Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.98
1.98 ! djm 1: .\" $OpenBSD: ssh-keygen.1,v 1.97 2010/07/15 21:20:38 schwarze 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.
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1.1 deraadt 39: .\"
1.98 ! djm 40: .Dd $Mdocdate: July 15 2010 $
1.2 deraadt 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
1.97 schwarze 47: .Bk -words
1.2 deraadt 48: .Nm ssh-keygen
1.25 markus 49: .Op Fl q
1.2 deraadt 50: .Op Fl b Ar bits
1.53 stevesk 51: .Fl t Ar type
1.2 deraadt 52: .Op Fl N Ar new_passphrase
53: .Op Fl C Ar comment
1.20 markus 54: .Op Fl f Ar output_keyfile
1.2 deraadt 55: .Nm ssh-keygen
56: .Fl p
57: .Op Fl P Ar old_passphrase
58: .Op Fl N Ar new_passphrase
1.9 markus 59: .Op Fl f Ar keyfile
1.2 deraadt 60: .Nm ssh-keygen
1.37 markus 61: .Fl i
1.95 djm 62: .Op Fl m Ar key_format
1.20 markus 63: .Op Fl f Ar input_keyfile
1.16 deraadt 64: .Nm ssh-keygen
1.37 markus 65: .Fl e
1.95 djm 66: .Op Fl m Ar key_format
1.20 markus 67: .Op Fl f Ar input_keyfile
1.16 deraadt 68: .Nm ssh-keygen
1.17 markus 69: .Fl y
1.20 markus 70: .Op Fl f Ar input_keyfile
1.17 markus 71: .Nm ssh-keygen
1.2 deraadt 72: .Fl c
73: .Op Fl P Ar passphrase
74: .Op Fl C Ar comment
1.9 markus 75: .Op Fl f Ar keyfile
76: .Nm ssh-keygen
77: .Fl l
1.35 markus 78: .Op Fl f Ar input_keyfile
79: .Nm ssh-keygen
80: .Fl B
1.20 markus 81: .Op Fl f Ar input_keyfile
1.48 jakob 82: .Nm ssh-keygen
1.82 jmc 83: .Fl D Ar pkcs11
1.48 jakob 84: .Nm ssh-keygen
1.64 djm 85: .Fl F Ar hostname
86: .Op Fl f Ar known_hosts_file
1.79 sthen 87: .Op Fl l
1.64 djm 88: .Nm ssh-keygen
89: .Fl H
90: .Op Fl f Ar known_hosts_file
91: .Nm ssh-keygen
92: .Fl R Ar hostname
93: .Op Fl f Ar known_hosts_file
1.57 jakob 94: .Nm ssh-keygen
95: .Fl r Ar hostname
96: .Op Fl f Ar input_keyfile
97: .Op Fl g
1.60 djm 98: .Nm ssh-keygen
99: .Fl G Ar output_file
1.61 djm 100: .Op Fl v
1.60 djm 101: .Op Fl b Ar bits
102: .Op Fl M Ar memory
103: .Op Fl S Ar start_point
104: .Nm ssh-keygen
105: .Fl T Ar output_file
106: .Fl f Ar input_file
1.61 djm 107: .Op Fl v
1.60 djm 108: .Op Fl a Ar num_trials
109: .Op Fl W Ar generator
1.84 djm 110: .Nm ssh-keygen
111: .Fl s Ar ca_key
112: .Fl I Ar certificate_identity
113: .Op Fl h
114: .Op Fl n Ar principals
1.93 djm 115: .Op Fl O Ar option
1.84 djm 116: .Op Fl V Ar validity_interval
1.93 djm 117: .Op Fl z Ar serial_number
1.84 djm 118: .Ar
1.86 djm 119: .Nm ssh-keygen
120: .Fl L
121: .Op Fl f Ar input_keyfile
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
1.54 deraadt 128: can create RSA keys for use by SSH protocol version 1 and RSA or DSA
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
1.15 deraadt 145: with RSA or DSA authentication runs this once to create the authentication
1.1 deraadt 146: key in
1.68 djm 147: .Pa ~/.ssh/identity ,
148: .Pa ~/.ssh/id_dsa
1.15 deraadt 149: or
1.68 djm 150: .Pa ~/.ssh/id_rsa .
1.15 deraadt 151: Additionally, the system administrator may use this to generate host keys,
152: as seen in
153: .Pa /etc/rc .
1.2 deraadt 154: .Pp
1.1 deraadt 155: Normally this program generates the key and asks for a file in which
1.12 aaron 156: to store the private key.
157: The public key is stored in a file with the same name but
1.2 deraadt 158: .Dq .pub
1.12 aaron 159: appended.
