Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.56
1.56 ! jmc 1: .\" $OpenBSD: ssh-keygen.1,v 1.55 2002/11/26 02:35:30 stevesk 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
1.37 markus 45: .Nd authentication key generation, management and conversion
1.2 deraadt 46: .Sh SYNOPSIS
47: .Nm ssh-keygen
1.56 ! jmc 48: .Bk -words
1.25 markus 49: .Op Fl q
1.2 deraadt 50: .Op Fl b Ar bits
1.53 stevesk 51: .Fl t Ar type
1.2 deraadt 52: .Op Fl N Ar new_passphrase
53: .Op Fl C Ar comment
1.20 markus 54: .Op Fl f Ar output_keyfile
1.56 ! jmc 55: .Ek
1.2 deraadt 56: .Nm ssh-keygen
57: .Fl p
58: .Op Fl P Ar old_passphrase
59: .Op Fl N Ar new_passphrase
1.9 markus 60: .Op Fl f Ar keyfile
1.2 deraadt 61: .Nm ssh-keygen
1.37 markus 62: .Fl i
1.20 markus 63: .Op Fl f Ar input_keyfile
1.16 deraadt 64: .Nm ssh-keygen
1.37 markus 65: .Fl e
1.20 markus 66: .Op Fl f Ar input_keyfile
1.16 deraadt 67: .Nm ssh-keygen
1.17 markus 68: .Fl y
1.20 markus 69: .Op Fl f Ar input_keyfile
1.17 markus 70: .Nm ssh-keygen
1.2 deraadt 71: .Fl c
72: .Op Fl P Ar passphrase
73: .Op Fl C Ar comment
1.9 markus 74: .Op Fl f Ar keyfile
75: .Nm ssh-keygen
76: .Fl l
1.35 markus 77: .Op Fl f Ar input_keyfile
78: .Nm ssh-keygen
79: .Fl B
1.20 markus 80: .Op Fl f Ar input_keyfile
1.48 jakob 81: .Nm ssh-keygen
82: .Fl D Ar reader
83: .Nm ssh-keygen
84: .Fl U Ar reader
85: .Op Fl f Ar input_keyfile
1.13 aaron 86: .Sh DESCRIPTION
1.2 deraadt 87: .Nm
1.37 markus 88: generates, manages and converts authentication keys for
1.2 deraadt 89: .Xr ssh 1 .
1.15 deraadt 90: .Nm
1.54 deraadt 91: can create RSA keys for use by SSH protocol version 1 and RSA or DSA
1.52 djm 92: keys for use by SSH protocol version 2. The type of key to be generated
93: is specified with the
1.25 markus 94: .Fl t
1.52 djm 95: option.
1.15 deraadt 96: .Pp
1.2 deraadt 97: Normally each user wishing to use SSH
1.15 deraadt 98: with RSA or DSA authentication runs this once to create the authentication
1.1 deraadt 99: key in
1.36 itojun 100: .Pa $HOME/.ssh/identity ,
101: .Pa $HOME/.ssh/id_dsa
1.15 deraadt 102: or
1.36 itojun 103: .Pa $HOME/.ssh/id_rsa .
1.15 deraadt 104: Additionally, the system administrator may use this to generate host keys,
105: as seen in
106: .Pa /etc/rc .
1.2 deraadt 107: .Pp
1.1 deraadt 108: Normally this program generates the key and asks for a file in which
1.12 aaron 109: to store the private key.
110: The public key is stored in a file with the same name but
1.2 deraadt 111: .Dq .pub
1.12 aaron 112: appended.
113: The program also asks for a passphrase.
114: The passphrase may be empty to indicate no passphrase
1.26 markus 115: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 116: arbitrary length.
1.51 stevesk 117: A passphrase is similar to a password, except it can be a phrase with a
118: series of words, punctuation, numbers, whitespace, or any string of
119: characters you want.
120: Good passphrases are 10-30 characters long, are
1.1 deraadt 121: not simple sentences or otherwise easily guessable (English
1.42 markus 122: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 123: passphrases), and contain a mix of upper and lowercase letters,
124: numbers, and non-alphanumeric characters.
