Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.204
1.204 ! dtucker 1: .\" $OpenBSD: ssh-keygen.1,v 1.203 2020/04/03 02:26:56 djm 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: .\"
1.204 ! dtucker 38: .Dd $Mdocdate: April 3 2020 $
1.2 deraadt 39: .Dt SSH-KEYGEN 1
40: .Os
41: .Sh NAME
42: .Nm ssh-keygen
1.179 jmc 43: .Nd OpenSSH authentication key utility
1.2 deraadt 44: .Sh SYNOPSIS
45: .Nm ssh-keygen
1.25 markus 46: .Op Fl q
1.2 deraadt 47: .Op Fl b Ar bits
48: .Op Fl C Ar comment
1.20 markus 49: .Op Fl f Ar output_keyfile
1.155 djm 50: .Op Fl m Ar format
1.175 djm 51: .Op Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
1.171 jmc 52: .Op Fl N Ar new_passphrase
1.191 naddy 53: .Op Fl O Ar option
1.173 naddy 54: .Op Fl w Ar provider
1.2 deraadt 55: .Nm ssh-keygen
56: .Fl p
1.9 markus 57: .Op Fl f Ar keyfile
1.155 djm 58: .Op Fl m Ar format
1.171 jmc 59: .Op Fl N Ar new_passphrase
60: .Op Fl P Ar old_passphrase
1.2 deraadt 61: .Nm ssh-keygen
1.37 markus 62: .Fl i
1.171 jmc 63: .Op Fl f Ar input_keyfile
1.95 djm 64: .Op Fl m Ar key_format
1.16 deraadt 65: .Nm ssh-keygen
1.37 markus 66: .Fl e
1.171 jmc 67: .Op Fl f Ar input_keyfile
1.95 djm 68: .Op Fl m Ar key_format
1.16 deraadt 69: .Nm ssh-keygen
1.17 markus 70: .Fl y
1.20 markus 71: .Op Fl f Ar input_keyfile
1.17 markus 72: .Nm ssh-keygen
1.2 deraadt 73: .Fl c
74: .Op Fl C Ar comment
1.9 markus 75: .Op Fl f Ar keyfile
1.171 jmc 76: .Op Fl P Ar passphrase
1.9 markus 77: .Nm ssh-keygen
78: .Fl l
1.125 naddy 79: .Op Fl v
1.124 djm 80: .Op Fl E Ar fingerprint_hash
1.35 markus 81: .Op Fl f Ar input_keyfile
82: .Nm ssh-keygen
83: .Fl B
1.20 markus 84: .Op Fl f Ar input_keyfile
1.48 jakob 85: .Nm ssh-keygen
1.82 jmc 86: .Fl D Ar pkcs11
1.48 jakob 87: .Nm ssh-keygen
1.64 djm 88: .Fl F Ar hostname
1.170 jmc 89: .Op Fl lv
1.64 djm 90: .Op Fl f Ar known_hosts_file
91: .Nm ssh-keygen
92: .Fl H
93: .Op Fl f Ar known_hosts_file
94: .Nm ssh-keygen
1.187 djm 95: .Fl K
96: .Op Fl w Ar provider
97: .Nm ssh-keygen
1.64 djm 98: .Fl R Ar hostname
99: .Op Fl f Ar known_hosts_file
1.57 jakob 100: .Nm ssh-keygen
101: .Fl r Ar hostname
1.170 jmc 102: .Op Fl g
1.57 jakob 103: .Op Fl f Ar input_keyfile
1.60 djm 104: .Nm ssh-keygen
1.184 djm 105: .Fl M Cm generate
106: .Op Fl O Ar option
1.191 naddy 107: .Ar output_file
1.60 djm 108: .Nm ssh-keygen
1.184 djm 109: .Fl M Cm screen
1.191 naddy 110: .Op Fl f Ar input_file
1.184 djm 111: .Op Fl O Ar option
1.191 naddy 112: .Ar output_file
1.84 djm 113: .Nm ssh-keygen
1.171 jmc 114: .Fl I Ar certificate_identity
1.84 djm 115: .Fl s Ar ca_key
1.170 jmc 116: .Op Fl hU
1.142 djm 117: .Op Fl D Ar pkcs11_provider
1.84 djm 118: .Op Fl n Ar principals
1.93 djm 119: .Op Fl O Ar option
1.84 djm 120: .Op Fl V Ar validity_interval
1.93 djm 121: .Op Fl z Ar serial_number
1.84 djm 122: .Ar
1.86 djm 123: .Nm ssh-keygen
124: .Fl L
125: .Op Fl f Ar input_keyfile
1.102 stevesk 126: .Nm ssh-keygen
127: .Fl A
1.143 djm 128: .Op Fl f Ar prefix_path
1.111 djm 129: .Nm ssh-keygen
130: .Fl k
131: .Fl f Ar krl_file
132: .Op Fl u
1.112 jmc 133: .Op Fl s Ar ca_public
134: .Op Fl z Ar version_number
1.111 djm 135: .Ar
136: .Nm ssh-keygen
137: .Fl Q
1.203 djm 138: .Op Fl l
1.111 djm 139: .Fl f Ar krl_file
140: .Ar
1.163 djm 141: .Nm ssh-keygen
1.196 djm 142: .Fl Y Cm find-principals
1.194 djm 143: .Fl s Ar signature_file
144: .Fl f Ar allowed_signers_file
145: .Nm ssh-keygen
1.171 jmc 146: .Fl Y Cm check-novalidate
147: .Fl n Ar namespace
148: .Fl s Ar signature_file
149: .Nm ssh-keygen
1.163 djm 150: .Fl Y Cm sign
151: .Fl f Ar key_file
152: .Fl n Ar namespace
153: .Ar
154: .Nm ssh-keygen
155: .Fl Y Cm verify
1.171 jmc 156: .Fl f Ar allowed_signers_file
1.163 djm 157: .Fl I Ar signer_identity
158: .Fl n Ar namespace
159: .Fl s Ar signature_file
160: .Op Fl r Ar revocation_file
1.13 aaron 161: .Sh DESCRIPTION
1.2 deraadt 162: .Nm
1.37 markus 163: generates, manages and converts authentication keys for
1.2 deraadt 164: .Xr ssh 1 .