160: The program also asks for a passphrase.
161: The passphrase may be empty to indicate no passphrase
1.26 markus 162: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 163: arbitrary length.
1.51 stevesk 164: A passphrase is similar to a password, except it can be a phrase with a
165: series of words, punctuation, numbers, whitespace, or any string of
166: characters you want.
167: Good passphrases are 10-30 characters long, are
1.1 deraadt 168: not simple sentences or otherwise easily guessable (English
1.42 markus 169: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 170: passphrases), and contain a mix of upper and lowercase letters,
171: numbers, and non-alphanumeric characters.
1.12 aaron 172: The passphrase can be changed later by using the
1.2 deraadt 173: .Fl p
1.1 deraadt 174: option.
1.2 deraadt 175: .Pp
1.12 aaron 176: There is no way to recover a lost passphrase.
177: If the passphrase is
1.49 deraadt 178: lost or forgotten, a new key must be generated and copied to the
1.1 deraadt 179: corresponding public key 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
1.60 djm 196: .It Fl a Ar trials
197: Specifies the number of primality tests to perform when screening DH-GEX
198: candidates using the
199: .Fl T
200: command.
1.66 jmc 201: .It Fl B
202: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 203: .It Fl b Ar bits
1.12 aaron 204: Specifies the number of bits in the key to create.
1.72 dtucker 205: For RSA keys, the minimum size is 768 bits and the default is 2048 bits.
1.69 djm 206: Generally, 2048 bits is considered sufficient.
1.72 dtucker 207: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.66 jmc 208: .It Fl C Ar comment
209: Provides a new comment.
1.2 deraadt 210: .It Fl c
1.1 deraadt 211: Requests changing the comment in the private and public key files.
1.50 markus 212: This operation is only supported for RSA1 keys.
1.1 deraadt 213: The program will prompt for the file containing the private keys, for
1.41 stevesk 214: the passphrase if the key has one, and for the new comment.
1.81 markus 215: .It Fl D Ar pkcs11
1.83 markus 216: Download the RSA public keys provided by the PKCS#11 shared library
217: .Ar pkcs11 .
1.98 ! djm 218: When used in combination with
! 219: .Fl s ,
! 220: this option indicates that a CA key resides in a PKCS#11 token (see the
! 221: .Sx CERTIFICATES
! 222: section for details).
1.37 markus 223: .It Fl e
1.40 markus 224: This option will read a private or public OpenSSH key file and
1.95 djm 225: print to stdout the key in one of the formats specified by the
226: .Fl m
227: option.
228: The default export format is
229: .Dq RFC4716 .
1.96 jmc 230: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 231: several commercial SSH implementations.
1.66 jmc 232: .It Fl F Ar hostname
233: Search for the specified
234: .Ar hostname
235: in a
236: .Pa known_hosts
237: file, listing any occurrences found.
238: This option is useful to find hashed host names or addresses and may also be
239: used in conjunction with the
240: .Fl H
241: option to print found keys in a hashed format.
242: .It Fl f Ar filename
243: Specifies the filename of the key file.
244: .It Fl G Ar output_file
245: Generate candidate primes for DH-GEX.
246: These primes must be screened for
247: safety (using the
248: .Fl T
249: option) before use.
1.57 jakob 250: .It Fl g
1.62 jakob 251: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 252: .Fl r
1.62 jakob 253: command.
1.66 jmc 254: .It Fl H
255: Hash a
256: .Pa known_hosts
1.67 dtucker 257: file.
258: This replaces all hostnames and addresses with hashed representations
259: within the specified file; the original content is moved to a file with
260: a .old suffix.
1.66 jmc 261: These hashes may be used normally by
262: .Nm ssh
263: and
264: .Nm sshd ,
265: but they do not reveal identifying information should the file's contents
266: be disclosed.
267: This option will not modify existing hashed hostnames and is therefore safe
268: to use on files that mix hashed and non-hashed names.
1.84 djm 269: .It Fl h
270: When signing a key, create a host certificate instead of a user
271: certificate.
272: Please see the
273: .Sx CERTIFICATES
274: section for details.
1.85 jmc 275: .It Fl I Ar certificate_identity
1.84 djm 276: Specify the key identity when signing a public key.
277: Please see the
278: .Sx CERTIFICATES
279: section for details.
1.37 markus 280: .It Fl i
281: This option will read an unencrypted private (or public) key file
1.95 djm 282: in the format specified by the
283: .Fl m
284: option and print an OpenSSH compatible private
1.37 markus 285: (or public) key to stdout.
1.95 djm 286: This option allows importing keys from other software, including several
287: commercial SSH implementations.
