: .Op Fl P Ar passphrase
71: .Op Fl C Ar comment
1.9 markus 72: .Op Fl f Ar keyfile
73: .Nm ssh-keygen
74: .Fl l
1.34 ! jakob 75: .Op Fl v
1.20 markus 76: .Op Fl f Ar input_keyfile
1.13 aaron 77: .Sh DESCRIPTION
1.2 deraadt 78: .Nm
1.13 aaron 79: generates and manages authentication keys for
1.2 deraadt 80: .Xr ssh 1 .
1.15 deraadt 81: .Nm
82: defaults to generating an RSA key for use by protocols 1.3 and 1.5;
83: specifying the
1.25 markus 84: .Fl t
1.26 markus 85: option allows you to create a key for use by protocol 2.0.
1.15 deraadt 86: .Pp
1.2 deraadt 87: Normally each user wishing to use SSH
1.15 deraadt 88: with RSA or DSA authentication runs this once to create the authentication
1.1 deraadt 89: key in
1.15 deraadt 90: .Pa $HOME/.ssh/identity
91: or
92: .Pa $HOME/.ssh/id_dsa .
93: Additionally, the system administrator may use this to generate host keys,
94: as seen in
95: .Pa /etc/rc .
1.2 deraadt 96: .Pp
1.1 deraadt 97: Normally this program generates the key and asks for a file in which
1.12 aaron 98: to store the private key.
99: The public key is stored in a file with the same name but
1.2 deraadt 100: .Dq .pub
1.12 aaron 101: appended.
102: The program also asks for a passphrase.
103: The passphrase may be empty to indicate no passphrase
1.26 markus 104: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 105: arbitrary length.
106: Good passphrases are 10-30 characters long and are
1.1 deraadt 107: not simple sentences or otherwise easily guessable (English
108: prose has only 1-2 bits of entropy per word, and provides very bad
1.12 aaron 109: passphrases).
110: The passphrase can be changed later by using the
1.2 deraadt 111: .Fl p
1.1 deraadt 112: option.
1.2 deraadt 113: .Pp
1.12 aaron 114: There is no way to recover a lost passphrase.
115: If the passphrase is
1.1 deraadt 116: lost or forgotten, you will have to generate a new key and copy the
117: corresponding public key to other machines.
1.2 deraadt 118: .Pp
1.15 deraadt 119: For RSA, there is also a comment field in the key file that is only for
1.12 aaron 120: convenience to the user to help identify the key.
121: The comment can tell what the key is for, or whatever is useful.
122: The comment is initialized to
1.2 deraadt 123: .Dq user@host
124: when the key is created, but can be changed using the
125: .Fl c
1.1 deraadt 126: option.
1.2 deraadt 127: .Pp
1.15 deraadt 128: After a key is generated, instructions below detail where the keys
129: should be placed to be activated.
130: .Pp
1.2 deraadt 131: The options are as follows:
132: .Bl -tag -width Ds
133: .It Fl b Ar bits
1.12 aaron 134: Specifies the number of bits in the key to create.
135: Minimum is 512 bits.
136: Generally 1024 bits is considered sufficient, and key sizes
137: above that no longer improve security but make things slower.
138: The default is 1024 bits.
1.2 deraadt 139: .It Fl c
1.1 deraadt 140: Requests changing the comment in the private and public key files.
141: The program will prompt for the file containing the private keys, for
142: passphrase if the key has one, and for the new comment.
1.9 markus 143: .It Fl f
144: Specifies the filename of the key file.
145: .It Fl l
146: Show fingerprint of specified private or public key file.
1.2 deraadt 147: .It Fl p
1.1 deraadt 148: Requests changing the passphrase of a private key file instead of
1.12 aaron 149: creating a new private key.
150: The program will prompt for the file
1.1 deraadt 151: containing the private key, for the old passphrase, and twice for the
152: new passphrase.
1.5 aaron 153: .It Fl q
154: Silence
155: .Nm ssh-keygen .