1.15 deraadt 165: .Nm
1.140 jmc 166: can create keys for use by SSH protocol version 2.
1.130 jmc 167: .Pp
1.58 jmc 168: The type of key to be generated is specified with the
1.25 markus 169: .Fl t
1.52 djm 170: option.
1.70 djm 171: If invoked without any arguments,
172: .Nm
1.141 naddy 173: will generate an RSA key.
1.15 deraadt 174: .Pp
1.60 djm 175: .Nm
176: is also used to generate groups for use in Diffie-Hellman group
177: exchange (DH-GEX).
178: See the
179: .Sx MODULI GENERATION
180: section for details.
181: .Pp
1.111 djm 182: Finally,
183: .Nm
184: can be used to generate and update Key Revocation Lists, and to test whether
1.112 jmc 185: given keys have been revoked by one.
186: See the
1.111 djm 187: .Sx KEY REVOCATION LISTS
188: section for details.
189: .Pp
1.2 deraadt 190: Normally each user wishing to use SSH
1.99 djm 191: with public key authentication runs this once to create the authentication
1.1 deraadt 192: key in
1.118 naddy 193: .Pa ~/.ssh/id_dsa ,
1.99 djm 194: .Pa ~/.ssh/id_ecdsa ,
1.173 naddy 195: .Pa ~/.ssh/id_ecdsa_sk ,
1.176 naddy 196: .Pa ~/.ssh/id_ed25519 ,
197: .Pa ~/.ssh/id_ed25519_sk
1.15 deraadt 198: or
1.68 djm 199: .Pa ~/.ssh/id_rsa .
1.15 deraadt 200: Additionally, the system administrator may use this to generate host keys,
201: as seen in
202: .Pa /etc/rc .
1.2 deraadt 203: .Pp
1.1 deraadt 204: Normally this program generates the key and asks for a file in which
1.12 aaron 205: to store the private key.
206: The public key is stored in a file with the same name but
1.2 deraadt 207: .Dq .pub
1.12 aaron 208: appended.
209: The program also asks for a passphrase.
210: The passphrase may be empty to indicate no passphrase
1.26 markus 211: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 212: arbitrary length.
1.51 stevesk 213: A passphrase is similar to a password, except it can be a phrase with a
214: series of words, punctuation, numbers, whitespace, or any string of
215: characters you want.
216: Good passphrases are 10-30 characters long, are
1.1 deraadt 217: not simple sentences or otherwise easily guessable (English
1.42 markus 218: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 219: passphrases), and contain a mix of upper and lowercase letters,
220: numbers, and non-alphanumeric characters.
1.12 aaron 221: The passphrase can be changed later by using the
1.2 deraadt 222: .Fl p
1.1 deraadt 223: option.
1.2 deraadt 224: .Pp
1.12 aaron 225: There is no way to recover a lost passphrase.
1.105 djm 226: If the passphrase is lost or forgotten, a new key must be generated
227: and the corresponding public key copied to other machines.
1.2 deraadt 228: .Pp
1.153 djm 229: .Nm
230: will by default write keys in an OpenSSH-specific format.
231: This format is preferred as it offers better protection for
232: keys at rest as well as allowing storage of key comments within
233: the private key file itself.
234: The key comment may be useful to help identify the key.
1.12 aaron 235: The comment is initialized to
1.2 deraadt 236: .Dq user@host
237: when the key is created, but can be changed using the
238: .Fl c
1.1 deraadt 239: option.
1.153 djm 240: .Pp
241: It is still possible for
242: .Nm
243: to write the previously-used PEM format private keys using the
244: .Fl m
245: flag.
246: This may be used when generating new keys, and existing new-format
247: keys may be converted using this option in conjunction with the
248: .Fl p
249: (change passphrase) flag.
1.2 deraadt 250: .Pp
1.15 deraadt 251: After a key is generated, instructions below detail where the keys
252: should be placed to be activated.
253: .Pp
1.2 deraadt 254: The options are as follows:
255: .Bl -tag -width Ds
1.102 stevesk 256: .It Fl A
1.175 djm 257: For each of the key types (rsa, dsa, ecdsa and ed25519)
1.118 naddy 258: for which host keys
1.102 stevesk 259: do not exist, generate the host keys with the default key file path,
260: an empty passphrase, default bits for the key type, and default comment.
1.144 jmc 261: If
1.143 djm 262: .Fl f
1.144 jmc 263: has also been specified, its argument is used as a prefix to the
1.143 djm 264: default path for the resulting host key files.
1.104 jmc 265: This is used by
1.102 stevesk 266: .Pa /etc/rc
267: to generate new host keys.
1.117 djm 268: .It Fl a Ar rounds
1.169 jmc 269: When saving a private key, this option specifies the number of KDF
1.148 djm 270: (key derivation function) rounds used.
1.117 djm 271: Higher numbers result in slower passphrase verification and increased
272: resistance to brute-force password cracking (should the keys be stolen).
1.204 ! dtucker 273: The default is 16 rounds.
1.66 jmc 274: .It Fl B
275: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 276: .It Fl b Ar bits
1.12 aaron 277: Specifies the number of bits in the key to create.
1.158 dtucker 278: For RSA keys, the minimum size is 1024 bits and the default is 3072 bits.
279: Generally, 3072 bits is considered sufficient.
1.72 dtucker 280: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.106 djm 281: For ECDSA keys, the
282: .Fl b
1.107 deraadt 283: flag determines the key length by selecting from one of three elliptic
1.106 djm 284: curve sizes: 256, 384 or 521 bits.
285: Attempting to use bit lengths other than these three values for ECDSA keys
286: will fail.
1.176 naddy 287: ECDSA-SK, Ed25519 and Ed25519-SK keys have a fixed length and the
1.118 naddy 288: .Fl b
289: flag will be ignored.
1.66 jmc 290: .It Fl C Ar comment
291: Provides a new comment.
