Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.105
1.105 ! djm 1: .\" $OpenBSD: ssh-keygen.1,v 1.104 2011/03/24 15:29:30 jmc 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,
33: .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34: .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35: .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36: .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 deraadt 37: .\"
1.105 ! djm 38: .Dd $Mdocdate: March 24 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.
1.105 ! djm 178: If the passphrase is lost or forgotten, a new key must be generated
! 179: and the corresponding public key copied to other machines.
1.2 deraadt 180: .Pp
1.37 markus 181: For RSA1 keys,
182: there is also a comment field in the key file that is only for
1.12 aaron 183: convenience to the user to help identify the key.
184: The comment can tell what the key is for, or whatever is useful.
185: The comment is initialized to
1.2 deraadt 186: .Dq user@host
187: when the key is created, but can be changed using the
188: .Fl c
1.1 deraadt 189: option.
1.2 deraadt 190: .Pp
1.15 deraadt 191: After a key is generated, instructions below detail where the keys
192: should be placed to be activated.
193: .Pp
1.2 deraadt 194: The options are as follows:
195: .Bl -tag -width Ds
1.102 stevesk 196: .It Fl A
197: For each of the key types (rsa1, rsa, dsa and ecdsa) for which host keys
198: do not exist, generate the host keys with the default key file path,
199: an empty passphrase, default bits for the key type, and default comment.
1.104 jmc 200: This is used by
1.102 stevesk 201: .Pa /etc/rc
202: to generate new host keys.
1.60 djm 203: .It Fl a Ar trials
204: Specifies the number of primality tests to perform when screening DH-GEX
205: candidates using the
206: .Fl T
207: command.
1.66 jmc 208: .It Fl B
209: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 210: .It Fl b Ar bits
1.12 aaron 211: Specifies the number of bits in the key to create.
1.72 dtucker 212: For RSA keys, the minimum size is 768 bits and the default is 2048 bits.
1.69 djm 213: Generally, 2048 bits is considered sufficient.
1.72 dtucker 214: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.66 jmc 215: .It Fl C Ar comment
216: Provides a new comment.
1.2 deraadt 217: .It Fl c
1.1 deraadt 218: Requests changing the comment in the private and public key files.
1.50 markus 219: This operation is only supported for RSA1 keys.
1.1 deraadt 220: The program will prompt for the file containing the private keys, for
1.41 stevesk 221: the passphrase if the key has one, and for the new comment.
1.81 markus 222: .It Fl D Ar pkcs11
1.83 markus 223: Download the RSA public keys provided by the PKCS#11 shared library
224: .Ar pkcs11 .
1.98 djm 225: When used in combination with
226: .Fl s ,
227: this option indicates that a CA key resides in a PKCS#11 token (see the
228: .Sx CERTIFICATES
229: section for details).
1.37 markus 230: .It Fl e
1.40 markus 231: This option will read a private or public OpenSSH key file and
1.95 djm 232: print to stdout the key in one of the formats specified by the
233: .Fl m
234: option.
235: The default export format is
236: .Dq RFC4716 .
1.96 jmc 237: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 238: several commercial SSH implementations.
1.66 jmc 239: .It Fl F Ar hostname
240: Search for the specified
241: .Ar hostname
242: in a
243: .Pa known_hosts
244: file, listing any occurrences found.
245: This option is useful to find hashed host names or addresses and may also be
246: used in conjunction with the
247: .Fl H
248: option to print found keys in a hashed format.
249: .It Fl f Ar filename
250: Specifies the filename of the key file.
251: .It Fl G Ar output_file
252: Generate candidate primes for DH-GEX.
253: These primes must be screened for
254: safety (using the
255: .Fl T
256: option) before use.
1.57 jakob 257: .It Fl g
1.62 jakob 258: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 259: .Fl r
1.62 jakob 260: command.
1.66 jmc 261: .It Fl H
262: Hash a
263: .Pa known_hosts
1.67 dtucker 264: file.
265: This replaces all hostnames and addresses with hashed representations
266: within the specified file; the original content is moved to a file with
267: a .old suffix.