288: The default import format is
289: .Dq RFC4716 .
1.86 djm 290: .It Fl L
291: Prints the contents of a certificate.
1.9 markus 292: .It Fl l
1.77 grunk 293: Show fingerprint of specified public key file.
1.50 markus 294: Private RSA1 keys are also supported.
295: For RSA and DSA keys
296: .Nm
1.78 jmc 297: tries to find the matching public key file and prints its fingerprint.
298: If combined with
299: .Fl v ,
300: an ASCII art representation of the key is supplied with the fingerprint.
1.96 jmc 301: .It Fl M Ar memory
302: Specify the amount of memory to use (in megabytes) when generating
303: candidate moduli for DH-GEX.
1.95 djm 304: .It Fl m Ar key_format
305: Specify a key format for the
306: .Fl i
307: (import) or
308: .Fl e
1.96 jmc 309: (export) conversion options.
1.95 djm 310: The supported key formats are:
311: .Dq RFC4716
1.96 jmc 312: (RFC 4716/SSH2 public or private key),
1.95 djm 313: .Dq PKCS8
314: (PEM PKCS8 public key)
315: or
316: .Dq PEM
317: (PEM public key).
318: The default conversion format is
319: .Dq RFC4716 .
1.66 jmc 320: .It Fl N Ar new_passphrase
321: Provides the new passphrase.
1.84 djm 322: .It Fl n Ar principals
323: Specify one or more principals (user or host names) to be included in
324: a certificate when signing a key.
325: Multiple principals may be specified, separated by commas.
326: Please see the
327: .Sx CERTIFICATES
328: section for details.
1.93 djm 329: .It Fl O Ar option
330: Specify a certificate option when signing a key.
1.84 djm 331: This option may be specified multiple times.
332: Please see the
333: .Sx CERTIFICATES
334: section for details.
1.93 djm 335: The options that are valid for user certificates are:
1.84 djm 336: .Bl -tag -width Ds
1.89 jmc 337: .It Ic clear
338: Clear all enabled permissions.
339: This is useful for clearing the default set of permissions so permissions may
340: be added individually.
341: .It Ic force-command Ns = Ns Ar command
342: Forces the execution of
343: .Ar command
344: instead of any shell or command specified by the user when
345: the certificate is used for authentication.
1.84 djm 346: .It Ic no-agent-forwarding
347: Disable
348: .Xr ssh-agent 1
1.85 jmc 349: forwarding (permitted by default).
1.84 djm 350: .It Ic no-port-forwarding
1.85 jmc 351: Disable port forwarding (permitted by default).
1.84 djm 352: .It Ic no-pty
1.85 jmc 353: Disable PTY allocation (permitted by default).
1.84 djm 354: .It Ic no-user-rc
355: Disable execution of
356: .Pa ~/.ssh/rc
357: by
1.85 jmc 358: .Xr sshd 8
359: (permitted by default).
1.89 jmc 360: .It Ic no-x11-forwarding
361: Disable X11 forwarding (permitted by default).
1.88 djm 362: .It Ic permit-agent-forwarding
363: Allows
364: .Xr ssh-agent 1
365: forwarding.
1.84 djm 366: .It Ic permit-port-forwarding
367: Allows port forwarding.
368: .It Ic permit-pty
369: Allows PTY allocation.
370: .It Ic permit-user-rc
371: Allows execution of
372: .Pa ~/.ssh/rc
373: by
374: .Xr sshd 8 .
1.89 jmc 375: .It Ic permit-x11-forwarding
376: Allows X11 forwarding.
377: .It Ic source-address Ns = Ns Ar address_list
1.90 jmc 378: Restrict the source addresses from which the certificate is considered valid.
1.84 djm 379: The
380: .Ar address_list
381: is a comma-separated list of one or more address/netmask pairs in CIDR
382: format.
383: .El
384: .Pp
1.93 djm 385: At present, no options are valid for host keys.
1.66 jmc 386: .It Fl P Ar passphrase
387: Provides the (old) passphrase.
1.2 deraadt 388: .It Fl p
1.1 deraadt 389: Requests changing the passphrase of a private key file instead of
1.12 aaron 390: creating a new private key.
391: The program will prompt for the file
1.1 deraadt 392: containing the private key, for the old passphrase, and twice for the
393: new passphrase.
1.5 aaron 394: .It Fl q
395: Silence
396: .Nm ssh-keygen .
397: Used by
398: .Pa /etc/rc
399: when creating a new key.
1.64 djm 400: .It Fl R Ar hostname
401: Removes all keys belonging to
402: .Ar hostname
1.65 jmc 403: from a
1.64 djm 404: .Pa known_hosts
405: file.
