Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.55
1.55 ! stevesk 1: .\" $OpenBSD: ssh-keygen.1,v 1.54 2002/06/19 00:27:55 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,
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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
1.53 stevesk 50: .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
1.54 deraadt 89: can create RSA keys for use by SSH protocol version 1 and RSA or DSA
1.52 djm 90: keys for use by SSH protocol version 2. The type of key to be generated
91: is specified with the
1.25 markus 92: .Fl t
1.52 djm 93: option.
1.15 deraadt 94: .Pp
1.2 deraadt 95: Normally each user wishing to use SSH
1.15 deraadt 96: with RSA or DSA authentication runs this once to create the authentication
1.1 deraadt 97: key in
1.36 itojun 98: .Pa $HOME/.ssh/identity ,
99: .Pa $HOME/.ssh/id_dsa
1.15 deraadt 100: or
1.36 itojun 101: .Pa $HOME/.ssh/id_rsa .
1.15 deraadt 102: Additionally, the system administrator may use this to generate host keys,
103: as seen in
104: .Pa /etc/rc .
1.2 deraadt 105: .Pp
1.1 deraadt 106: Normally this program generates the key and asks for a file in which
1.12 aaron 107: to store the private key.
108: The public key is stored in a file with the same name but
1.2 deraadt 109: .Dq .pub
1.12 aaron 110: appended.
111: The program also asks for a passphrase.
112: The passphrase may be empty to indicate no passphrase
1.26 markus 113: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 114: arbitrary length.
1.51 stevesk 115: A passphrase is similar to a password, except it can be a phrase with a
116: series of words, punctuation, numbers, whitespace, or any string of
117: characters you want.
118: Good passphrases are 10-30 characters long, are
1.1 deraadt 119: not simple sentences or otherwise easily guessable (English
1.42 markus 120: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 121: passphrases), and contain a mix of upper and lowercase letters,
122: numbers, and non-alphanumeric characters.
1.12 aaron 123: The passphrase can be changed later by using the
1.2 deraadt 124: .Fl p
1.1 deraadt 125: option.
1.2 deraadt 126: .Pp
1.12 aaron 127: There is no way to recover a lost passphrase.
128: If the passphrase is
1.49 deraadt 129: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 130: corresponding public key to other machines.
1.2 deraadt 131: .Pp
1.37 markus 132: For RSA1 keys,
133: there is also a comment field in the key file that is only for
1.12 aaron 134: convenience to the user to help identify the key.
135: The comment can tell what the key is for, or whatever is useful.
136: The comment is initialized to
1.2 deraadt 137: .Dq user@host
138: when the key is created, but can be changed using the
139: .Fl c
1.1 deraadt 140: option.
1.2 deraadt 141: .Pp
1.15 deraadt 142: After a key is generated, instructions below detail where the keys
143: should be placed to be activated.
144: .Pp
1.2 deraadt 145: The options are as follows:
146: .Bl -tag -width Ds
147: .It Fl b Ar bits
1.12 aaron 148: Specifies the number of bits in the key to create.
149: Minimum is 512 bits.
1.55 ! stevesk 150: Generally, 1024 bits is considered sufficient.
1.12 aaron 151: The default is 1024 bits.
1.2 deraadt 152: .It Fl c
1.1 deraadt 153: Requests changing the comment in the private and public key files.
1.50 markus 154: This operation is only supported for RSA1 keys.
1.1 deraadt 155: The program will prompt for the file containing the private keys, for
1.41 stevesk 156: the passphrase if the key has one, and for the new comment.
1.37 markus 157: .It Fl e
1.40 markus 158: This option will read a private or public OpenSSH key file and
159: print the key in a
1.37 markus 160: .Sq SECSH Public Key File Format
161: to stdout.
162: This option allows exporting keys for use by several commercial
163: SSH implementations.
1.48 jakob 164: .It Fl f Ar filename
1.9 markus 165: Specifies the filename of the key file.
1.37 markus 166: .It Fl i
167: This option will read an unencrypted private (or public) key file
168: in SSH2-compatible format and print an OpenSSH compatible private
169: (or public) key to stdout.
170: .Nm
1.38 markus 171: also reads the
1.37 markus 172: .Sq SECSH Public Key File Format .
173: This option allows importing keys from several commercial
174: SSH implementations.
1.9 markus 175: .It Fl l
1.50 markus 176: Show fingerprint of specified public key file.
177: Private RSA1 keys are also supported.
178: For RSA and DSA keys
179: .Nm
180: tries to find the matching public key file and prints its fingerprint.
1.2 deraadt 181: .It Fl p
1.1 deraadt 182: Requests changing the passphrase of a private key file instead of
1.12 aaron 183: creating a new private key.
184: The program will prompt for the file
1.1 deraadt 185: containing the private key, for the old passphrase, and twice for the
186: new passphrase.