1.2 deraadt 292: .It Fl c
1.1 deraadt 293: Requests changing the comment in the private and public key files.
294: The program will prompt for the file containing the private keys, for
1.41 stevesk 295: the passphrase if the key has one, and for the new comment.
1.81 markus 296: .It Fl D Ar pkcs11
1.157 naddy 297: Download the public keys provided by the PKCS#11 shared library
1.83 markus 298: .Ar pkcs11 .
1.98 djm 299: When used in combination with
300: .Fl s ,
301: this option indicates that a CA key resides in a PKCS#11 token (see the
302: .Sx CERTIFICATES
303: section for details).
1.124 djm 304: .It Fl E Ar fingerprint_hash
305: Specifies the hash algorithm used when displaying key fingerprints.
306: Valid options are:
307: .Dq md5
308: and
309: .Dq sha256 .
310: The default is
311: .Dq sha256 .
1.37 markus 312: .It Fl e
1.40 markus 313: This option will read a private or public OpenSSH key file and
1.154 djm 314: print to stdout a public key in one of the formats specified by the
1.95 djm 315: .Fl m
316: option.
317: The default export format is
318: .Dq RFC4716 .
1.96 jmc 319: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 320: several commercial SSH implementations.
1.151 djm 321: .It Fl F Ar hostname | [hostname]:port
1.66 jmc 322: Search for the specified
323: .Ar hostname
1.151 djm 324: (with optional port number)
1.66 jmc 325: in a
326: .Pa known_hosts
327: file, listing any occurrences found.
328: This option is useful to find hashed host names or addresses and may also be
329: used in conjunction with the
330: .Fl H
331: option to print found keys in a hashed format.
332: .It Fl f Ar filename
333: Specifies the filename of the key file.
1.57 jakob 334: .It Fl g
1.62 jakob 335: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 336: .Fl r
1.62 jakob 337: command.
1.66 jmc 338: .It Fl H
339: Hash a
340: .Pa known_hosts
1.67 dtucker 341: file.
342: This replaces all hostnames and addresses with hashed representations
343: within the specified file; the original content is moved to a file with
344: a .old suffix.
1.66 jmc 345: These hashes may be used normally by
346: .Nm ssh
347: and
348: .Nm sshd ,
349: but they do not reveal identifying information should the file's contents
350: be disclosed.
351: This option will not modify existing hashed hostnames and is therefore safe
352: to use on files that mix hashed and non-hashed names.
1.84 djm 353: .It Fl h
354: When signing a key, create a host certificate instead of a user
355: certificate.
356: Please see the
357: .Sx CERTIFICATES
358: section for details.
1.85 jmc 359: .It Fl I Ar certificate_identity
1.84 djm 360: Specify the key identity when signing a public key.
361: Please see the
362: .Sx CERTIFICATES
363: section for details.
1.37 markus 364: .It Fl i
365: This option will read an unencrypted private (or public) key file
1.95 djm 366: in the format specified by the
367: .Fl m
368: option and print an OpenSSH compatible private
1.37 markus 369: (or public) key to stdout.
1.122 jmc 370: This option allows importing keys from other software, including several
371: commercial SSH implementations.
372: The default import format is
373: .Dq RFC4716 .
1.188 jmc 374: .It Fl K
1.187 djm 375: Download resident keys from a FIDO authenticator.
376: Public and private key files will be written to the current directory for
377: each downloaded key.
1.111 djm 378: .It Fl k
379: Generate a KRL file.
380: In this mode,
381: .Nm
382: will generate a KRL file at the location specified via the
383: .Fl f
1.114 jmc 384: flag that revokes every key or certificate presented on the command line.
1.111 djm 385: Keys/certificates to be revoked may be specified by public key file or
386: using the format described in the
387: .Sx KEY REVOCATION LISTS
388: section.
1.86 djm 389: .It Fl L
1.129 djm 390: Prints the contents of one or more certificates.
1.9 markus 391: .It Fl l
1.77 grunk 392: Show fingerprint of specified public key file.
1.50 markus 393: For RSA and DSA keys
394: .Nm
1.78 jmc 395: tries to find the matching public key file and prints its fingerprint.
396: If combined with
397: .Fl v ,
1.132 jmc 398: a visual ASCII art representation of the key is supplied with the
1.131 djm 399: fingerprint.
1.184 djm 400: .It Fl M Cm generate
401: Generate candidate Diffie-Hellman Group Exchange (DH-GEX) parameters for
402: eventual use by the
403: .Sq diffie-hellman-group-exchange-*
404: key exchange methods.
405: The numbers generated by this operation must be further screened before
406: use.
407: See the
408: .Sx MODULI GENERATION
409: section for more information.
410: .It Fl M Cm screen
411: Screen candidate parameters for Diffie-Hellman Group Exchange.
412: This will accept a list of candidate numbers and test that they are
413: safe (Sophie Germain) primes with acceptable group generators.
414: The results of this operation may be added to the
415: .Pa /etc/moduli
416: file.
417: See the
418: .Sx MODULI GENERATION
419: section for more information.
1.95 djm 420: .It Fl m Ar key_format
1.155 djm 421: Specify a key format for key generation, the
1.95 djm 422: .Fl i
1.155 djm 423: (import),
1.95 djm 424: .Fl e
1.155 djm 425: (export) conversion options, and the
426: .Fl p
427: change passphrase operation.
428: The latter may be used to convert between OpenSSH private key and PEM
429: private key formats.
1.95 djm 430: The supported key formats are:
431: .Dq RFC4716
1.96 jmc 432: (RFC 4716/SSH2 public or private key),
1.95 djm 433: .Dq PKCS8
1.161 djm 434: (PKCS8 public or private key)
1.95 djm 435: or
436: .Dq PEM
437: (PEM public key).
1.161 djm 438: By default OpenSSH will write newly-generated private keys in its own
439: format, but when converting public keys for export the default format is
1.95 djm 440: .Dq RFC4716 .
1.148 djm 441: Setting a format of
442: .Dq PEM
443: when generating or updating a supported private key type will cause the
444: key to be stored in the legacy PEM private key format.