1.66 jmc 268: These hashes may be used normally by
269: .Nm ssh
270: and
271: .Nm sshd ,
272: but they do not reveal identifying information should the file's contents
273: be disclosed.
274: This option will not modify existing hashed hostnames and is therefore safe
275: to use on files that mix hashed and non-hashed names.
1.84 djm 276: .It Fl h
277: When signing a key, create a host certificate instead of a user
278: certificate.
279: Please see the
280: .Sx CERTIFICATES
281: section for details.
1.85 jmc 282: .It Fl I Ar certificate_identity
1.84 djm 283: Specify the key identity when signing a public key.
284: Please see the
285: .Sx CERTIFICATES
286: section for details.
1.37 markus 287: .It Fl i
288: This option will read an unencrypted private (or public) key file
1.95 djm 289: in the format specified by the
290: .Fl m
291: option and print an OpenSSH compatible private
1.37 markus 292: (or public) key to stdout.
1.95 djm 293: This option allows importing keys from other software, including several
294: commercial SSH implementations.
295: The default import format is
296: .Dq RFC4716 .
1.86 djm 297: .It Fl L
298: Prints the contents of a certificate.
1.9 markus 299: .It Fl l
1.77 grunk 300: Show fingerprint of specified public key file.
1.50 markus 301: Private RSA1 keys are also supported.
302: For RSA and DSA keys
303: .Nm
1.78 jmc 304: tries to find the matching public key file and prints its fingerprint.
305: If combined with
306: .Fl v ,
307: an ASCII art representation of the key is supplied with the fingerprint.
1.96 jmc 308: .It Fl M Ar memory
309: Specify the amount of memory to use (in megabytes) when generating
310: candidate moduli for DH-GEX.
1.95 djm 311: .It Fl m Ar key_format
312: Specify a key format for the
313: .Fl i
314: (import) or
315: .Fl e
1.96 jmc 316: (export) conversion options.
1.95 djm 317: The supported key formats are:
318: .Dq RFC4716
1.96 jmc 319: (RFC 4716/SSH2 public or private key),
1.95 djm 320: .Dq PKCS8
321: (PEM PKCS8 public key)
322: or
323: .Dq PEM
324: (PEM public key).
325: The default conversion format is
326: .Dq RFC4716 .
1.66 jmc 327: .It Fl N Ar new_passphrase
328: Provides the new passphrase.
1.84 djm 329: .It Fl n Ar principals
330: Specify one or more principals (user or host names) to be included in
331: a certificate when signing a key.
332: Multiple principals may be specified, separated by commas.
333: Please see the
334: .Sx CERTIFICATES
335: section for details.
1.93 djm 336: .It Fl O Ar option
337: Specify a certificate option when signing a key.
1.84 djm 338: This option may be specified multiple times.
339: Please see the
340: .Sx CERTIFICATES
341: section for details.
1.93 djm 342: The options that are valid for user certificates are:
1.84 djm 343: .Bl -tag -width Ds
1.89 jmc 344: .It Ic clear
345: Clear all enabled permissions.
346: This is useful for clearing the default set of permissions so permissions may
347: be added individually.
348: .It Ic force-command Ns = Ns Ar command
349: Forces the execution of
350: .Ar command
351: instead of any shell or command specified by the user when
352: the certificate is used for authentication.
1.84 djm 353: .It Ic no-agent-forwarding
354: Disable
355: .Xr ssh-agent 1
1.85 jmc 356: forwarding (permitted by default).
1.84 djm 357: .It Ic no-port-forwarding
1.85 jmc 358: Disable port forwarding (permitted by default).
1.84 djm 359: .It Ic no-pty
1.85 jmc 360: Disable PTY allocation (permitted by default).
1.84 djm 361: .It Ic no-user-rc
362: Disable execution of
363: .Pa ~/.ssh/rc
364: by
1.85 jmc 365: .Xr sshd 8
366: (permitted by default).
1.89 jmc 367: .It Ic no-x11-forwarding
368: Disable X11 forwarding (permitted by default).
1.88 djm 369: .It Ic permit-agent-forwarding
370: Allows
371: .Xr ssh-agent 1
372: forwarding.
