Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.103
1.103 ! stevesk 1: .\" $OpenBSD: ssh-keygen.1,v 1.102 2011/03/23 15:16:22 stevesk Exp $
1.1 deraadt 2: .\"
3: .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
4: .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: .\" All rights reserved
6: .\"
1.22 deraadt 7: .\" As far as I am concerned, the code I have written for this software
8: .\" can be used freely for any purpose. Any derived versions of this
9: .\" software must be clearly marked as such, and if the derived work is
10: .\" incompatible with the protocol description in the RFC file, it must be
11: .\" called by a name other than "ssh" or "Secure Shell".
12: .\"
13: .\"
1.33 deraadt 14: .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
15: .\" Copyright (c) 1999 Aaron Campbell. All rights reserved.
16: .\" Copyright (c) 1999 Theo de Raadt. All rights reserved.
1.22 deraadt 17: .\"
18: .\" Redistribution and use in source and binary forms, with or without
19: .\" modification, are permitted provided that the following conditions
20: .\" are met:
21: .\" 1. Redistributions of source code must retain the above copyright
22: .\" notice, this list of conditions and the following disclaimer.
23: .\" 2. Redistributions in binary form must reproduce the above copyright
24: .\" notice, this list of conditions and the following disclaimer in the
25: .\" documentation and/or other materials provided with the distribution.
1.1 deraadt 26: .\"
1.22 deraadt 27: .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28: .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29: .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30: .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31: .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32: .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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36: .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 deraadt 37: .\"
1.103 ! stevesk 38: .Dd $Mdocdate: March 23 2011 $
1.2 deraadt 39: .Dt SSH-KEYGEN 1
40: .Os
41: .Sh NAME
42: .Nm ssh-keygen
1.37 markus 43: .Nd authentication key generation, management and conversion
1.2 deraadt 44: .Sh SYNOPSIS
1.97 schwarze 45: .Bk -words
1.2 deraadt 46: .Nm ssh-keygen
1.25 markus 47: .Op Fl q
1.2 deraadt 48: .Op Fl b Ar bits
1.53 stevesk 49: .Fl t Ar type
1.2 deraadt 50: .Op Fl N Ar new_passphrase
51: .Op Fl C Ar comment
1.20 markus 52: .Op Fl f Ar output_keyfile
1.2 deraadt 53: .Nm ssh-keygen
54: .Fl p
55: .Op Fl P Ar old_passphrase
56: .Op Fl N Ar new_passphrase
1.9 markus 57: .Op Fl f Ar keyfile
1.2 deraadt 58: .Nm ssh-keygen
1.37 markus 59: .Fl i
1.95 djm 60: .Op Fl m Ar key_format
1.20 markus 61: .Op Fl f Ar input_keyfile
1.16 deraadt 62: .Nm ssh-keygen
1.37 markus 63: .Fl e
1.95 djm 64: .Op Fl m Ar key_format
1.20 markus 65: .Op Fl f Ar input_keyfile
1.16 deraadt 66: .Nm ssh-keygen
1.17 markus 67: .Fl y
1.20 markus 68: .Op Fl f Ar input_keyfile
1.17 markus 69: .Nm ssh-keygen
1.2 deraadt 70: .Fl c
71: .Op Fl P Ar passphrase
72: .Op Fl C Ar comment
1.9 markus 73: .Op Fl f Ar keyfile
74: .Nm ssh-keygen
75: .Fl l
1.35 markus 76: .Op Fl f Ar input_keyfile
77: .Nm ssh-keygen
78: .Fl B
1.20 markus 79: .Op Fl f Ar input_keyfile
1.48 jakob 80: .Nm ssh-keygen
1.82 jmc 81: .Fl D Ar pkcs11
1.48 jakob 82: .Nm ssh-keygen
1.64 djm 83: .Fl F Ar hostname
84: .Op Fl f Ar known_hosts_file