1.66 jmc 445: .It Fl N Ar new_passphrase
446: Provides the new passphrase.
1.84 djm 447: .It Fl n Ar principals
448: Specify one or more principals (user or host names) to be included in
449: a certificate when signing a key.
450: Multiple principals may be specified, separated by commas.
451: Please see the
452: .Sx CERTIFICATES
453: section for details.
1.93 djm 454: .It Fl O Ar option
1.184 djm 455: Specify a key/value option.
456: These are specific to the operation that
457: .Nm
458: has been requested to perform.
459: .Pp
460: When signing certificates, one of the options listed in the
1.183 djm 461: .Sx CERTIFICATES
1.184 djm 462: section may be specified here.
463: .Pp
464: When performing moduli generation or screening, one of the options
465: listed in the
466: .Sx MODULI GENERATION
467: section may be specified.
468: .Pp
1.190 jmc 469: When generating a key that will be hosted on a FIDO authenticator,
470: this flag may be used to specify key-specific options.
471: Those supported at present are:
472: .Bl -tag -width Ds
473: .It Cm application
474: Override the default FIDO application/origin string of
1.189 djm 475: .Dq ssh: .
1.190 jmc 476: This may be useful when generating host or domain-specific resident keys.
1.200 djm 477: The specified application string must begin with
478: .Dq ssh: .
1.199 jmc 479: .It Cm challenge Ns = Ns Ar path
1.198 jmc 480: Specifies a path to a challenge string that will be passed to the
481: FIDO token during key generation.
1.199 jmc 482: The challenge string may be used as part of an out-of-band
483: protocol for key enrollment
484: (a random challenge is used by default).
1.190 jmc 485: .It Cm device
486: Explicitly specify a
1.189 djm 487: .Xr fido 4
488: device to use, rather than letting the token middleware select one.
1.190 jmc 489: .It Cm no-touch-required
490: Indicate that the generated private key should not require touch
1.185 djm 491: events (user presence) when making signatures.
492: Note that
493: .Xr sshd 8
494: will refuse such signatures by default, unless overridden via
495: an authorized_keys option.
1.190 jmc 496: .It Cm resident
497: Indicate that the key should be stored on the FIDO authenticator itself.
1.185 djm 498: Resident keys may be supported on FIDO2 tokens and typically require that
499: a PIN be set on the token prior to generation.
500: Resident keys may be loaded off the token using
501: .Xr ssh-add 1 .
1.190 jmc 502: .It Cm user
503: A username to be associated with a resident key,
1.189 djm 504: overriding the empty default username.
505: Specifying a username may be useful when generating multiple resident keys
506: for the same application name.
1.199 jmc 507: .It Cm write-attestation Ns = Ns Ar path
1.197 djm 508: May be used at key generation time to record the attestation certificate
509: returned from FIDO tokens during key generation.
510: By default this information is discarded.
1.190 jmc 511: .El
1.185 djm 512: .Pp
513: The
514: .Fl O
515: option may be specified multiple times.
1.66 jmc 516: .It Fl P Ar passphrase
517: Provides the (old) passphrase.
1.2 deraadt 518: .It Fl p
1.1 deraadt 519: Requests changing the passphrase of a private key file instead of
1.12 aaron 520: creating a new private key.
521: The program will prompt for the file
1.1 deraadt 522: containing the private key, for the old passphrase, and twice for the
523: new passphrase.
1.113 jmc 524: .It Fl Q
525: Test whether keys have been revoked in a KRL.
1.203 djm 526: If the
527: .Fl l
528: option is also specified then the contents of the KRL will be printed.
1.5 aaron 529: .It Fl q
530: Silence
531: .Nm ssh-keygen .
1.152 djm 532: .It Fl R Ar hostname | [hostname]:port
1.151 djm 533: Removes all keys belonging to the specified
1.64 djm 534: .Ar hostname
1.151 djm 535: (with optional port number)
1.65 jmc 536: from a
1.64 djm 537: .Pa known_hosts
538: file.
1.65 jmc 539: This option is useful to delete hashed hosts (see the
1.64 djm 540: .Fl H
541: option above).
1.66 jmc 542: .It Fl r Ar hostname
543: Print the SSHFP fingerprint resource record named
544: .Ar hostname
545: for the specified public key file.
1.84 djm 546: .It Fl s Ar ca_key
547: Certify (sign) a public key using the specified CA key.
548: Please see the
549: .Sx CERTIFICATES
550: section for details.
1.111 djm 551: .Pp
552: When generating a KRL,
553: .Fl s
1.112 jmc 554: specifies a path to a CA public key file used to revoke certificates directly
1.111 djm 555: by key ID or serial number.
556: See the
557: .Sx KEY REVOCATION LISTS
558: section for details.
1.175 djm 559: .It Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
1.66 jmc 560: Specifies the type of key to create.
561: The possible values are
1.100 naddy 562: .Dq dsa ,
1.118 naddy 563: .Dq ecdsa ,
1.173 naddy 564: .Dq ecdsa-sk ,
1.118 naddy 565: .Dq ed25519 ,
1.175 djm 566: .Dq ed25519-sk ,
1.100 naddy 567: or
1.139 jmc 568: .Dq rsa .
1.159 djm 569: .Pp
570: This flag may also be used to specify the desired signature type when
1.160 jmc 571: signing certificates using an RSA CA key.
1.159 djm 572: The available RSA signature variants are
573: .Dq ssh-rsa
574: (SHA1 signatures, not recommended),
1.160 jmc 575: .Dq rsa-sha2-256 ,
576: and
1.159 djm 577: .Dq rsa-sha2-512
578: (the default).
1.142 djm 579: .It Fl U
580: When used in combination with
581: .Fl s ,
582: this option indicates that a CA key resides in a
583: .Xr ssh-agent 1 .
584: See the
585: .Sx CERTIFICATES
586: section for more information.
1.112 jmc 587: .It Fl u
588: Update a KRL.
589: When specified with
590: .Fl k ,
1.114 jmc 591: keys listed via the command line are added to the existing KRL rather than
1.112 jmc 592: a new KRL being created.