1.5 aaron 187: .It Fl q
188: Silence
189: .Nm ssh-keygen .
190: Used by
191: .Pa /etc/rc
192: when creating a new key.
1.37 markus 193: .It Fl y
194: This option will read a private
195: OpenSSH format file and print an OpenSSH public key to stdout.
1.25 markus 196: .It Fl t Ar type
197: Specifies the type of the key to create.
198: The possible values are
199: .Dq rsa1
200: for protocol version 1 and
201: .Dq rsa
202: or
203: .Dq dsa
204: for protocol version 2.
1.35 markus 205: .It Fl B
206: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 207: .It Fl C Ar comment
1.1 deraadt 208: Provides the new comment.
1.48 jakob 209: .It Fl D Ar reader
210: Download the RSA public key stored in the smartcard in
211: .Ar reader .
1.2 deraadt 212: .It Fl N Ar new_passphrase
1.1 deraadt 213: Provides the new passphrase.
1.2 deraadt 214: .It Fl P Ar passphrase
1.1 deraadt 215: Provides the (old) passphrase.
1.48 jakob 216: .It Fl U Ar reader
217: Upload an existing RSA private key into the smartcard in
218: .Ar reader .
1.2 deraadt 219: .El
220: .Sh FILES
221: .Bl -tag -width Ds
222: .It Pa $HOME/.ssh/identity
1.36 itojun 223: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 224: This file should not be readable by anyone but the user.
225: It is possible to
1.1 deraadt 226: specify a passphrase when generating the key; that passphrase will be
1.12 aaron 227: used to encrypt the private part of this file using 3DES.
228: This file is not automatically accessed by
1.2 deraadt 229: .Nm
1.1 deraadt 230: but it is offered as the default file for the private key.
1.46 markus 231: .Xr ssh 1
1.15 deraadt 232: will read this file when a login attempt is made.
1.2 deraadt 233: .It Pa $HOME/.ssh/identity.pub
1.36 itojun 234: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 235: The contents of this file should be added to
1.2 deraadt 236: .Pa $HOME/.ssh/authorized_keys
237: on all machines
1.49 deraadt 238: where the user wishes to log in using RSA authentication.
1.15 deraadt 239: There is no need to keep the contents of this file secret.
240: .It Pa $HOME/.ssh/id_dsa
1.36 itojun 241: Contains the protocol version 2 DSA authentication identity of the user.
1.15 deraadt 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.
1.46 markus 249: .Xr ssh 1
1.15 deraadt 250: will read this file when a login attempt is made.
251: .It Pa $HOME/.ssh/id_dsa.pub
1.36 itojun 252: Contains the protocol version 2 DSA public key for authentication.
253: The contents of this file should be added to
1.43 markus 254: .Pa $HOME/.ssh/authorized_keys
1.36 itojun 255: on all machines
1.49 deraadt 256: where the user wishes to log in using public key authentication.
1.36 itojun 257: There is no need to keep the contents of this file secret.
258: .It Pa $HOME/.ssh/id_rsa
259: Contains the protocol version 2 RSA authentication identity of the user.
260: This file should not be readable by anyone but the user.
261: It is possible to
262: specify a passphrase when generating the key; that passphrase will be
263: used to encrypt the private part of this file using 3DES.
264: This file is not automatically accessed by
265: .Nm
266: but it is offered as the default file for the private key.
1.46 markus 267: .Xr ssh 1
1.36 itojun 268: will read this file when a login attempt is made.
269: .It Pa $HOME/.ssh/id_rsa.pub
270: Contains the protocol version 2 RSA public key for authentication.
1.15 deraadt 271: The contents of this file should be added to
1.43 markus 272: .Pa $HOME/.ssh/authorized_keys
1.15 deraadt 273: on all machines
1.49 deraadt 274: where the user wishes to log in using public key authentication.
1.12 aaron 275: There is no need to keep the contents of this file secret.
1.19 aaron 276: .El
1.24 aaron 277: .Sh AUTHORS
1.28 markus 278: OpenSSH is a derivative of the original and free
279: ssh 1.2.12 release by Tatu Ylonen.
280: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
281: Theo de Raadt and Dug Song
282: removed many bugs, re-added newer features and
283: created OpenSSH.
284: Markus Friedl contributed the support for SSH
285: protocol versions 1.5 and 2.0.
1.2 deraadt 286: .Sh SEE ALSO
287: .Xr ssh 1 ,
288: .Xr ssh-add 1 ,
1.8 ericj 289: .Xr ssh-agent 1 ,
1.30 itojun 290: .Xr sshd 8
1.37 markus 291: .Rs
1.45 deraadt 292: .%A J. Galbraith
293: .%A R. Thayer
1.37 markus 294: .%T "SECSH Public Key File Format"
295: .%N draft-ietf-secsh-publickeyfile-01.txt
296: .%D March 2001
297: .%O work in progress material
298: .Re
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