1.84 djm 373: .It Ic permit-port-forwarding
374: Allows port forwarding.
375: .It Ic permit-pty
376: Allows PTY allocation.
377: .It Ic permit-user-rc
378: Allows execution of
379: .Pa ~/.ssh/rc
380: by
381: .Xr sshd 8 .
1.89 jmc 382: .It Ic permit-x11-forwarding
383: Allows X11 forwarding.
384: .It Ic source-address Ns = Ns Ar address_list
1.90 jmc 385: Restrict the source addresses from which the certificate is considered valid.
1.84 djm 386: The
387: .Ar address_list
388: is a comma-separated list of one or more address/netmask pairs in CIDR
389: format.
390: .El
391: .Pp
1.93 djm 392: At present, no options are valid for host keys.
1.66 jmc 393: .It Fl P Ar passphrase
394: Provides the (old) passphrase.
1.2 deraadt 395: .It Fl p
1.1 deraadt 396: Requests changing the passphrase of a private key file instead of
1.12 aaron 397: creating a new private key.
398: The program will prompt for the file
1.1 deraadt 399: containing the private key, for the old passphrase, and twice for the
400: new passphrase.
1.5 aaron 401: .It Fl q
402: Silence
403: .Nm ssh-keygen .
1.64 djm 404: .It Fl R Ar hostname
405: Removes all keys belonging to
406: .Ar hostname
1.65 jmc 407: from a
1.64 djm 408: .Pa known_hosts
409: file.
1.65 jmc 410: This option is useful to delete hashed hosts (see the
1.64 djm 411: .Fl H
412: option above).
1.66 jmc 413: .It Fl r Ar hostname
414: Print the SSHFP fingerprint resource record named
415: .Ar hostname
416: for the specified public key file.
1.60 djm 417: .It Fl S Ar start
418: Specify start point (in hex) when generating candidate moduli for DH-GEX.
1.84 djm 419: .It Fl s Ar ca_key
420: Certify (sign) a public key using the specified CA key.
421: Please see the
422: .Sx CERTIFICATES
423: section for details.
1.60 djm 424: .It Fl T Ar output_file
425: Test DH group exchange candidate primes (generated using the
426: .Fl G
427: option) for safety.
1.66 jmc 428: .It Fl t Ar type
429: Specifies the type of key to create.
430: The possible values are
431: .Dq rsa1
432: for protocol version 1 and
1.100 naddy 433: .Dq dsa ,
434: .Dq ecdsa
435: or
1.66 jmc 436: .Dq rsa
437: for protocol version 2.
1.84 djm 438: .It Fl V Ar validity_interval
439: Specify a validity interval when signing a certificate.
440: A validity interval may consist of a single time, indicating that the
441: certificate is valid beginning now and expiring at that time, or may consist
442: of two times separated by a colon to indicate an explicit time interval.
443: The start time may be specified as a date in YYYYMMDD format, a time
444: in YYYYMMDDHHMMSS format or a relative time (to the current time) consisting
445: of a minus sign followed by a relative time in the format described in the
446: .Sx TIME FORMATS
447: section of
1.90 jmc 448: .Xr sshd_config 5 .
1.84 djm 449: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMMSS time or
450: a relative time starting with a plus character.
451: .Pp
452: For example:
453: .Dq +52w1d
454: (valid from now to 52 weeks and one day from now),
455: .Dq -4w:+4w
456: (valid from four weeks ago to four weeks from now),
457: .Dq 20100101123000:20110101123000
458: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
459: .Dq -1d:20110101
460: (valid from yesterday to midnight, January 1st, 2011).
1.61 djm 461: .It Fl v
462: Verbose mode.
463: Causes
464: .Nm
465: to print debugging messages about its progress.
466: This is helpful for debugging moduli generation.
467: Multiple
468: .Fl v
469: options increase the verbosity.
470: The maximum is 3.
1.66 jmc 471: .It Fl W Ar generator
472: Specify desired generator when testing candidate moduli for DH-GEX.
473: .It Fl y
474: This option will read a private
475: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 476: .It Fl z Ar serial_number
477: Specifies a serial number to be embedded in the certificate to distinguish
478: this certificate from others from the same CA.
