Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.101
1.101 ! jmc 1: .\" $OpenBSD: ssh-keygen.1,v 1.100 2010/09/10 15:19:29 naddy 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: .\"
1.101 ! jmc 38: .Dd $Mdocdate: September 10 2010 $
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
1.85 jmc 120: .Ek
1.13 aaron 121: .Sh DESCRIPTION
1.2 deraadt 122: .Nm
1.37 markus 123: generates, manages and converts authentication keys for
1.2 deraadt 124: .Xr ssh 1 .
1.15 deraadt 125: .Nm
1.100 naddy 126: can create RSA keys for use by SSH protocol version 1 and DSA, ECDSA or RSA
1.58 jmc 127: keys for use by SSH protocol version 2.
128: The type of key to be generated is specified with the
1.25 markus 129: .Fl t
1.52 djm 130: option.
1.70 djm 131: If invoked without any arguments,
132: .Nm
1.71 jmc 133: will generate an RSA key for use in SSH protocol 2 connections.
1.15 deraadt 134: .Pp
1.60 djm 135: .Nm
136: is also used to generate groups for use in Diffie-Hellman group
137: exchange (DH-GEX).
138: See the
139: .Sx MODULI GENERATION
140: section for details.
141: .Pp
1.2 deraadt 142: Normally each user wishing to use SSH
1.99 djm 143: with public key authentication runs this once to create the authentication
1.1 deraadt 144: key in
1.68 djm 145: .Pa ~/.ssh/identity ,
1.99 djm 146: .Pa ~/.ssh/id_ecdsa ,
1.68 djm 147: .Pa ~/.ssh/id_dsa
1.15 deraadt 148: or
1.68 djm 149: .Pa ~/.ssh/id_rsa .
1.15 deraadt 150: Additionally, the system administrator may use this to generate host keys,
151: as seen in
152: .Pa /etc/rc .
1.2 deraadt 153: .Pp
1.1 deraadt 154: Normally this program generates the key and asks for a file in which
1.12 aaron 155: to store the private key.
156: The public key is stored in a file with the same name but
1.2 deraadt 157: .Dq .pub
1.12 aaron 158: appended.
159: The program also asks for a passphrase.
160: The passphrase may be empty to indicate no passphrase
1.26 markus 161: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 162: arbitrary length.
1.51 stevesk 163: A passphrase is similar to a password, except it can be a phrase with a
164: series of words, punctuation, numbers, whitespace, or any string of
165: characters you want.
166: Good passphrases are 10-30 characters long, are
1.1 deraadt 167: not simple sentences or otherwise easily guessable (English
1.42 markus 168: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 169: passphrases), and contain a mix of upper and lowercase letters,
170: numbers, and non-alphanumeric characters.
1.12 aaron 171: The passphrase can be changed later by using the
1.2 deraadt 172: .Fl p
1.1 deraadt 173: option.
1.2 deraadt 174: .Pp
1.12 aaron 175: There is no way to recover a lost passphrase.
176: If the passphrase is
1.49 deraadt 177: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 178: corresponding public key to other machines.
1.2 deraadt 179: .Pp
1.37 markus 180: For RSA1 keys,
181: there is also a comment field in the key file that is only for
1.12 aaron 182: convenience to the user to help identify the key.
183: The comment can tell what the key is for, or whatever is useful.
184: The comment is initialized to
1.2 deraadt 185: .Dq user@host
186: when the key is created, but can be changed using the
187: .Fl c
1.1 deraadt 188: option.
1.2 deraadt 189: .Pp
1.15 deraadt 190: After a key is generated, instructions below detail where the keys
191: should be placed to be activated.
192: .Pp
1.2 deraadt 193: The options are as follows:
194: .Bl -tag -width Ds
1.60 djm 195: .It Fl a Ar trials
196: Specifies the number of primality tests to perform when screening DH-GEX
197: candidates using the
198: .Fl T
199: command.
1.66 jmc 200: .It Fl B
201: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 202: .It Fl b Ar bits
1.12 aaron 203: Specifies the number of bits in the key to create.
1.72 dtucker 204: For RSA keys, the minimum size is 768 bits and the default is 2048 bits.
1.69 djm 205: Generally, 2048 bits is considered sufficient.
1.72 dtucker 206: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.66 jmc 207: .It Fl C Ar comment
208: Provides a new comment.
1.2 deraadt 209: .It Fl c
1.1 deraadt 210: Requests changing the comment in the private and public key files.
1.50 markus 211: This operation is only supported for RSA1 keys.
1.1 deraadt 212: The program will prompt for the file containing the private keys, for
1.41 stevesk 213: the passphrase if the key has one, and for the new comment.
