Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.50
1.50 ! markus 1: .\" $OpenBSD: ssh-keygen.1,v 1.49 2001/09/05 06:23:07 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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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
1.49 deraadt 92: option instead creates 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
1.49 deraadt 124: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 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.
1.50 ! markus 150: This operation is only supported for RSA1 keys.
1.1 deraadt 151: The program will prompt for the file containing the private keys, for
1.41 stevesk 152: the passphrase if the key has one, and for the new comment.
1.37 markus 153: .It Fl e
1.40 markus 154: This option will read a private or public OpenSSH key file and
155: print the key in a
1.37 markus 156: .Sq SECSH Public Key File Format
157: to stdout.
158: This option allows exporting keys for use by several commercial
159: SSH implementations.
1.48 jakob 160: .It Fl f Ar filename
1.9 markus 161: Specifies the filename of the key file.
1.37 markus 162: .It Fl i
163: This option will read an unencrypted private (or public) key file
164: in SSH2-compatible format and print an OpenSSH compatible private
165: (or public) key to stdout.
166: .Nm
1.38 markus 167: also reads the
1.37 markus 168: .Sq SECSH Public Key File Format .
169: This option allows importing keys from several commercial
170: SSH implementations.
1.9 markus 171: .It Fl l
1.50 ! markus 172: Show fingerprint of specified public key file.
! 173: Private RSA1 keys are also supported.
! 174: For RSA and DSA keys
! 175: .Nm
! 176: tries to find the matching public key file and prints its fingerprint.
1.2 deraadt 177: .It Fl p
1.1 deraadt 178: Requests changing the passphrase of a private key file instead of
1.12 aaron 179: creating a new private key.
180: The program will prompt for the file
1.1 deraadt 181: containing the private key, for the old passphrase, and twice for the
182: new passphrase.
1.5 aaron 183: .It Fl q
184: Silence
185: .Nm ssh-keygen .
186: Used by
187: .Pa /etc/rc
188: when creating a new key.
1.37 markus 189: .It Fl y
190: This option will read a private
191: OpenSSH format file and print an OpenSSH public key to stdout.
1.25 markus 192: .It Fl t Ar type
193: Specifies the type of the key to create.
194: The possible values are
195: .Dq rsa1
196: for protocol version 1 and
197: .Dq rsa
198: or
199: .Dq dsa
200: for protocol version 2.
201: The default is
1.31 deraadt 202: .Dq rsa1 .
1.35 markus 203: .It Fl B
204: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 205: .It Fl C Ar comment
1.1 deraadt 206: Provides the new comment.
1.48 jakob 207: .It Fl D Ar reader
208: Download the RSA public key stored in the smartcard in
209: .Ar reader .
1.2 deraadt 210: .It Fl N Ar new_passphrase
1.1 deraadt 211: Provides the new passphrase.
1.2 deraadt 212: .It Fl P Ar passphrase
1.1 deraadt 213: Provides the (old) passphrase.
1.48 jakob 214: .It Fl U Ar reader
215: Upload an existing RSA private key into the smartcard in
216: .Ar reader .
1.2 deraadt 217: .El
218: .Sh FILES
219: .Bl -tag -width Ds
220: .It Pa $HOME/.ssh/identity
1.36 itojun 221: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 222: This file should not be readable by anyone but the user.
223: It is possible to
1.1 deraadt 224: specify a passphrase when generating the key; that passphrase will be
1.12 aaron 225: used to encrypt the private part of this file using 3DES.
226: This file is not automatically accessed by
1.2 deraadt 227: .Nm
1.1 deraadt 228: but it is offered as the default file for the private key.
1.46 markus 229: .Xr ssh 1
1.15 deraadt 230: will read this file when a login attempt is made.
1.2 deraadt 231: .It Pa $HOME/.ssh/identity.pub
1.36 itojun 232: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 233: The contents of this file should be added to
1.2 deraadt 234: .Pa $HOME/.ssh/authorized_keys
235: on all machines
1.49 deraadt 236: where the user wishes to log in using RSA authentication.
1.15 deraadt 237: There is no need to keep the contents of this file secret.
238: .It Pa $HOME/.ssh/id_dsa
1.36 itojun 239: Contains the protocol version 2 DSA authentication identity of the user.
1.15 deraadt 240: This file should not be readable by anyone but the user.
241: It is possible to
242: specify a passphrase when generating the key; that passphrase will be
243: used to encrypt the private part of this file using 3DES.
244: This file is not automatically accessed by
245: .Nm
246: but it is offered as the default file for the private key.
1.46 markus 247: .Xr ssh 1
1.15 deraadt 248: will read this file when a login attempt is made.
249: .It Pa $HOME/.ssh/id_dsa.pub
1.36 itojun 250: Contains the protocol version 2 DSA public key for authentication.
251: The contents of this file should be added to
1.43 markus 252: .Pa $HOME/.ssh/authorized_keys
1.36 itojun 253: on all machines
1.49 deraadt 254: where the user wishes to log in using public key authentication.
1.36 itojun 255: There is no need to keep the contents of this file secret.
256: .It Pa $HOME/.ssh/id_rsa
257: Contains the protocol version 2 RSA authentication identity of the user.
258: This file should not be readable by anyone but the user.
259: It is possible to
260: specify a passphrase when generating the key; that passphrase will be
261: used to encrypt the private part of this file using 3DES.
262: This file is not automatically accessed by
263: .Nm
264: but it is offered as the default file for the private key.
1.46 markus 265: .Xr ssh 1
1.36 itojun 266: will read this file when a login attempt is made.
267: .It Pa $HOME/.ssh/id_rsa.pub
268: Contains the protocol version 2 RSA public key for authentication.
1.15 deraadt 269: The contents of this file should be added to
1.43 markus 270: .Pa $HOME/.ssh/authorized_keys
1.15 deraadt 271: on all machines
1.49 deraadt 272: where the user wishes to log in using public key authentication.
1.12 aaron 273: There is no need to keep the contents of this file secret.
1.19 aaron 274: .El
1.24 aaron 275: .Sh AUTHORS
1.28 markus 276: OpenSSH is a derivative of the original and free
277: ssh 1.2.12 release by Tatu Ylonen.
278: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
279: Theo de Raadt and Dug Song
280: removed many bugs, re-added newer features and
281: created OpenSSH.
282: Markus Friedl contributed the support for SSH
283: protocol versions 1.5 and 2.0.
1.2 deraadt 284: .Sh SEE ALSO
285: .Xr ssh 1 ,
286: .Xr ssh-add 1 ,
1.8 ericj 287: .Xr ssh-agent 1 ,
1.30 itojun 288: .Xr sshd 8
1.37 markus 289: .Rs
1.45 deraadt 290: .%A J. Galbraith
291: .%A R. Thayer
1.37 markus 292: .%T "SECSH Public Key File Format"
293: .%N draft-ietf-secsh-publickeyfile-01.txt
294: .%D March 2001
295: .%O work in progress material
296: .Re
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