1.84 djm 593: .It Fl V Ar validity_interval
594: Specify a validity interval when signing a certificate.
595: A validity interval may consist of a single time, indicating that the
596: certificate is valid beginning now and expiring at that time, or may consist
597: of two times separated by a colon to indicate an explicit time interval.
1.145 djm 598: .Pp
599: The start time may be specified as the string
600: .Dq always
601: to indicate the certificate has no specified start time,
1.147 djm 602: a date in YYYYMMDD format, a time in YYYYMMDDHHMM[SS] format,
1.145 djm 603: a relative time (to the current time) consisting of a minus sign followed by
604: an interval in the format described in the
1.116 jmc 605: TIME FORMATS section of
1.90 jmc 606: .Xr sshd_config 5 .
1.145 djm 607: .Pp
1.147 djm 608: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMM[SS] time,
1.145 djm 609: a relative time starting with a plus character or the string
610: .Dq forever
1.202 dtucker 611: to indicate that the certificate has no expiry date.
1.84 djm 612: .Pp
613: For example:
614: .Dq +52w1d
615: (valid from now to 52 weeks and one day from now),
616: .Dq -4w:+4w
617: (valid from four weeks ago to four weeks from now),
618: .Dq 20100101123000:20110101123000
619: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
620: .Dq -1d:20110101
621: (valid from yesterday to midnight, January 1st, 2011).
1.145 djm 622: .Dq -1m:forever
623: (valid from one minute ago and never expiring).
1.61 djm 624: .It Fl v
625: Verbose mode.
626: Causes
627: .Nm
628: to print debugging messages about its progress.
629: This is helpful for debugging moduli generation.
630: Multiple
631: .Fl v
632: options increase the verbosity.
633: The maximum is 3.
1.173 naddy 634: .It Fl w Ar provider
1.180 naddy 635: Specifies a path to a library that will be used when creating
636: FIDO authenticator-hosted keys, overriding the default of using
637: the internal USB HID support.
1.196 djm 638: .It Fl Y Cm find-principals
639: Find the principal(s) associated with the public key of a signature,
1.194 djm 640: provided using the
641: .Fl s
642: flag in an authorized signers file provided using the
643: .Fl f
644: flag.
645: The format of the allowed signers file is documented in the
646: .Sx ALLOWED SIGNERS
1.195 jmc 647: section below.
1.196 djm 648: If one or more matching principals are found, they are returned on
649: standard output.
1.182 jmc 650: .It Fl Y Cm check-novalidate
651: Checks that a signature generated using
652: .Nm
653: .Fl Y Cm sign
654: has a valid structure.
655: This does not validate if a signature comes from an authorized signer.
656: When testing a signature,
657: .Nm
658: accepts a message on standard input and a signature namespace using
659: .Fl n .
660: A file containing the corresponding signature must also be supplied using the
661: .Fl s
662: flag.
663: Successful testing of the signature is signalled by
664: .Nm
665: returning a zero exit status.
1.166 jmc 666: .It Fl Y Cm sign
1.163 djm 667: Cryptographically sign a file or some data using a SSH key.
668: When signing,
669: .Nm
670: accepts zero or more files to sign on the command-line - if no files
671: are specified then
672: .Nm
673: will sign data presented on standard input.
674: Signatures are written to the path of the input file with
675: .Dq .sig
676: appended, or to standard output if the message to be signed was read from
677: standard input.
678: .Pp
679: The key used for signing is specified using the
680: .Fl f
681: option and may refer to either a private key, or a public key with the private
682: half available via
683: .Xr ssh-agent 1 .
684: An additional signature namespace, used to prevent signature confusion across
685: different domains of use (e.g. file signing vs email signing) must be provided
686: via the
687: .Fl n
688: flag.
689: Namespaces are arbitrary strings, and may include:
690: .Dq file
691: for file signing,
692: .Dq email
693: for email signing.
694: For custom uses, it is recommended to use names following a
695: NAMESPACE@YOUR.DOMAIN pattern to generate unambiguous namespaces.
1.166 jmc 696: .It Fl Y Cm verify
1.163 djm 697: Request to verify a signature generated using
698: .Nm
1.166 jmc 699: .Fl Y Cm sign
1.163 djm 700: as described above.
701: When verifying a signature,
702: .Nm
703: accepts a message on standard input and a signature namespace using
704: .Fl n .
705: A file containing the corresponding signature must also be supplied using the
706: .Fl s
707: flag, along with the identity of the signer using
708: .Fl I
709: and a list of allowed signers via the
710: .Fl f
711: flag.
712: The format of the allowed signers file is documented in the
713: .Sx ALLOWED SIGNERS
714: section below.
715: A file containing revoked keys can be passed using the
716: .Fl r
1.165 jmc 717: flag.
718: The revocation file may be a KRL or a one-per-line list of public keys.
1.163 djm 719: Successful verification by an authorized signer is signalled by
720: .Nm
721: returning a zero exit status.
1.181 jmc 722: .It Fl y
723: This option will read a private
724: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 725: .It Fl z Ar serial_number
726: Specifies a serial number to be embedded in the certificate to distinguish
727: this certificate from others from the same CA.
1.156 djm 728: If the
729: .Ar serial_number
730: is prefixed with a
731: .Sq +
732: character, then the serial number will be incremented for each certificate
733: signed on a single command-line.
1.93 djm 734: The default serial number is zero.
1.111 djm 735: .Pp
736: When generating a KRL, the
737: .Fl z
738: flag is used to specify a KRL version number.
1.2 deraadt 739: .El
1.60 djm 740: .Sh MODULI GENERATION
741: .Nm
742: may be used to generate groups for the Diffie-Hellman Group Exchange
743: (DH-GEX) protocol.
744: Generating these groups is a two-step process: first, candidate
745: primes are generated using a fast, but memory intensive process.
746: These candidate primes are then tested for suitability (a CPU-intensive
747: process).
748: .Pp
749: Generation of primes is performed using the
1.184 djm 750: .Fl M Cm generate
1.60 djm 751: option.
752: The desired length of the primes may be specified by the
1.184 djm 753: .Fl O Cm bits
1.60 djm 754: option.