1.81 markus 214: .It Fl D Ar pkcs11
1.83 markus 215: Download the RSA public keys provided by the PKCS#11 shared library
216: .Ar pkcs11 .
1.98 djm 217: When used in combination with
218: .Fl s ,
219: this option indicates that a CA key resides in a PKCS#11 token (see the
220: .Sx CERTIFICATES
221: section for details).
1.37 markus 222: .It Fl e
1.40 markus 223: This option will read a private or public OpenSSH key file and
1.95 djm 224: print to stdout the key in one of the formats specified by the
225: .Fl m
226: option.
227: The default export format is
228: .Dq RFC4716 .
1.96 jmc 229: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 230: several commercial SSH implementations.
1.66 jmc 231: .It Fl F Ar hostname
232: Search for the specified
233: .Ar hostname
234: in a
235: .Pa known_hosts
236: file, listing any occurrences found.
237: This option is useful to find hashed host names or addresses and may also be
238: used in conjunction with the
239: .Fl H
240: option to print found keys in a hashed format.
241: .It Fl f Ar filename
242: Specifies the filename of the key file.
243: .It Fl G Ar output_file
244: Generate candidate primes for DH-GEX.
245: These primes must be screened for
246: safety (using the
247: .Fl T
248: option) before use.
1.57 jakob 249: .It Fl g
1.62 jakob 250: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 251: .Fl r
1.62 jakob 252: command.
1.66 jmc 253: .It Fl H
254: Hash a
255: .Pa known_hosts
1.67 dtucker 256: file.
257: This replaces all hostnames and addresses with hashed representations
258: within the specified file; the original content is moved to a file with
259: a .old suffix.
1.66 jmc 260: These hashes may be used normally by
261: .Nm ssh
262: and
263: .Nm sshd ,
264: but they do not reveal identifying information should the file's contents
265: be disclosed.
266: This option will not modify existing hashed hostnames and is therefore safe
267: to use on files that mix hashed and non-hashed names.
1.84 djm 268: .It Fl h
269: When signing a key, create a host certificate instead of a user
270: certificate.
271: Please see the
272: .Sx CERTIFICATES
273: section for details.
1.85 jmc 274: .It Fl I Ar certificate_identity
1.84 djm 275: Specify the key identity when signing a public key.
276: Please see the
277: .Sx CERTIFICATES
278: section for details.
1.37 markus 279: .It Fl i
280: This option will read an unencrypted private (or public) key file
1.95 djm 281: in the format specified by the
282: .Fl m
283: option and print an OpenSSH compatible private
1.37 markus 284: (or public) key to stdout.
1.95 djm 285: This option allows importing keys from other software, including several
286: commercial SSH implementations.
287: The default import format is
288: .Dq RFC4716 .
1.86 djm 289: .It Fl L
290: Prints the contents of a certificate.
1.9 markus 291: .It Fl l
1.77 grunk 292: Show fingerprint of specified public key file.
1.50 markus 293: Private RSA1 keys are also supported.
294: For RSA and DSA keys
295: .Nm
1.78 jmc 296: tries to find the matching public key file and prints its fingerprint.
297: If combined with
298: .Fl v ,
299: an ASCII art representation of the key is supplied with the fingerprint.
1.96 jmc 300: .It Fl M Ar memory
301: Specify the amount of memory to use (in megabytes) when generating
302: candidate moduli for DH-GEX.
1.95 djm 303: .It Fl m Ar key_format
304: Specify a key format for the
305: .Fl i
306: (import) or
307: .Fl e
1.96 jmc 308: (export) conversion options.
1.95 djm 309: The supported key formats are:
310: .Dq RFC4716
1.96 jmc 311: (RFC 4716/SSH2 public or private key),
1.95 djm 312: .Dq PKCS8
313: (PEM PKCS8 public key)
314: or
315: .Dq PEM
316: (PEM public key).
317: The default conversion format is
318: .Dq RFC4716 .
1.66 jmc 319: .It Fl N Ar new_passphrase
320: Provides the new passphrase.
1.84 djm 321: .It Fl n Ar principals
322: Specify one or more principals (user or host names) to be included in
323: a certificate when signing a key.
324: Multiple principals may be specified, separated by commas.
325: Please see the
326: .Sx CERTIFICATES
327: section for details.
1.93 djm 328: .It Fl O Ar option
329: Specify a certificate option when signing a key.
1.84 djm 330: This option may be specified multiple times.
331: Please see the
332: .Sx CERTIFICATES
333: section for details.