1.79 sthen 85: .Op Fl l
1.64 djm 86: .Nm ssh-keygen
87: .Fl H
88: .Op Fl f Ar known_hosts_file
89: .Nm ssh-keygen
90: .Fl R Ar hostname
91: .Op Fl f Ar known_hosts_file
1.57 jakob 92: .Nm ssh-keygen
93: .Fl r Ar hostname
94: .Op Fl f Ar input_keyfile
95: .Op Fl g
1.60 djm 96: .Nm ssh-keygen
97: .Fl G Ar output_file
1.61 djm 98: .Op Fl v
1.60 djm 99: .Op Fl b Ar bits
100: .Op Fl M Ar memory
101: .Op Fl S Ar start_point
102: .Nm ssh-keygen
103: .Fl T Ar output_file
104: .Fl f Ar input_file
1.61 djm 105: .Op Fl v
1.60 djm 106: .Op Fl a Ar num_trials
107: .Op Fl W Ar generator
1.84 djm 108: .Nm ssh-keygen
109: .Fl s Ar ca_key
110: .Fl I Ar certificate_identity
111: .Op Fl h
112: .Op Fl n Ar principals
1.93 djm 113: .Op Fl O Ar option
1.84 djm 114: .Op Fl V Ar validity_interval
1.93 djm 115: .Op Fl z Ar serial_number
1.84 djm 116: .Ar
1.86 djm 117: .Nm ssh-keygen
118: .Fl L
119: .Op Fl f Ar input_keyfile
1.102 stevesk 120: .Nm ssh-keygen
121: .Fl A
1.85 jmc 122: .Ek
1.13 aaron 123: .Sh DESCRIPTION
1.2 deraadt 124: .Nm
1.37 markus 125: generates, manages and converts authentication keys for
1.2 deraadt 126: .Xr ssh 1 .
1.15 deraadt 127: .Nm
1.100 naddy 128: can create RSA keys for use by SSH protocol version 1 and DSA, ECDSA or RSA
1.58 jmc 129: keys for use by SSH protocol version 2.
130: The type of key to be generated is specified with the
1.25 markus 131: .Fl t
1.52 djm 132: option.
1.70 djm 133: If invoked without any arguments,
134: .Nm
1.71 jmc 135: will generate an RSA key for use in SSH protocol 2 connections.
1.15 deraadt 136: .Pp
1.60 djm 137: .Nm
138: is also used to generate groups for use in Diffie-Hellman group
139: exchange (DH-GEX).
140: See the
141: .Sx MODULI GENERATION
142: section for details.
143: .Pp
1.2 deraadt 144: Normally each user wishing to use SSH
1.99 djm 145: with public key authentication runs this once to create the authentication
1.1 deraadt 146: key in
1.68 djm 147: .Pa ~/.ssh/identity ,
1.99 djm 148: .Pa ~/.ssh/id_ecdsa ,
1.68 djm 149: .Pa ~/.ssh/id_dsa
1.15 deraadt 150: or
1.68 djm 151: .Pa ~/.ssh/id_rsa .
1.15 deraadt 152: Additionally, the system administrator may use this to generate host keys,
153: as seen in
154: .Pa /etc/rc .
1.2 deraadt 155: .Pp
1.1 deraadt 156: Normally this program generates the key and asks for a file in which
1.12 aaron 157: to store the private key.
158: The public key is stored in a file with the same name but
1.2 deraadt 159: .Dq .pub
1.12 aaron 160: appended.
161: The program also asks for a passphrase.
162: The passphrase may be empty to indicate no passphrase
1.26 markus 163: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 164: arbitrary length.
1.51 stevesk 165: A passphrase is similar to a password, except it can be a phrase with a
166: series of words, punctuation, numbers, whitespace, or any string of
167: characters you want.
168: Good passphrases are 10-30 characters long, are
1.1 deraadt 169: not simple sentences or otherwise easily guessable (English
1.42 markus 170: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 171: passphrases), and contain a mix of upper and lowercase letters,
172: numbers, and non-alphanumeric characters.
1.12 aaron 173: The passphrase can be changed later by using the
1.2 deraadt 174: .Fl p
1.1 deraadt 175: option.
1.2 deraadt 176: .Pp
1.12 aaron 177: There is no way to recover a lost passphrase.
178: If the passphrase is
1.49 deraadt 179: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 180: corresponding public key to other machines.
1.2 deraadt 181: .Pp
1.37 markus 182: For RSA1 keys,
183: there is also a comment field in the key file that is only for
1.12 aaron 184: convenience to the user to help identify the key.
185: The comment can tell what the key is for, or whatever is useful.
186: The comment is initialized to
1.2 deraadt 187: .Dq user@host
188: when the key is created, but can be changed using the
189: .Fl c
1.1 deraadt 190: option.
1.2 deraadt 191: .Pp
1.15 deraadt 192: After a key is generated, instructions below detail where the keys
193: should be placed to be activated.
194: .Pp
1.2 deraadt 195: The options are as follows:
196: .Bl -tag -width Ds
1.102 stevesk 197: .It Fl A
198: For each of the key types (rsa1, rsa, dsa and ecdsa) for which host keys
199: do not exist, generate the host keys with the default key file path,
200: an empty passphrase, default bits for the key type, and default comment.
201: This is used by
202: .Pa /etc/rc
203: to generate new host keys.
1.60 djm 204: .It Fl a Ar trials
205: Specifies the number of primality tests to perform when screening DH-GEX
206: candidates using the
207: .Fl T
208: command.
1.66 jmc 209: .It Fl B
210: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 211: .It Fl b Ar bits
1.12 aaron 212: Specifies the number of bits in the key to create.
1.72 dtucker 213: For RSA keys, the minimum size is 768 bits and the default is 2048 bits.
1.69 djm 214: Generally, 2048 bits is considered sufficient.
1.72 dtucker 215: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.66 jmc 216: .It Fl C Ar comment
217: Provides a new comment.
1.2 deraadt 218: .It Fl c
1.1 deraadt 219: Requests changing the comment in the private and public key files.
1.50 markus 220: This operation is only supported for RSA1 keys.
1.1 deraadt 221: The program will prompt for the file containing the private keys, for
1.41 stevesk 222: the passphrase if the key has one, and for the new comment.
1.81 markus 223: .It Fl D Ar pkcs11
1.83 markus 224: Download the RSA public keys provided by the PKCS#11 shared library
225: .Ar pkcs11 .
1.98 djm 226: When used in combination with
227: .Fl s ,
228: this option indicates that a CA key resides in a PKCS#11 token (see the
229: .Sx CERTIFICATES
230: section for details).
1.37 markus 231: .It Fl e
1.40 markus 232: This option will read a private or public OpenSSH key file and
1.95 djm 233: print to stdout the key in one of the formats specified by the
234: .Fl m
235: option.
236: The default export format is
237: .Dq RFC4716 .
1.96 jmc 238: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 239: several commercial SSH implementations.
1.66 jmc 240: .It Fl F Ar hostname
241: Search for the specified
242: .Ar hostname
243: in a
244: .Pa known_hosts
245: file, listing any occurrences found.
246: This option is useful to find hashed host names or addresses and may also be
247: used in conjunction with the
248: .Fl H
249: option to print found keys in a hashed format.
250: .It Fl f Ar filename
251: Specifies the filename of the key file.
252: .It Fl G Ar output_file
253: Generate candidate primes for DH-GEX.
254: These primes must be screened for
255: safety (using the
256: .Fl T
257: option) before use.
1.57 jakob 258: .It Fl g
1.62 jakob 259: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 260: .Fl r
1.62 jakob 261: command.
1.66 jmc 262: .It Fl H
263: Hash a
264: .Pa known_hosts
1.67 dtucker 265: file.
266: This replaces all hostnames and addresses with hashed representations
267: within the specified file; the original content is moved to a file with
268: a .old suffix.
1.66 jmc 269: These hashes may be used normally by
270: .Nm ssh
271: and
272: .Nm sshd ,
273: but they do not reveal identifying information should the file's contents
274: be disclosed.
275: This option will not modify existing hashed hostnames and is therefore safe
276: to use on files that mix hashed and non-hashed names.
1.84 djm 277: .It Fl h
278: When signing a key, create a host certificate instead of a user
279: certificate.
280: Please see the
281: .Sx CERTIFICATES
282: section for details.
1.85 jmc 283: .It Fl I Ar certificate_identity
1.84 djm 284: Specify the key identity when signing a public key.
285: Please see the
286: .Sx CERTIFICATES
287: section for details.
1.37 markus 288: .It Fl i
289: This option will read an unencrypted private (or public) key file
1.95 djm 290: in the format specified by the
291: .Fl m
292: option and print an OpenSSH compatible private
1.37 markus 293: (or public) key to stdout.
1.95 djm 294: This option allows importing keys from other software, including several
295: commercial SSH implementations.
296: The default import format is
297: .Dq RFC4716 .
1.86 djm 298: .It Fl L
299: Prints the contents of a certificate.
1.9 markus 300: .It Fl l
1.77 grunk 301: Show fingerprint of specified public key file.
1.50 markus 302: Private RSA1 keys are also supported.
303: For RSA and DSA keys
304: .Nm
1.78 jmc 305: tries to find the matching public key file and prints its fingerprint.
306: If combined with
307: .Fl v ,
308: an ASCII art representation of the key is supplied with the fingerprint.
1.96 jmc 309: .It Fl M Ar memory
310: Specify the amount of memory to use (in megabytes) when generating
311: candidate moduli for DH-GEX.
1.95 djm 312: .It Fl m Ar key_format
313: Specify a key format for the
314: .Fl i
315: (import) or
316: .Fl e
1.96 jmc 317: (export) conversion options.
1.95 djm 318: The supported key formats are:
319: .Dq RFC4716
1.96 jmc 320: (RFC 4716/SSH2 public or private key),
1.95 djm 321: .Dq PKCS8
322: (PEM PKCS8 public key)
323: or
324: .Dq PEM
325: (PEM public key).
326: The default conversion format is
327: .Dq RFC4716 .
1.66 jmc 328: .It Fl N Ar new_passphrase
329: Provides the new passphrase.
1.84 djm 330: .It Fl n Ar principals
331: Specify one or more principals (user or host names) to be included in
332: a certificate when signing a key.
333: Multiple principals may be specified, separated by commas.
334: Please see the
335: .Sx CERTIFICATES
336: section for details.
1.93 djm 337: .It Fl O Ar option
338: Specify a certificate option when signing a key.
1.84 djm 339: This option may be specified multiple times.
340: Please see the
341: .Sx CERTIFICATES
342: section for details.
1.93 djm 343: The options that are valid for user certificates are:
1.84 djm 344: .Bl -tag -width Ds
1.89 jmc 345: .It Ic clear
346: Clear all enabled permissions.
347: This is useful for clearing the default set of permissions so permissions may
348: be added individually.
349: .It Ic force-command Ns = Ns Ar command
350: Forces the execution of
351: .Ar command
352: instead of any shell or command specified by the user when
353: the certificate is used for authentication.
1.84 djm 354: .It Ic no-agent-forwarding
355: Disable
356: .Xr ssh-agent 1
1.85 jmc 357: forwarding (permitted by default).
1.84 djm 358: .It Ic no-port-forwarding
1.85 jmc 359: Disable port forwarding (permitted by default).
1.84 djm 360: .It Ic no-pty
1.85 jmc 361: Disable PTY allocation (permitted by default).
1.84 djm 362: .It Ic no-user-rc
363: Disable execution of
364: .Pa ~/.ssh/rc
365: by
1.85 jmc 366: .Xr sshd 8
367: (permitted by default).
1.89 jmc 368: .It Ic no-x11-forwarding
369: Disable X11 forwarding (permitted by default).
1.88 djm 370: .It Ic permit-agent-forwarding
371: Allows
372: .Xr ssh-agent 1
373: forwarding.
1.84 djm 374: .It Ic permit-port-forwarding
375: Allows port forwarding.
376: .It Ic permit-pty
377: Allows PTY allocation.
378: .It Ic permit-user-rc
379: Allows execution of
380: .Pa ~/.ssh/rc
381: by
382: .Xr sshd 8 .
1.89 jmc 383: .It Ic permit-x11-forwarding
384: Allows X11 forwarding.
385: .It Ic source-address Ns = Ns Ar address_list
1.90 jmc 386: Restrict the source addresses from which the certificate is considered valid.
1.84 djm 387: The
388: .Ar address_list
389: is a comma-separated list of one or more address/netmask pairs in CIDR
390: format.
391: .El
392: .Pp
1.93 djm 393: At present, no options are valid for host keys.
1.66 jmc 394: .It Fl P Ar passphrase
395: Provides the (old) passphrase.
1.2 deraadt 396: .It Fl p
1.1 deraadt 397: Requests changing the passphrase of a private key file instead of
1.12 aaron 398: creating a new private key.
399: The program will prompt for the file
1.1 deraadt 400: containing the private key, for the old passphrase, and twice for the
401: new passphrase.
1.5 aaron 402: .It Fl q
403: Silence
404: .Nm ssh-keygen .
1.64 djm 405: .It Fl R Ar hostname
406: Removes all keys belonging to
407: .Ar hostname
1.65 jmc 408: from a
1.64 djm 409: .Pa known_hosts
410: file.
1.65 jmc 411: This option is useful to delete hashed hosts (see the
1.64 djm 412: .Fl H
413: option above).
1.66 jmc 414: .It Fl r Ar hostname
415: Print the SSHFP fingerprint resource record named
416: .Ar hostname
417: for the specified public key file.
1.60 djm 418: .It Fl S Ar start
419: Specify start point (in hex) when generating candidate moduli for DH-GEX.
1.84 djm 420: .It Fl s Ar ca_key
421: Certify (sign) a public key using the specified CA key.
422: Please see the
423: .Sx CERTIFICATES
424: section for details.
1.60 djm 425: .It Fl T Ar output_file
426: Test DH group exchange candidate primes (generated using the
427: .Fl G
428: option) for safety.
1.66 jmc 429: .It Fl t Ar type
430: Specifies the type of key to create.
431: The possible values are
432: .Dq rsa1
433: for protocol version 1 and
1.100 naddy 434: .Dq dsa ,
435: .Dq ecdsa
436: or
1.66 jmc 437: .Dq rsa
438: for protocol version 2.
1.84 djm 439: .It Fl V Ar validity_interval
440: Specify a validity interval when signing a certificate.
441: A validity interval may consist of a single time, indicating that the
442: certificate is valid beginning now and expiring at that time, or may consist
443: of two times separated by a colon to indicate an explicit time interval.
444: The start time may be specified as a date in YYYYMMDD format, a time
445: in YYYYMMDDHHMMSS format or a relative time (to the current time) consisting
446: of a minus sign followed by a relative time in the format described in the
447: .Sx TIME FORMATS
448: section of
1.90 jmc 449: .Xr sshd_config 5 .
1.84 djm 450: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMMSS time or
451: a relative time starting with a plus character.
452: .Pp
453: For example:
454: .Dq +52w1d
455: (valid from now to 52 weeks and one day from now),
456: .Dq -4w:+4w
457: (valid from four weeks ago to four weeks from now),
458: .Dq 20100101123000:20110101123000
459: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
460: .Dq -1d:20110101
461: (valid from yesterday to midnight, January 1st, 2011).
1.61 djm 462: .It Fl v
463: Verbose mode.
464: Causes
465: .Nm
466: to print debugging messages about its progress.
467: This is helpful for debugging moduli generation.
468: Multiple
469: .Fl v
470: options increase the verbosity.
471: The maximum is 3.
1.66 jmc 472: .It Fl W Ar generator
473: Specify desired generator when testing candidate moduli for DH-GEX.
474: .It Fl y
475: This option will read a private
476: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 477: .It Fl z Ar serial_number
478: Specifies a serial number to be embedded in the certificate to distinguish
479: this certificate from others from the same CA.
480: The default serial number is zero.