755: For example:
756: .Pp
1.184 djm 757: .Dl # ssh-keygen -M generate -O bits=2048 moduli-2048.candidates
1.60 djm 758: .Pp
759: By default, the search for primes begins at a random point in the
760: desired length range.
761: This may be overridden using the
1.184 djm 762: .Fl O Cm start
1.60 djm 763: option, which specifies a different start point (in hex).
764: .Pp
1.109 dtucker 765: Once a set of candidates have been generated, they must be screened for
1.60 djm 766: suitability.
767: This may be performed using the
1.184 djm 768: .Fl M Cm screen
1.60 djm 769: option.
770: In this mode
771: .Nm
772: will read candidates from standard input (or a file specified using the
773: .Fl f
774: option).
775: For example:
776: .Pp
1.184 djm 777: .Dl # ssh-keygen -M screen -f moduli-2048.candidates moduli-2048
1.60 djm 778: .Pp
779: By default, each candidate will be subjected to 100 primality tests.
780: This may be overridden using the
1.184 djm 781: .Fl O Cm prime-tests
1.60 djm 782: option.
783: The DH generator value will be chosen automatically for the
784: prime under consideration.
785: If a specific generator is desired, it may be requested using the
1.184 djm 786: .Fl O Cm generator
1.60 djm 787: option.
1.66 jmc 788: Valid generator values are 2, 3, and 5.
1.60 djm 789: .Pp
790: Screened DH groups may be installed in
791: .Pa /etc/moduli .
792: It is important that this file contains moduli of a range of bit lengths and
793: that both ends of a connection share common moduli.
1.184 djm 794: .Pp
795: A number of options are available for moduli generation and screening via the
796: .Fl O
797: flag:
1.186 jmc 798: .Bl -tag -width Ds
1.184 djm 799: .It Ic lines Ns = Ns Ar number
800: Exit after screening the specified number of lines while performing DH
801: candidate screening.
802: .It Ic start-line Ns = Ns Ar line-number
803: Start screening at the specified line number while performing DH candidate
804: screening.
805: .It Ic checkpoint Ns = Ns Ar filename
806: Write the last line processed to the specified file while performing DH
807: candidate screening.
808: This will be used to skip lines in the input file that have already been
809: processed if the job is restarted.
810: .It Ic memory Ns = Ns Ar mbytes
811: Specify the amount of memory to use (in megabytes) when generating
812: candidate moduli for DH-GEX.
813: .It Ic start Ns = Ns Ar hex-value
814: Specify start point (in hex) when generating candidate moduli for DH-GEX.
815: .It Ic generator Ns = Ns Ar value
816: Specify desired generator (in decimal) when testing candidate moduli for DH-GEX.
817: .El
1.84 djm 818: .Sh CERTIFICATES
819: .Nm
820: supports signing of keys to produce certificates that may be used for
821: user or host authentication.
822: Certificates consist of a public key, some identity information, zero or
1.94 jmc 823: more principal (user or host) names and a set of options that
1.84 djm 824: are signed by a Certification Authority (CA) key.
825: Clients or servers may then trust only the CA key and verify its signature
826: on a certificate rather than trusting many user/host keys.
827: Note that OpenSSH certificates are a different, and much simpler, format to
828: the X.509 certificates used in
829: .Xr ssl 8 .
830: .Pp
831: .Nm
832: supports two types of certificates: user and host.
833: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 834: authenticate server hosts to users.
835: To generate a user certificate:
1.84 djm 836: .Pp
837: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
838: .Pp
839: The resultant certificate will be placed in
1.91 djm 840: .Pa /path/to/user_key-cert.pub .
1.84 djm 841: A host certificate requires the
842: .Fl h
843: option:
844: .Pp
845: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
846: .Pp
847: The host certificate will be output to
1.91 djm 848: .Pa /path/to/host_key-cert.pub .
1.98 djm 849: .Pp
850: It is possible to sign using a CA key stored in a PKCS#11 token by
851: providing the token library using
852: .Fl D
853: and identifying the CA key by providing its public half as an argument
854: to
855: .Fl s :
856: .Pp
1.127 naddy 857: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id user_key.pub
1.142 djm 858: .Pp
859: Similarly, it is possible for the CA key to be hosted in a
860: .Xr ssh-agent 1 .
861: This is indicated by the
862: .Fl U
863: flag and, again, the CA key must be identified by its public half.
864: .Pp
865: .Dl $ ssh-keygen -Us ca_key.pub -I key_id user_key.pub
1.98 djm 866: .Pp
867: In all cases,
1.84 djm 868: .Ar key_id
869: is a "key identifier" that is logged by the server when the certificate
870: is used for authentication.
871: .Pp
872: Certificates may be limited to be valid for a set of principal (user/host)
873: names.
874: By default, generated certificates are valid for all users or hosts.
875: To generate a certificate for a specified set of principals:
876: .Pp
877: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.127 naddy 878: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain host_key.pub"
1.84 djm 879: .Pp
880: Additional limitations on the validity and use of user certificates may
1.94 jmc 881: be specified through certificate options.
1.93 djm 882: A certificate option may disable features of the SSH session, may be
1.84 djm 883: valid only when presented from particular source addresses or may
884: force the use of a specific command.
1.183 djm 885: .Pp
886: The options that are valid for user certificates are:
887: .Pp
888: .Bl -tag -width Ds -compact
889: .It Ic clear
890: Clear all enabled permissions.
891: This is useful for clearing the default set of permissions so permissions may
892: be added individually.
893: .Pp
894: .It Ic critical : Ns Ar name Ns Op Ns = Ns Ar contents
895: .It Ic extension : Ns Ar name Ns Op Ns = Ns Ar contents
896: Includes an arbitrary certificate critical option or extension.
897: The specified
898: .Ar name
899: should include a domain suffix, e.g.\&
900: .Dq name@example.com .
901: If
902: .Ar contents
903: is specified then it is included as the contents of the extension/option
904: encoded as a string, otherwise the extension/option is created with no
905: contents (usually indicating a flag).