1.93 djm 334: The options that are valid for user certificates are:
1.84 djm 335: .Bl -tag -width Ds
1.89 jmc 336: .It Ic clear
337: Clear all enabled permissions.
338: This is useful for clearing the default set of permissions so permissions may
339: be added individually.
340: .It Ic force-command Ns = Ns Ar command
341: Forces the execution of
342: .Ar command
343: instead of any shell or command specified by the user when
344: the certificate is used for authentication.
1.84 djm 345: .It Ic no-agent-forwarding
346: Disable
347: .Xr ssh-agent 1
1.85 jmc 348: forwarding (permitted by default).
1.84 djm 349: .It Ic no-port-forwarding
1.85 jmc 350: Disable port forwarding (permitted by default).
1.84 djm 351: .It Ic no-pty
1.85 jmc 352: Disable PTY allocation (permitted by default).
1.84 djm 353: .It Ic no-user-rc
354: Disable execution of
355: .Pa ~/.ssh/rc
356: by
1.85 jmc 357: .Xr sshd 8
358: (permitted by default).
1.89 jmc 359: .It Ic no-x11-forwarding
360: Disable X11 forwarding (permitted by default).
1.88 djm 361: .It Ic permit-agent-forwarding
362: Allows
363: .Xr ssh-agent 1
364: forwarding.
1.84 djm 365: .It Ic permit-port-forwarding
366: Allows port forwarding.
367: .It Ic permit-pty
368: Allows PTY allocation.
369: .It Ic permit-user-rc
370: Allows execution of
371: .Pa ~/.ssh/rc
372: by
373: .Xr sshd 8 .
1.89 jmc 374: .It Ic permit-x11-forwarding
375: Allows X11 forwarding.
376: .It Ic source-address Ns = Ns Ar address_list
1.90 jmc 377: Restrict the source addresses from which the certificate is considered valid.
1.84 djm 378: The
379: .Ar address_list
380: is a comma-separated list of one or more address/netmask pairs in CIDR
381: format.
382: .El
383: .Pp
1.93 djm 384: At present, no options are valid for host keys.
1.66 jmc 385: .It Fl P Ar passphrase
386: Provides the (old) passphrase.
1.2 deraadt 387: .It Fl p
1.1 deraadt 388: Requests changing the passphrase of a private key file instead of
1.12 aaron 389: creating a new private key.
390: The program will prompt for the file
1.1 deraadt 391: containing the private key, for the old passphrase, and twice for the
392: new passphrase.
1.5 aaron 393: .It Fl q
394: Silence
395: .Nm ssh-keygen .
396: Used by
397: .Pa /etc/rc
398: when creating a new key.
1.64 djm 399: .It Fl R Ar hostname
400: Removes all keys belonging to
401: .Ar hostname
1.65 jmc 402: from a
1.64 djm 403: .Pa known_hosts
404: file.
1.65 jmc 405: This option is useful to delete hashed hosts (see the
1.64 djm 406: .Fl H
407: option above).
1.66 jmc 408: .It Fl r Ar hostname
409: Print the SSHFP fingerprint resource record named
410: .Ar hostname
411: for the specified public key file.
1.60 djm 412: .It Fl S Ar start
413: Specify start point (in hex) when generating candidate moduli for DH-GEX.
1.84 djm 414: .It Fl s Ar ca_key
415: Certify (sign) a public key using the specified CA key.
416: Please see the
417: .Sx CERTIFICATES
418: section for details.
1.60 djm 419: .It Fl T Ar output_file
420: Test DH group exchange candidate primes (generated using the
421: .Fl G
422: option) for safety.
1.66 jmc 423: .It Fl t Ar type
424: Specifies the type of key to create.
425: The possible values are
426: .Dq rsa1
427: for protocol version 1 and
1.100 naddy 428: .Dq dsa ,
429: .Dq ecdsa
430: or
1.66 jmc 431: .Dq rsa
432: for protocol version 2.
1.84 djm 433: .It Fl V Ar validity_interval
434: Specify a validity interval when signing a certificate.
435: A validity interval may consist of a single time, indicating that the
436: certificate is valid beginning now and expiring at that time, or may consist
437: of two times separated by a colon to indicate an explicit time interval.
438: The start time may be specified as a date in YYYYMMDD format, a time
439: in YYYYMMDDHHMMSS format or a relative time (to the current time) consisting
440: of a minus sign followed by a relative time in the format described in the
441: .Sx TIME FORMATS
442: section of
1.90 jmc 443: .Xr sshd_config 5 .
1.84 djm 444: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMMSS time or
445: a relative time starting with a plus character.