1.65 jmc 406: This option is useful to delete hashed hosts (see the
1.64 djm 407: .Fl H
408: option above).
1.66 jmc 409: .It Fl r Ar hostname
410: Print the SSHFP fingerprint resource record named
411: .Ar hostname
412: for the specified public key file.
1.60 djm 413: .It Fl S Ar start
414: Specify start point (in hex) when generating candidate moduli for DH-GEX.
1.84 djm 415: .It Fl s Ar ca_key
416: Certify (sign) a public key using the specified CA key.
417: Please see the
418: .Sx CERTIFICATES
419: section for details.
1.60 djm 420: .It Fl T Ar output_file
421: Test DH group exchange candidate primes (generated using the
422: .Fl G
423: option) for safety.
1.66 jmc 424: .It Fl t Ar type
425: Specifies the type of key to create.
426: The possible values are
427: .Dq rsa1
428: for protocol version 1 and
429: .Dq rsa
430: or
431: .Dq dsa
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
608: .Bl -tag -width Ds
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
1.80 dtucker 614: used to encrypt the private part of this file using 128-bit AES.
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.
1.68 djm 620: .It Pa ~/.ssh/identity.pub
1.36 itojun 621: Contains the protocol version 1 RSA public key for authentication.
1.12 aaron 622: The contents of this file should be added to
1.68 djm 623: .Pa ~/.ssh/authorized_keys
1.2 deraadt 624: on all machines
1.49 deraadt 625: where the user wishes to log in using RSA authentication.
1.15 deraadt 626: There is no need to keep the contents of this file secret.
1.68 djm 627: .It Pa ~/.ssh/id_dsa
1.36 itojun 628: Contains the protocol version 2 DSA authentication identity of the user.
1.15 deraadt 629: This file should not be readable by anyone but the user.
630: It is possible to
631: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 632: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 633: This file is not automatically accessed by
634: .Nm
635: but it is offered as the default file for the private key.
1.46 markus 636: .Xr ssh 1
1.15 deraadt 637: will read this file when a login attempt is made.
1.68 djm 638: .It Pa ~/.ssh/id_dsa.pub
1.36 itojun 639: Contains the protocol version 2 DSA public key for authentication.
640: The contents of this file should be added to
1.68 djm 641: .Pa ~/.ssh/authorized_keys
1.36 itojun 642: on all machines
1.49 deraadt 643: where the user wishes to log in using public key authentication.
1.36 itojun 644: There is no need to keep the contents of this file secret.
1.68 djm 645: .It Pa ~/.ssh/id_rsa
1.36 itojun 646: Contains the protocol version 2 RSA authentication identity of the user.
647: This file should not be readable by anyone but the user.
648: It is possible to
649: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 650: used to encrypt the private part of this file using 128-bit AES.
1.36 itojun 651: This file is not automatically accessed by
652: .Nm
653: but it is offered as the default file for the private key.
1.46 markus 654: .Xr ssh 1
1.36 itojun 655: will read this file when a login attempt is made.
1.68 djm 656: .It Pa ~/.ssh/id_rsa.pub
1.36 itojun 657: Contains the protocol version 2 RSA public key for authentication.
1.15 deraadt 658: The contents of this file should be added to
1.68 djm 659: .Pa ~/.ssh/authorized_keys
1.15 deraadt 660: on all machines
1.49 deraadt 661: where the user wishes to log in using public key authentication.
1.12 aaron 662: There is no need to keep the contents of this file secret.
1.60 djm 663: .It Pa /etc/moduli
664: Contains Diffie-Hellman groups used for DH-GEX.
665: The file format is described in
666: .Xr moduli 5 .
1.19 aaron 667: .El
1.2 deraadt 668: .Sh SEE ALSO
669: .Xr ssh 1 ,
670: .Xr ssh-add 1 ,
1.8 ericj 671: .Xr ssh-agent 1 ,
1.60 djm 672: .Xr moduli 5 ,
1.30 itojun 673: .Xr sshd 8
1.37 markus 674: .Rs
1.73 markus 675: .%R RFC 4716
676: .%T "The Secure Shell (SSH) Public Key File Format"
677: .%D 2006
1.37 markus 678: .Re
1.59 jmc 679: .Sh AUTHORS
680: OpenSSH is a derivative of the original and free
681: ssh 1.2.12 release by Tatu Ylonen.
682: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
683: Theo de Raadt and Dug Song
684: removed many bugs, re-added newer features and
685: created OpenSSH.
686: Markus Friedl contributed the support for SSH
687: protocol versions 1.5 and 2.0.
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