479: The default serial number is zero.
1.2 deraadt 480: .El
1.60 djm 481: .Sh MODULI GENERATION
482: .Nm
483: may be used to generate groups for the Diffie-Hellman Group Exchange
484: (DH-GEX) protocol.
485: Generating these groups is a two-step process: first, candidate
486: primes are generated using a fast, but memory intensive process.
487: These candidate primes are then tested for suitability (a CPU-intensive
488: process).
489: .Pp
490: Generation of primes is performed using the
491: .Fl G
492: option.
493: The desired length of the primes may be specified by the
494: .Fl b
495: option.
496: For example:
497: .Pp
1.66 jmc 498: .Dl # ssh-keygen -G moduli-2048.candidates -b 2048
1.60 djm 499: .Pp
500: By default, the search for primes begins at a random point in the
501: desired length range.
502: This may be overridden using the
503: .Fl S
504: option, which specifies a different start point (in hex).
505: .Pp
506: Once a set of candidates have been generated, they must be tested for
507: suitability.
508: This may be performed using the
509: .Fl T
510: option.
511: In this mode
512: .Nm
513: will read candidates from standard input (or a file specified using the
514: .Fl f
515: option).
516: For example:
517: .Pp
1.66 jmc 518: .Dl # ssh-keygen -T moduli-2048 -f moduli-2048.candidates
1.60 djm 519: .Pp
520: By default, each candidate will be subjected to 100 primality tests.
521: This may be overridden using the
522: .Fl a
523: option.
524: The DH generator value will be chosen automatically for the
525: prime under consideration.
526: If a specific generator is desired, it may be requested using the
527: .Fl W
528: option.
1.66 jmc 529: Valid generator values are 2, 3, and 5.
1.60 djm 530: .Pp
531: Screened DH groups may be installed in
532: .Pa /etc/moduli .
533: It is important that this file contains moduli of a range of bit lengths and
534: that both ends of a connection share common moduli.
1.84 djm 535: .Sh CERTIFICATES
536: .Nm
537: supports signing of keys to produce certificates that may be used for
538: user or host authentication.
539: Certificates consist of a public key, some identity information, zero or
1.94 jmc 540: more principal (user or host) names and a set of options that
1.84 djm 541: are signed by a Certification Authority (CA) key.
542: Clients or servers may then trust only the CA key and verify its signature
543: on a certificate rather than trusting many user/host keys.
544: Note that OpenSSH certificates are a different, and much simpler, format to
545: the X.509 certificates used in
546: .Xr ssl 8 .
547: .Pp
548: .Nm
549: supports two types of certificates: user and host.
550: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 551: authenticate server hosts to users.
552: To generate a user certificate:
1.84 djm 553: .Pp
554: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
555: .Pp
556: The resultant certificate will be placed in
1.91 djm 557: .Pa /path/to/user_key-cert.pub .
1.84 djm 558: A host certificate requires the
559: .Fl h
560: option:
561: .Pp
562: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
563: .Pp
564: The host certificate will be output to
1.91 djm 565: .Pa /path/to/host_key-cert.pub .
1.98 djm 566: .Pp
567: It is possible to sign using a CA key stored in a PKCS#11 token by
568: providing the token library using
569: .Fl D
570: and identifying the CA key by providing its public half as an argument
571: to
572: .Fl s :
573: .Pp
574: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id host_key.pub
575: .Pp
576: In all cases,
1.84 djm 577: .Ar key_id
578: is a "key identifier" that is logged by the server when the certificate
579: is used for authentication.
580: .Pp
581: Certificates may be limited to be valid for a set of principal (user/host)
582: names.
583: By default, generated certificates are valid for all users or hosts.
584: To generate a certificate for a specified set of principals:
585: .Pp
586: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.92 jmc 587: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub"
1.84 djm 588: .Pp
589: Additional limitations on the validity and use of user certificates may
1.94 jmc 590: be specified through certificate options.
1.93 djm 591: A certificate option may disable features of the SSH session, may be
1.84 djm 592: valid only when presented from particular source addresses or may
593: force the use of a specific command.