446: .Pp
447: For example:
448: .Dq +52w1d
449: (valid from now to 52 weeks and one day from now),
450: .Dq -4w:+4w
451: (valid from four weeks ago to four weeks from now),
452: .Dq 20100101123000:20110101123000
453: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
454: .Dq -1d:20110101
455: (valid from yesterday to midnight, January 1st, 2011).
1.61 djm 456: .It Fl v
457: Verbose mode.
458: Causes
459: .Nm
460: to print debugging messages about its progress.
461: This is helpful for debugging moduli generation.
462: Multiple
463: .Fl v
464: options increase the verbosity.
465: The maximum is 3.
1.66 jmc 466: .It Fl W Ar generator
467: Specify desired generator when testing candidate moduli for DH-GEX.
468: .It Fl y
469: This option will read a private
470: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 471: .It Fl z Ar serial_number
472: Specifies a serial number to be embedded in the certificate to distinguish
473: this certificate from others from the same CA.
474: The default serial number is zero.
1.2 deraadt 475: .El
1.60 djm 476: .Sh MODULI GENERATION
477: .Nm
478: may be used to generate groups for the Diffie-Hellman Group Exchange
479: (DH-GEX) protocol.
480: Generating these groups is a two-step process: first, candidate
481: primes are generated using a fast, but memory intensive process.
482: These candidate primes are then tested for suitability (a CPU-intensive
483: process).
484: .Pp
485: Generation of primes is performed using the
486: .Fl G
487: option.
488: The desired length of the primes may be specified by the
489: .Fl b
490: option.
491: For example:
492: .Pp
1.66 jmc 493: .Dl # ssh-keygen -G moduli-2048.candidates -b 2048
1.60 djm 494: .Pp
495: By default, the search for primes begins at a random point in the
496: desired length range.
497: This may be overridden using the
498: .Fl S
499: option, which specifies a different start point (in hex).
500: .Pp
501: Once a set of candidates have been generated, they must be tested for
502: suitability.
503: This may be performed using the
504: .Fl T
505: option.
506: In this mode
507: .Nm
508: will read candidates from standard input (or a file specified using the
509: .Fl f
510: option).
511: For example:
512: .Pp
1.66 jmc 513: .Dl # ssh-keygen -T moduli-2048 -f moduli-2048.candidates
1.60 djm 514: .Pp
515: By default, each candidate will be subjected to 100 primality tests.
516: This may be overridden using the
517: .Fl a
518: option.
519: The DH generator value will be chosen automatically for the
520: prime under consideration.
521: If a specific generator is desired, it may be requested using the
522: .Fl W
523: option.
1.66 jmc 524: Valid generator values are 2, 3, and 5.
1.60 djm 525: .Pp
526: Screened DH groups may be installed in
527: .Pa /etc/moduli .
528: It is important that this file contains moduli of a range of bit lengths and
529: that both ends of a connection share common moduli.
1.84 djm 530: .Sh CERTIFICATES
531: .Nm
532: supports signing of keys to produce certificates that may be used for
533: user or host authentication.
534: Certificates consist of a public key, some identity information, zero or
1.94 jmc 535: more principal (user or host) names and a set of options that
1.84 djm 536: are signed by a Certification Authority (CA) key.
537: Clients or servers may then trust only the CA key and verify its signature
538: on a certificate rather than trusting many user/host keys.
539: Note that OpenSSH certificates are a different, and much simpler, format to
540: the X.509 certificates used in
541: .Xr ssl 8 .
542: .Pp
543: .Nm
544: supports two types of certificates: user and host.
545: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 546: authenticate server hosts to users.
547: To generate a user certificate:
1.84 djm 548: .Pp
549: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
550: .Pp
551: The resultant certificate will be placed in
1.91 djm 552: .Pa /path/to/user_key-cert.pub .
1.84 djm 553: A host certificate requires the
554: .Fl h
555: option:
556: .Pp
557: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
558: .Pp
559: The host certificate will be output to
1.91 djm 560: .Pa /path/to/host_key-cert.pub .
1.98 djm 561: .Pp
562: It is possible to sign using a CA key stored in a PKCS#11 token by
563: providing the token library using
564: .Fl D
565: and identifying the CA key by providing its public half as an argument
566: to
567: .Fl s :
568: .Pp
569: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id host_key.pub
570: .Pp
571: In all cases,
1.84 djm 572: .Ar key_id
573: is a "key identifier" that is logged by the server when the certificate
574: is used for authentication.
575: .Pp
576: Certificates may be limited to be valid for a set of principal (user/host)
577: names.
578: By default, generated certificates are valid for all users or hosts.