906: Extensions may be ignored by a client or server that does not recognise them,
907: whereas unknown critical options will cause the certificate to be refused.
908: .Pp
909: .It Ic force-command Ns = Ns Ar command
910: Forces the execution of
911: .Ar command
912: instead of any shell or command specified by the user when
913: the certificate is used for authentication.
914: .Pp
915: .It Ic no-agent-forwarding
916: Disable
917: .Xr ssh-agent 1
918: forwarding (permitted by default).
919: .Pp
920: .It Ic no-port-forwarding
921: Disable port forwarding (permitted by default).
922: .Pp
923: .It Ic no-pty
924: Disable PTY allocation (permitted by default).
925: .Pp
926: .It Ic no-user-rc
927: Disable execution of
928: .Pa ~/.ssh/rc
929: by
930: .Xr sshd 8
931: (permitted by default).
932: .Pp
933: .It Ic no-x11-forwarding
934: Disable X11 forwarding (permitted by default).
935: .Pp
936: .It Ic permit-agent-forwarding
937: Allows
938: .Xr ssh-agent 1
939: forwarding.
940: .Pp
941: .It Ic permit-port-forwarding
942: Allows port forwarding.
943: .Pp
944: .It Ic permit-pty
945: Allows PTY allocation.
946: .Pp
947: .It Ic permit-user-rc
948: Allows execution of
949: .Pa ~/.ssh/rc
950: by
951: .Xr sshd 8 .
952: .Pp
953: .It Ic permit-X11-forwarding
954: Allows X11 forwarding.
955: .Pp
956: .It Ic no-touch-required
957: Do not require signatures made using this key require demonstration
1.193 naddy 958: of user presence (e.g. by having the user touch the authenticator).
1.192 naddy 959: This option only makes sense for the FIDO authenticator algorithms
1.183 djm 960: .Cm ecdsa-sk
961: and
962: .Cm ed25519-sk .
963: .Pp
964: .It Ic source-address Ns = Ns Ar address_list
965: Restrict the source addresses from which the certificate is considered valid.
966: The
967: .Ar address_list
968: is a comma-separated list of one or more address/netmask pairs in CIDR
969: format.
970: .El
971: .Pp
972: At present, no standard options are valid for host keys.
1.84 djm 973: .Pp
974: Finally, certificates may be defined with a validity lifetime.
975: The
976: .Fl V
977: option allows specification of certificate start and end times.
978: A certificate that is presented at a time outside this range will not be
979: considered valid.
1.110 jmc 980: By default, certificates are valid from
981: .Ux
982: Epoch to the distant future.
1.84 djm 983: .Pp
984: For certificates to be used for user or host authentication, the CA
985: public key must be trusted by
986: .Xr sshd 8
987: or
988: .Xr ssh 1 .
989: Please refer to those manual pages for details.
1.111 djm 990: .Sh KEY REVOCATION LISTS
991: .Nm
992: is able to manage OpenSSH format Key Revocation Lists (KRLs).
993: These binary files specify keys or certificates to be revoked using a
1.119 tedu 994: compact format, taking as little as one bit per certificate if they are being
1.111 djm 995: revoked by serial number.
996: .Pp
997: KRLs may be generated using the
998: .Fl k
999: flag.
1.114 jmc 1000: This option reads one or more files from the command line and generates a new
1.111 djm 1001: KRL.
1002: The files may either contain a KRL specification (see below) or public keys,
1003: listed one per line.
1004: Plain public keys are revoked by listing their hash or contents in the KRL and
1005: certificates revoked by serial number or key ID (if the serial is zero or
1006: not available).
1007: .Pp
1008: Revoking keys using a KRL specification offers explicit control over the
1009: types of record used to revoke keys and may be used to directly revoke
1010: certificates by serial number or key ID without having the complete original
1011: certificate on hand.
1012: A KRL specification consists of lines containing one of the following directives
1013: followed by a colon and some directive-specific information.
1014: .Bl -tag -width Ds
1.115 jmc 1015: .It Cm serial : Ar serial_number Ns Op - Ns Ar serial_number
1.111 djm 1016: Revokes a certificate with the specified serial number.
1.112 jmc 1017: Serial numbers are 64-bit values, not including zero and may be expressed
1.111 djm 1018: in decimal, hex or octal.
1019: If two serial numbers are specified separated by a hyphen, then the range
1020: of serial numbers including and between each is revoked.
1021: The CA key must have been specified on the
1022: .Nm
1.114 jmc 1023: command line using the
1.111 djm 1024: .Fl s
1025: option.
1026: .It Cm id : Ar key_id
1027: Revokes a certificate with the specified key ID string.
1028: The CA key must have been specified on the
1029: .Nm
1.114 jmc 1030: command line using the
1.111 djm 1031: .Fl s
1032: option.
1033: .It Cm key : Ar public_key
1034: Revokes the specified key.
1.112 jmc 1035: If a certificate is listed, then it is revoked as a plain public key.
1.111 djm 1036: .It Cm sha1 : Ar public_key
1.149 djm 1037: Revokes the specified key by including its SHA1 hash in the KRL.
1038: .It Cm sha256 : Ar public_key
1039: Revokes the specified key by including its SHA256 hash in the KRL.
1040: KRLs that revoke keys by SHA256 hash are not supported by OpenSSH versions
1041: prior to 7.9.
1042: .It Cm hash : Ar fingerprint
1.150 djm 1043: Revokes a key using a fingerprint hash, as obtained from a
1.149 djm 1044: .Xr sshd 8
1045: authentication log message or the
1046: .Nm
1047: .Fl l
1048: flag.
1049: Only SHA256 fingerprints are supported here and resultant KRLs are
1050: not supported by OpenSSH versions prior to 7.9.
1.111 djm 1051: .El
1052: .Pp
1053: KRLs may be updated using the
1054: .Fl u
1055: flag in addition to
1056: .Fl k .
1.114 jmc 1057: When this option is specified, keys listed via the command line are merged into
1.111 djm 1058: the KRL, adding to those already there.
1059: .Pp
1060: It is also possible, given a KRL, to test whether it revokes a particular key
1061: (or keys).