1.2 deraadt 481: .El
1.60 djm 482: .Sh MODULI GENERATION
483: .Nm
484: may be used to generate groups for the Diffie-Hellman Group Exchange
485: (DH-GEX) protocol.
486: Generating these groups is a two-step process: first, candidate
487: primes are generated using a fast, but memory intensive process.
488: These candidate primes are then tested for suitability (a CPU-intensive
489: process).
490: .Pp
491: Generation of primes is performed using the
492: .Fl G
493: option.
494: The desired length of the primes may be specified by the
495: .Fl b
496: option.
497: For example:
498: .Pp
1.66 jmc 499: .Dl # ssh-keygen -G moduli-2048.candidates -b 2048
1.60 djm 500: .Pp
501: By default, the search for primes begins at a random point in the
502: desired length range.
503: This may be overridden using the
504: .Fl S
505: option, which specifies a different start point (in hex).
506: .Pp
507: Once a set of candidates have been generated, they must be tested for
508: suitability.
509: This may be performed using the
510: .Fl T
511: option.
512: In this mode
513: .Nm
514: will read candidates from standard input (or a file specified using the
515: .Fl f
516: option).
517: For example:
518: .Pp
1.66 jmc 519: .Dl # ssh-keygen -T moduli-2048 -f moduli-2048.candidates
1.60 djm 520: .Pp
521: By default, each candidate will be subjected to 100 primality tests.
522: This may be overridden using the
523: .Fl a
524: option.
525: The DH generator value will be chosen automatically for the
526: prime under consideration.
527: If a specific generator is desired, it may be requested using the
528: .Fl W
529: option.
1.66 jmc 530: Valid generator values are 2, 3, and 5.
1.60 djm 531: .Pp
532: Screened DH groups may be installed in
533: .Pa /etc/moduli .
534: It is important that this file contains moduli of a range of bit lengths and
535: that both ends of a connection share common moduli.
1.84 djm 536: .Sh CERTIFICATES
537: .Nm
538: supports signing of keys to produce certificates that may be used for
539: user or host authentication.
540: Certificates consist of a public key, some identity information, zero or
1.94 jmc 541: more principal (user or host) names and a set of options that
1.84 djm 542: are signed by a Certification Authority (CA) key.
543: Clients or servers may then trust only the CA key and verify its signature
544: on a certificate rather than trusting many user/host keys.
545: Note that OpenSSH certificates are a different, and much simpler, format to
546: the X.509 certificates used in
547: .Xr ssl 8 .
548: .Pp
549: .Nm
550: supports two types of certificates: user and host.
551: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 552: authenticate server hosts to users.
553: To generate a user certificate:
1.84 djm 554: .Pp
555: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
556: .Pp
557: The resultant certificate will be placed in
1.91 djm 558: .Pa /path/to/user_key-cert.pub .
1.84 djm 559: A host certificate requires the
560: .Fl h
561: option:
562: .Pp
563: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
564: .Pp
565: The host certificate will be output to
1.91 djm 566: .Pa /path/to/host_key-cert.pub .
1.98 djm 567: .Pp
568: It is possible to sign using a CA key stored in a PKCS#11 token by
569: providing the token library using
570: .Fl D
571: and identifying the CA key by providing its public half as an argument
572: to
573: .Fl s :
574: .Pp
575: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id host_key.pub
576: .Pp
577: In all cases,
1.84 djm 578: .Ar key_id
579: is a "key identifier" that is logged by the server when the certificate
580: is used for authentication.
581: .Pp
582: Certificates may be limited to be valid for a set of principal (user/host)
583: names.
584: By default, generated certificates are valid for all users or hosts.
585: To generate a certificate for a specified set of principals:
586: .Pp
587: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.92 jmc 588: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub"
1.84 djm 589: .Pp
590: Additional limitations on the validity and use of user certificates may
1.94 jmc 591: be specified through certificate options.
1.93 djm 592: A certificate option may disable features of the SSH session, may be
1.84 djm 593: valid only when presented from particular source addresses or may
594: force the use of a specific command.
1.93 djm 595: For a list of valid certificate options, see the documentation for the
1.84 djm 596: .Fl O
597: option above.