579: To generate a certificate for a specified set of principals:
580: .Pp
581: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.92 jmc 582: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub"
1.84 djm 583: .Pp
584: Additional limitations on the validity and use of user certificates may
1.94 jmc 585: be specified through certificate options.
1.93 djm 586: A certificate option may disable features of the SSH session, may be
1.84 djm 587: valid only when presented from particular source addresses or may
588: force the use of a specific command.
1.93 djm 589: For a list of valid certificate options, see the documentation for the
1.84 djm 590: .Fl O
591: option above.
592: .Pp
593: Finally, certificates may be defined with a validity lifetime.
594: The
595: .Fl V
596: option allows specification of certificate start and end times.
597: A certificate that is presented at a time outside this range will not be
598: considered valid.
599: By default, certificates have a maximum validity interval.
600: .Pp
601: For certificates to be used for user or host authentication, the CA
602: public key must be trusted by
603: .Xr sshd 8
604: or
605: .Xr ssh 1 .
606: Please refer to those manual pages for details.
1.2 deraadt 607: .Sh FILES
1.100 naddy 608: .Bl -tag -width Ds -compact
1.68 djm 609: .It Pa ~/.ssh/identity
1.36 itojun 610: Contains the protocol version 1 RSA authentication identity of the user.
1.12 aaron 611: This file should not be readable by anyone but the user.
612: It is possible to
1.1 deraadt 613: specify a passphrase when generating the key; that passphrase will be
1.100 naddy 614: used to encrypt the private part of this file using 3DES.
1.12 aaron 615: This file is not automatically accessed by
1.2 deraadt 616: .Nm
1.1 deraadt 617: but it is offered as the default file for the private key.
1.46 markus 618: .Xr ssh 1
1.15 deraadt 619: will read this file when a login attempt is made.
1.100 naddy 620: .Pp
1.68 djm 621: .It Pa ~/.ssh/identity.pub
1.36 itojun 622: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 623: The contents of this file should be added to
1.68 djm 624: .Pa ~/.ssh/authorized_keys
1.2 deraadt 625: on all machines
1.49 deraadt 626: where the user wishes to log in using RSA authentication.
1.15 deraadt 627: There is no need to keep the contents of this file secret.
1.100 naddy 628: .Pp
1.68 djm 629: .It Pa ~/.ssh/id_dsa
1.100 naddy 630: .It Pa ~/.ssh/id_ecdsa
631: .It Pa ~/.ssh/id_rsa
632: Contains the protocol version 2 DSA, ECDSA or RSA authentication identity of the user.
1.15 deraadt 633: This file should not be readable by anyone but the user.
634: It is possible to
635: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 636: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 637: This file is not automatically accessed by
638: .Nm
639: but it is offered as the default file for the private key.
1.46 markus 640: .Xr ssh 1
1.15 deraadt 641: will read this file when a login attempt is made.
1.100 naddy 642: .Pp
1.68 djm 643: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 644: .It Pa ~/.ssh/id_ecdsa.pub
1.68 djm 645: .It Pa ~/.ssh/id_rsa.pub
1.100 naddy 646: Contains the protocol version 2 DSA, ECDSA or RSA public key for authentication.
1.15 deraadt 647: The contents of this file should be added to
1.68 djm 648: .Pa ~/.ssh/authorized_keys
1.15 deraadt 649: on all machines
1.49 deraadt 650: where the user wishes to log in using public key authentication.
1.12 aaron 651: There is no need to keep the contents of this file secret.
1.100 naddy 652: .Pp
1.60 djm 653: .It Pa /etc/moduli
654: Contains Diffie-Hellman groups used for DH-GEX.
655: The file format is described in
656: .Xr moduli 5 .
1.19 aaron 657: .El
1.2 deraadt 658: .Sh SEE ALSO
659: .Xr ssh 1 ,
660: .Xr ssh-add 1 ,
1.8 ericj 661: .Xr ssh-agent 1 ,
1.60 djm 662: .Xr moduli 5 ,
1.30 itojun 663: .Xr sshd 8
1.37 markus 664: .Rs
1.73 markus 665: .%R RFC 4716
666: .%T "The Secure Shell (SSH) Public Key File Format"
667: .%D 2006
1.37 markus 668: .Re
1.59 jmc 669: .Sh AUTHORS
670: OpenSSH is a derivative of the original and free
671: ssh 1.2.12 release by Tatu Ylonen.
672: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
673: Theo de Raadt and Dug Song
674: removed many bugs, re-added newer features and
675: created OpenSSH.
676: Markus Friedl contributed the support for SSH
677: protocol versions 1.5 and 2.0.
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