156: Used by
157: .Pa /etc/rc
158: when creating a new key.
1.25 markus 159: .It Fl t Ar type
160: Specifies the type of the key to create.
161: The possible values are
162: .Dq rsa1
163: for protocol version 1 and
164: .Dq rsa
165: or
166: .Dq dsa
167: for protocol version 2.
168: The default is
1.31 deraadt 169: .Dq rsa1 .
1.2 deraadt 170: .It Fl C Ar comment
1.1 deraadt 171: Provides the new comment.
1.2 deraadt 172: .It Fl N Ar new_passphrase
1.1 deraadt 173: Provides the new passphrase.
1.2 deraadt 174: .It Fl P Ar passphrase
1.1 deraadt 175: Provides the (old) passphrase.
1.34 ! jakob 176: .It Fl v
! 177: Print verbose information.
1.16 deraadt 178: .It Fl x
1.17 markus 179: This option will read a private
1.18 hugh 180: OpenSSH DSA format file and print a SSH2-compatible public key to stdout.
1.16 deraadt 181: .It Fl X
1.23 markus 182: This option will read a unencrypted
183: SSH2-compatible private (or public) key file and
184: print an OpenSSH compatible private (or public) key to stdout.
1.17 markus 185: .It Fl y
186: This option will read a private
1.25 markus 187: OpenSSH format file and print an OpenSSH public key to stdout.
1.2 deraadt 188: .El
189: .Sh FILES
190: .Bl -tag -width Ds
191: .It Pa $HOME/.ssh/identity
1.12 aaron 192: Contains the RSA authentication identity of the user.
193: This file should not be readable by anyone but the user.
194: It is possible to
1.1 deraadt 195: specify a passphrase when generating the key; that passphrase will be
1.12 aaron 196: used to encrypt the private part of this file using 3DES.
197: This file is not automatically accessed by
1.2 deraadt 198: .Nm
1.1 deraadt 199: but it is offered as the default file for the private key.
1.15 deraadt 200: .Xr sshd 8
201: will read this file when a login attempt is made.
1.2 deraadt 202: .It Pa $HOME/.ssh/identity.pub
1.12 aaron 203: Contains the public key for authentication.
204: The contents of this file should be added to
1.2 deraadt 205: .Pa $HOME/.ssh/authorized_keys
206: on all machines
1.12 aaron 207: where you wish to log in using RSA authentication.
1.15 deraadt 208: There is no need to keep the contents of this file secret.
209: .It Pa $HOME/.ssh/id_dsa
210: Contains the DSA authentication identity of the user.
211: This file should not be readable by anyone but the user.
212: It is possible to
213: specify a passphrase when generating the key; that passphrase will be
214: used to encrypt the private part of this file using 3DES.
215: This file is not automatically accessed by
216: .Nm
217: but it is offered as the default file for the private key.
218: .Xr sshd 8
219: will read this file when a login attempt is made.
220: .It Pa $HOME/.ssh/id_dsa.pub
221: Contains the public key for authentication.
222: The contents of this file should be added to
223: .Pa $HOME/.ssh/authorized_keys2
224: on all machines
1.25 markus 225: where you wish to log in using public key authentication.
1.12 aaron 226: There is no need to keep the contents of this file secret.
1.19 aaron 227: .El
1.24 aaron 228: .Sh AUTHORS
1.28 markus 229: OpenSSH is a derivative of the original and free
230: ssh 1.2.12 release by Tatu Ylonen.
231: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
232: Theo de Raadt and Dug Song
233: removed many bugs, re-added newer features and
234: created OpenSSH.
235: Markus Friedl contributed the support for SSH
236: protocol versions 1.5 and 2.0.
1.2 deraadt 237: .Sh SEE ALSO
238: .Xr ssh 1 ,
239: .Xr ssh-add 1 ,
1.8 ericj 240: .Xr ssh-agent 1 ,
1.30 itojun 241: .Xr sshd 8
![[BACK]](/icons/back.gif){kind=icon}
Return to ssh-keygen.1 CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh