Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.48
1.48 ! jakob 1: .\" $OpenBSD: ssh-keygen.1,v 1.47 2001/07/23 14:14:18 aaron 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
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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
1.25 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
1.37 markus 60: .Fl i
1.20 markus 61: .Op Fl f Ar input_keyfile
1.16 deraadt 62: .Nm ssh-keygen
1.37 markus 63: .Fl e
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
1.35 markus 75: .Op Fl f Ar input_keyfile
76: .Nm ssh-keygen
77: .Fl B
1.20 markus 78: .Op Fl f Ar input_keyfile
1.48 ! jakob 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
1.13 aaron 84: .Sh DESCRIPTION
1.2 deraadt 85: .Nm
1.37 markus 86: generates, manages and converts authentication keys for
1.2 deraadt 87: .Xr ssh 1 .
1.15 deraadt 88: .Nm
1.39 markus 89: defaults to generating a RSA1 key for use by SSH protocol version 1.
1.47 aaron 90: Specifying the
1.25 markus 91: .Fl t
1.39 markus 92: option allows you to create a key for use by SSH protocol version 2.
1.15 deraadt 93: .Pp
1.2 deraadt 94: Normally each user wishing to use SSH
1.15 deraadt 95: with RSA or DSA authentication runs this once to create the authentication
1.1 deraadt 96: key in
1.36 itojun 97: .Pa $HOME/.ssh/identity ,
98: .Pa $HOME/.ssh/id_dsa
1.15 deraadt 99: or
1.36 itojun 100: .Pa $HOME/.ssh/id_rsa .
1.15 deraadt 101: Additionally, the system administrator may use this to generate host keys,
102: as seen in
103: .Pa /etc/rc .
1.2 deraadt 104: .Pp
1.1 deraadt 105: Normally this program generates the key and asks for a file in which
1.12 aaron 106: to store the private key.
107: The public key is stored in a file with the same name but
1.2 deraadt 108: .Dq .pub
1.12 aaron 109: appended.
110: The program also asks for a passphrase.
111: The passphrase may be empty to indicate no passphrase
1.26 markus 112: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 113: arbitrary length.
114: Good passphrases are 10-30 characters long and are
1.1 deraadt 115: not simple sentences or otherwise easily guessable (English
1.42 markus 116: prose has only 1-2 bits of entropy per character, and provides very bad
1.12 aaron 117: passphrases).
118: The passphrase can be changed later by using the
1.2 deraadt 119: .Fl p
1.1 deraadt 120: option.
1.2 deraadt 121: .Pp
1.12 aaron 122: There is no way to recover a lost passphrase.
123: If the passphrase is
1.1 deraadt 124: lost or forgotten, you will have to generate a new key and copy the
125: corresponding public key to other machines.
1.2 deraadt 126: .Pp
1.37 markus 127: For RSA1 keys,
128: there is also a comment field in the key file that is only for
1.12 aaron 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
1.2 deraadt 132: .Dq user@host
133: when the key is created, but can be changed using the
134: .Fl c
1.1 deraadt 135: option.
1.2 deraadt 136: .Pp
1.15 deraadt 137: After a key is generated, instructions below detail where the keys
138: should be placed to be activated.
139: .Pp
1.2 deraadt 140: The options are as follows:
141: .Bl -tag -width Ds
142: .It Fl b Ar bits
1.12 aaron 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.
1.2 deraadt 148: .It Fl c
1.1 deraadt 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
1.41 stevesk 151: the passphrase if the key has one, and for the new comment.
1.37 markus 152: .It Fl e
1.40 markus 153: This option will read a private or public OpenSSH key file and
154: print the key in a
1.37 markus 155: .Sq SECSH Public Key File Format
156: to stdout.
157: This option allows exporting keys for use by several commercial
158: SSH implementations.
1.48 ! jakob 159: .It Fl f Ar filename
1.9 markus 160: Specifies the filename of the key file.
1.37 markus 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
1.38 markus 166: also reads the
1.37 markus 167: .Sq SECSH Public Key File Format .