1.12 aaron 125: The passphrase can be changed later by using the
1.2 deraadt 126: .Fl p
1.1 deraadt 127: option.
1.2 deraadt 128: .Pp
1.12 aaron 129: There is no way to recover a lost passphrase.
130: If the passphrase is
1.49 deraadt 131: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 132: corresponding public key to other machines.
1.2 deraadt 133: .Pp
1.37 markus 134: For RSA1 keys,
135: there is also a comment field in the key file that is only for
1.12 aaron 136: convenience to the user to help identify the key.
137: The comment can tell what the key is for, or whatever is useful.
138: The comment is initialized to
1.2 deraadt 139: .Dq user@host
140: when the key is created, but can be changed using the
141: .Fl c
1.1 deraadt 142: option.
1.2 deraadt 143: .Pp
1.15 deraadt 144: After a key is generated, instructions below detail where the keys
145: should be placed to be activated.
146: .Pp
1.2 deraadt 147: The options are as follows:
148: .Bl -tag -width Ds
149: .It Fl b Ar bits
1.12 aaron 150: Specifies the number of bits in the key to create.
151: Minimum is 512 bits.
1.55 stevesk 152: Generally, 1024 bits is considered sufficient.
1.12 aaron 153: The default is 1024 bits.
1.2 deraadt 154: .It Fl c
1.1 deraadt 155: Requests changing the comment in the private and public key files.
1.50 markus 156: This operation is only supported for RSA1 keys.
1.1 deraadt 157: The program will prompt for the file containing the private keys, for
1.41 stevesk 158: the passphrase if the key has one, and for the new comment.
1.37 markus 159: .It Fl e
1.40 markus 160: This option will read a private or public OpenSSH key file and
161: print the key in a
1.37 markus 162: .Sq SECSH Public Key File Format
163: to stdout.
164: This option allows exporting keys for use by several commercial
165: SSH implementations.
1.48 jakob 166: .It Fl f Ar filename
1.9 markus 167: Specifies the filename of the key file.
1.37 markus 168: .It Fl i
169: This option will read an unencrypted private (or public) key file
170: in SSH2-compatible format and print an OpenSSH compatible private
171: (or public) key to stdout.
172: .Nm
1.38 markus 173: also reads the
1.37 markus 174: .Sq SECSH Public Key File Format .
175: This option allows importing keys from several commercial
176: SSH implementations.
1.9 markus 177: .It Fl l
1.50 markus 178: Show fingerprint of specified public key file.
179: Private RSA1 keys are also supported.
180: For RSA and DSA keys
181: .Nm
182: tries to find the matching public key file and prints its fingerprint.
1.2 deraadt 183: .It Fl p
1.1 deraadt 184: Requests changing the passphrase of a private key file instead of
1.12 aaron 185: creating a new private key.
186: The program will prompt for the file
1.1 deraadt 187: containing the private key, for the old passphrase, and twice for the
188: new passphrase.
1.5 aaron 189: .It Fl q
190: Silence
191: .Nm ssh-keygen .
192: Used by
193: .Pa /etc/rc
194: when creating a new key.
1.37 markus 195: .It Fl y
196: This option will read a private
197: OpenSSH format file and print an OpenSSH public key to stdout.
1.25 markus 198: .It Fl t Ar type
199: Specifies the type of the key to create.
200: The possible values are
201: .Dq rsa1
202: for protocol version 1 and
203: .Dq rsa
204: or
205: .Dq dsa
206: for protocol version 2.
1.35 markus 207: .It Fl B
208: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 209: .It Fl C Ar comment
1.1 deraadt 210: Provides the new comment.
1.48 jakob 211: .It Fl D Ar reader
212: Download the RSA public key stored in the smartcard in
213: .Ar reader .
1.2 deraadt 214: .It Fl N Ar new_passphrase
1.1 deraadt 215: Provides the new passphrase.
1.2 deraadt 216: .It Fl P Ar passphrase
1.1 deraadt 217: Provides the (old) passphrase.