1.93 djm 594: For a list of valid certificate options, see the documentation for the
1.84 djm 595: .Fl O
596: option above.
597: .Pp
598: Finally, certificates may be defined with a validity lifetime.
599: The
600: .Fl V
601: option allows specification of certificate start and end times.
602: A certificate that is presented at a time outside this range will not be
603: considered valid.
604: By default, certificates have a maximum validity interval.
605: .Pp
606: For certificates to be used for user or host authentication, the CA
607: public key must be trusted by
608: .Xr sshd 8
609: or
610: .Xr ssh 1 .
611: Please refer to those manual pages for details.
1.2 deraadt 612: .Sh FILES
1.100 naddy 613: .Bl -tag -width Ds -compact
1.68 djm 614: .It Pa ~/.ssh/identity
1.36 itojun 615: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 616: This file should not be readable by anyone but the user.
617: It is possible to
1.1 deraadt 618: specify a passphrase when generating the key; that passphrase will be
1.100 naddy 619: used to encrypt the private part of this file using 3DES.
1.12 aaron 620: This file is not automatically accessed by
1.2 deraadt 621: .Nm
1.1 deraadt 622: but it is offered as the default file for the private key.
1.46 markus 623: .Xr ssh 1
1.15 deraadt 624: will read this file when a login attempt is made.
1.100 naddy 625: .Pp
1.68 djm 626: .It Pa ~/.ssh/identity.pub
1.36 itojun 627: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 628: The contents of this file should be added to
1.68 djm 629: .Pa ~/.ssh/authorized_keys
1.2 deraadt 630: on all machines
1.49 deraadt 631: where the user wishes to log in using RSA authentication.
1.15 deraadt 632: There is no need to keep the contents of this file secret.
1.100 naddy 633: .Pp
1.68 djm 634: .It Pa ~/.ssh/id_dsa
1.100 naddy 635: .It Pa ~/.ssh/id_ecdsa
636: .It Pa ~/.ssh/id_rsa
637: Contains the protocol version 2 DSA, ECDSA or RSA authentication identity of the user.
1.15 deraadt 638: This file should not be readable by anyone but the user.
639: It is possible to
640: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 641: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 642: This file is not automatically accessed by
643: .Nm
644: but it is offered as the default file for the private key.
1.46 markus 645: .Xr ssh 1
1.15 deraadt 646: will read this file when a login attempt is made.
1.100 naddy 647: .Pp
1.68 djm 648: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 649: .It Pa ~/.ssh/id_ecdsa.pub
1.68 djm 650: .It Pa ~/.ssh/id_rsa.pub
1.100 naddy 651: Contains the protocol version 2 DSA, ECDSA or RSA public key for authentication.
1.15 deraadt 652: The contents of this file should be added to
1.68 djm 653: .Pa ~/.ssh/authorized_keys
1.15 deraadt 654: on all machines
1.49 deraadt 655: where the user wishes to log in using public key authentication.
1.12 aaron 656: There is no need to keep the contents of this file secret.
1.100 naddy 657: .Pp
1.60 djm 658: .It Pa /etc/moduli
659: Contains Diffie-Hellman groups used for DH-GEX.
660: The file format is described in
661: .Xr moduli 5 .
1.19 aaron 662: .El
1.2 deraadt 663: .Sh SEE ALSO
664: .Xr ssh 1 ,
665: .Xr ssh-add 1 ,
1.8 ericj 666: .Xr ssh-agent 1 ,
1.60 djm 667: .Xr moduli 5 ,
1.30 itojun 668: .Xr sshd 8
1.37 markus 669: .Rs
1.73 markus 670: .%R RFC 4716
671: .%T "The Secure Shell (SSH) Public Key File Format"
672: .%D 2006
1.37 markus 673: .Re
1.59 jmc 674: .Sh AUTHORS
675: OpenSSH is a derivative of the original and free
676: ssh 1.2.12 release by Tatu Ylonen.
677: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
678: Theo de Raadt and Dug Song
679: removed many bugs, re-added newer features and
680: created OpenSSH.
681: Markus Friedl contributed the support for SSH
682: protocol versions 1.5 and 2.0.
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