598: .Pp
599: Finally, certificates may be defined with a validity lifetime.
600: The
601: .Fl V
602: option allows specification of certificate start and end times.
603: A certificate that is presented at a time outside this range will not be
604: considered valid.
605: By default, certificates have a maximum validity interval.
606: .Pp
607: For certificates to be used for user or host authentication, the CA
608: public key must be trusted by
609: .Xr sshd 8
610: or
611: .Xr ssh 1 .
612: Please refer to those manual pages for details.
1.2 deraadt 613: .Sh FILES
1.100 naddy 614: .Bl -tag -width Ds -compact
1.68 djm 615: .It Pa ~/.ssh/identity
1.36 itojun 616: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 617: This file should not be readable by anyone but the user.
618: It is possible to
1.1 deraadt 619: specify a passphrase when generating the key; that passphrase will be
1.100 naddy 620: used to encrypt the private part of this file using 3DES.
1.12 aaron 621: This file is not automatically accessed by
1.2 deraadt 622: .Nm
1.1 deraadt 623: but it is offered as the default file for the private key.
1.46 markus 624: .Xr ssh 1
1.15 deraadt 625: will read this file when a login attempt is made.
1.100 naddy 626: .Pp
1.68 djm 627: .It Pa ~/.ssh/identity.pub
1.36 itojun 628: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 629: The contents of this file should be added to
1.68 djm 630: .Pa ~/.ssh/authorized_keys
1.2 deraadt 631: on all machines
1.49 deraadt 632: where the user wishes to log in using RSA authentication.
1.15 deraadt 633: There is no need to keep the contents of this file secret.
1.100 naddy 634: .Pp
1.68 djm 635: .It Pa ~/.ssh/id_dsa
1.100 naddy 636: .It Pa ~/.ssh/id_ecdsa
637: .It Pa ~/.ssh/id_rsa
638: Contains the protocol version 2 DSA, ECDSA or RSA authentication identity of the user.
1.15 deraadt 639: This file should not be readable by anyone but the user.
640: It is possible to
641: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 642: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 643: This file is not automatically accessed by
644: .Nm
645: but it is offered as the default file for the private key.
1.46 markus 646: .Xr ssh 1
1.15 deraadt 647: will read this file when a login attempt is made.
1.100 naddy 648: .Pp
1.68 djm 649: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 650: .It Pa ~/.ssh/id_ecdsa.pub
1.68 djm 651: .It Pa ~/.ssh/id_rsa.pub
1.100 naddy 652: Contains the protocol version 2 DSA, ECDSA or RSA public key for authentication.
1.15 deraadt 653: The contents of this file should be added to
1.68 djm 654: .Pa ~/.ssh/authorized_keys
1.15 deraadt 655: on all machines
1.49 deraadt 656: where the user wishes to log in using public key authentication.
1.12 aaron 657: There is no need to keep the contents of this file secret.
1.100 naddy 658: .Pp
1.60 djm 659: .It Pa /etc/moduli
660: Contains Diffie-Hellman groups used for DH-GEX.
661: The file format is described in
662: .Xr moduli 5 .
1.19 aaron 663: .El
1.2 deraadt 664: .Sh SEE ALSO
665: .Xr ssh 1 ,
666: .Xr ssh-add 1 ,
1.8 ericj 667: .Xr ssh-agent 1 ,
1.60 djm 668: .Xr moduli 5 ,
1.30 itojun 669: .Xr sshd 8
1.37 markus 670: .Rs
1.73 markus 671: .%R RFC 4716
672: .%T "The Secure Shell (SSH) Public Key File Format"
673: .%D 2006
1.37 markus 674: .Re
1.59 jmc 675: .Sh AUTHORS
676: OpenSSH is a derivative of the original and free
677: ssh 1.2.12 release by Tatu Ylonen.
678: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
679: Theo de Raadt and Dug Song
680: removed many bugs, re-added newer features and
681: created OpenSSH.
682: Markus Friedl contributed the support for SSH
683: protocol versions 1.5 and 2.0.
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