1.48 jakob 218: .It Fl U Ar reader
219: Upload an existing RSA private key into the smartcard in
220: .Ar reader .
1.2 deraadt 221: .El
222: .Sh FILES
223: .Bl -tag -width Ds
224: .It Pa $HOME/.ssh/identity
1.36 itojun 225: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 226: This file should not be readable by anyone but the user.
227: It is possible to
1.1 deraadt 228: specify a passphrase when generating the key; that passphrase will be
1.12 aaron 229: used to encrypt the private part of this file using 3DES.
230: This file is not automatically accessed by
1.2 deraadt 231: .Nm
1.1 deraadt 232: but it is offered as the default file for the private key.
1.46 markus 233: .Xr ssh 1
1.15 deraadt 234: will read this file when a login attempt is made.
1.2 deraadt 235: .It Pa $HOME/.ssh/identity.pub
1.36 itojun 236: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 237: The contents of this file should be added to
1.2 deraadt 238: .Pa $HOME/.ssh/authorized_keys
239: on all machines
1.49 deraadt 240: where the user wishes to log in using RSA authentication.
1.15 deraadt 241: There is no need to keep the contents of this file secret.
242: .It Pa $HOME/.ssh/id_dsa
1.36 itojun 243: Contains the protocol version 2 DSA authentication identity of the user.
1.15 deraadt 244: This file should not be readable by anyone but the user.
245: It is possible to
246: specify a passphrase when generating the key; that passphrase will be
247: used to encrypt the private part of this file using 3DES.
248: This file is not automatically accessed by
249: .Nm
250: but it is offered as the default file for the private key.
1.46 markus 251: .Xr ssh 1
1.15 deraadt 252: will read this file when a login attempt is made.
253: .It Pa $HOME/.ssh/id_dsa.pub
1.36 itojun 254: Contains the protocol version 2 DSA public key for authentication.
255: The contents of this file should be added to
1.43 markus 256: .Pa $HOME/.ssh/authorized_keys
1.36 itojun 257: on all machines
1.49 deraadt 258: where the user wishes to log in using public key authentication.
1.36 itojun 259: There is no need to keep the contents of this file secret.
260: .It Pa $HOME/.ssh/id_rsa
261: Contains the protocol version 2 RSA authentication identity of the user.
262: This file should not be readable by anyone but the user.
263: It is possible to
264: specify a passphrase when generating the key; that passphrase will be
265: used to encrypt the private part of this file using 3DES.
266: This file is not automatically accessed by
267: .Nm
268: but it is offered as the default file for the private key.
1.46 markus 269: .Xr ssh 1
1.36 itojun 270: will read this file when a login attempt is made.
271: .It Pa $HOME/.ssh/id_rsa.pub
272: Contains the protocol version 2 RSA public key for authentication.
1.15 deraadt 273: The contents of this file should be added to
1.43 markus 274: .Pa $HOME/.ssh/authorized_keys
1.15 deraadt 275: on all machines
1.49 deraadt 276: where the user wishes to log in using public key authentication.
1.12 aaron 277: There is no need to keep the contents of this file secret.
1.19 aaron 278: .El
1.24 aaron 279: .Sh AUTHORS
1.28 markus 280: OpenSSH is a derivative of the original and free
281: ssh 1.2.12 release by Tatu Ylonen.
282: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
283: Theo de Raadt and Dug Song
284: removed many bugs, re-added newer features and
285: created OpenSSH.
286: Markus Friedl contributed the support for SSH
287: protocol versions 1.5 and 2.0.
1.2 deraadt 288: .Sh SEE ALSO
289: .Xr ssh 1 ,
290: .Xr ssh-add 1 ,
1.8 ericj 291: .Xr ssh-agent 1 ,
1.30 itojun 292: .Xr sshd 8
1.37 markus 293: .Rs
1.45 deraadt 294: .%A J. Galbraith
295: .%A R. Thayer
1.37 markus 296: .%T "SECSH Public Key File Format"
297: .%N draft-ietf-secsh-publickeyfile-01.txt
298: .%D March 2001
299: .%O work in progress material
300: .Re
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