168: This option allows importing keys from several commercial
169: SSH implementations.
1.9 markus 170: .It Fl l
171: Show fingerprint of specified private or public key file.
1.2 deraadt 172: .It Fl p
1.1 deraadt 173: Requests changing the passphrase of a private key file instead of
1.12 aaron 174: creating a new private key.
175: The program will prompt for the file
1.1 deraadt 176: containing the private key, for the old passphrase, and twice for the
177: new passphrase.
1.5 aaron 178: .It Fl q
179: Silence
180: .Nm ssh-keygen .
181: Used by
182: .Pa /etc/rc
183: when creating a new key.
1.37 markus 184: .It Fl y
185: This option will read a private
186: OpenSSH format file and print an OpenSSH public key to stdout.
1.25 markus 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
1.31 deraadt 197: .Dq rsa1 .
1.35 markus 198: .It Fl B
199: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 200: .It Fl C Ar comment
1.1 deraadt 201: Provides the new comment.
1.48 ! jakob 202: .It Fl D Ar reader
! 203: Download the RSA public key stored in the smartcard in
! 204: .Ar reader .
1.2 deraadt 205: .It Fl N Ar new_passphrase
1.1 deraadt 206: Provides the new passphrase.
1.2 deraadt 207: .It Fl P Ar passphrase
1.1 deraadt 208: Provides the (old) passphrase.
1.48 ! jakob 209: .It Fl U Ar reader
! 210: Upload an existing RSA private key into the smartcard in
! 211: .Ar reader .
1.2 deraadt 212: .El
213: .Sh FILES
214: .Bl -tag -width Ds
215: .It Pa $HOME/.ssh/identity
1.36 itojun 216: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 217: This file should not be readable by anyone but the user.
218: It is possible to
1.1 deraadt 219: specify a passphrase when generating the key; that passphrase will be
1.12 aaron 220: used to encrypt the private part of this file using 3DES.
221: This file is not automatically accessed by
1.2 deraadt 222: .Nm
1.1 deraadt 223: but it is offered as the default file for the private key.
1.46 markus 224: .Xr ssh 1
1.15 deraadt 225: will read this file when a login attempt is made.
1.2 deraadt 226: .It Pa $HOME/.ssh/identity.pub
1.36 itojun 227: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 228: The contents of this file should be added to
1.2 deraadt 229: .Pa $HOME/.ssh/authorized_keys
230: on all machines
1.12 aaron 231: where you wish to log in using RSA authentication.
1.15 deraadt 232: There is no need to keep the contents of this file secret.
233: .It Pa $HOME/.ssh/id_dsa
1.36 itojun 234: Contains the protocol version 2 DSA authentication identity of the user.
1.15 deraadt 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.
1.46 markus 242: .Xr ssh 1
1.15 deraadt 243: will read this file when a login attempt is made.
244: .It Pa $HOME/.ssh/id_dsa.pub
1.36 itojun 245: Contains the protocol version 2 DSA public key for authentication.
246: The contents of this file should be added to
1.43 markus 247: .Pa $HOME/.ssh/authorized_keys
1.36 itojun 248: on all machines
249: where you wish to log in using public key authentication.
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.
1.46 markus 260: .Xr ssh 1
1.36 itojun 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.
1.15 deraadt 264: The contents of this file should be added to
1.43 markus 265: .Pa $HOME/.ssh/authorized_keys
1.15 deraadt 266: on all machines
1.25 markus 267: where you wish to log in using public key authentication.
1.12 aaron 268: There is no need to keep the contents of this file secret.
1.19 aaron 269: .El
1.24 aaron 270: .Sh AUTHORS
1.28 markus 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.
1.2 deraadt 279: .Sh SEE ALSO
280: .Xr ssh 1 ,
281: .Xr ssh-add 1 ,
1.8 ericj 282: .Xr ssh-agent 1 ,
1.30 itojun 283: .Xr sshd 8
1.37 markus 284: .Rs
1.45 deraadt 285: .%A J. Galbraith
286: .%A R. Thayer
1.37 markus 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
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