1062: The
1063: .Fl Q
1.128 jmc 1064: flag will query an existing KRL, testing each key specified on the command line.
1.114 jmc 1065: If any key listed on the command line has been revoked (or an error encountered)
1.111 djm 1066: then
1067: .Nm
1068: will exit with a non-zero exit status.
1069: A zero exit status will only be returned if no key was revoked.
1.163 djm 1070: .Sh ALLOWED SIGNERS
1071: When verifying signatures,
1072: .Nm
1073: uses a simple list of identities and keys to determine whether a signature
1074: comes from an authorized source.
1075: This "allowed signers" file uses a format patterned after the
1076: AUTHORIZED_KEYS FILE FORMAT described in
1.165 jmc 1077: .Xr sshd 8 .
1.163 djm 1078: Each line of the file contains the following space-separated fields:
1079: principals, options, keytype, base64-encoded key.
1080: Empty lines and lines starting with a
1081: .Ql #
1082: are ignored as comments.
1083: .Pp
1084: The principals field is a pattern-list (See PATTERNS in
1085: .Xr ssh_config 5 )
1086: consisting of one or more comma-separated USER@DOMAIN identity patterns
1087: that are accepted for signing.
1088: When verifying, the identity presented via the
1.172 jmc 1089: .Fl I
1090: option must match a principals pattern in order for the corresponding key to be
1.163 djm 1091: considered acceptable for verification.
1092: .Pp
1093: The options (if present) consist of comma-separated option specifications.
1094: No spaces are permitted, except within double quotes.
1095: The following option specifications are supported (note that option keywords
1096: are case-insensitive):
1097: .Bl -tag -width Ds
1098: .It Cm cert-authority
1099: Indicates that this key is accepted as a certificate authority (CA) and
1100: that certificates signed by this CA may be accepted for verification.
1101: .It Cm namespaces="namespace-list"
1102: Specifies a pattern-list of namespaces that are accepted for this key.
1.164 djm 1103: If this option is present, the signature namespace embedded in the
1.163 djm 1104: signature object and presented on the verification command-line must
1105: match the specified list before the key will be considered acceptable.
1106: .El
1107: .Pp
1108: When verifying signatures made by certificates, the expected principal
1109: name must match both the principals pattern in the allowed signers file and
1110: the principals embedded in the certificate itself.
1111: .Pp
1112: An example allowed signers file:
1113: .Bd -literal -offset 3n
1114: # Comments allowed at start of line
1115: user1@example.com,user2@example.com ssh-rsa AAAAX1...
1116: # A certificate authority, trusted for all principals in a domain.
1117: *@example.com cert-authority ssh-ed25519 AAAB4...
1118: # A key that is accepted only for file signing.
1119: user2@example.com namespaces="file" ssh-ed25519 AAA41...
1120: .Ed
1.173 naddy 1121: .Sh ENVIRONMENT
1122: .Bl -tag -width Ds
1123: .It Ev SSH_SK_PROVIDER
1.201 djm 1124: Specifies a path to a library that will be used when loading any
1125: FIDO authenticator-hosted keys, overriding the default of using
1126: the built-in USB HID support.
1.173 naddy 1127: .El
1.2 deraadt 1128: .Sh FILES
1.100 naddy 1129: .Bl -tag -width Ds -compact
1.68 djm 1130: .It Pa ~/.ssh/id_dsa
1.100 naddy 1131: .It Pa ~/.ssh/id_ecdsa
1.173 naddy 1132: .It Pa ~/.ssh/id_ecdsa_sk
1.118 naddy 1133: .It Pa ~/.ssh/id_ed25519
1.176 naddy 1134: .It Pa ~/.ssh/id_ed25519_sk
1.100 naddy 1135: .It Pa ~/.ssh/id_rsa
1.180 naddy 1136: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1137: authenticator-hosted Ed25519 or RSA authentication identity of the user.
1.15 deraadt 1138: This file should not be readable by anyone but the user.
1139: It is possible to
1140: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 1141: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 1142: This file is not automatically accessed by
1143: .Nm
1144: but it is offered as the default file for the private key.
1.46 markus 1145: .Xr ssh 1
1.15 deraadt 1146: will read this file when a login attempt is made.
1.100 naddy 1147: .Pp
1.68 djm 1148: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 1149: .It Pa ~/.ssh/id_ecdsa.pub
1.173 naddy 1150: .It Pa ~/.ssh/id_ecdsa_sk.pub
1.118 naddy 1151: .It Pa ~/.ssh/id_ed25519.pub
1.176 naddy 1152: .It Pa ~/.ssh/id_ed25519_sk.pub
1.68 djm 1153: .It Pa ~/.ssh/id_rsa.pub
1.180 naddy 1154: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1155: authenticator-hosted Ed25519 or RSA public key for authentication.
1.15 deraadt 1156: The contents of this file should be added to
1.68 djm 1157: .Pa ~/.ssh/authorized_keys
1.15 deraadt 1158: on all machines
1.49 deraadt 1159: where the user wishes to log in using public key authentication.
1.12 aaron 1160: There is no need to keep the contents of this file secret.
1.100 naddy 1161: .Pp
1.60 djm 1162: .It Pa /etc/moduli
1163: Contains Diffie-Hellman groups used for DH-GEX.
1164: The file format is described in
1165: .Xr moduli 5 .
1.19 aaron 1166: .El
1.2 deraadt 1167: .Sh SEE ALSO
1168: .Xr ssh 1 ,
1169: .Xr ssh-add 1 ,
1.8 ericj 1170: .Xr ssh-agent 1 ,
1.60 djm 1171: .Xr moduli 5 ,
1.30 itojun 1172: .Xr sshd 8
1.37 markus 1173: .Rs
1.73 markus 1174: .%R RFC 4716
1175: .%T "The Secure Shell (SSH) Public Key File Format"
1176: .%D 2006
1.37 markus 1177: .Re
1.59 jmc 1178: .Sh AUTHORS
1179: OpenSSH is a derivative of the original and free
1180: ssh 1.2.12 release by Tatu Ylonen.
1181: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
1182: Theo de Raadt and Dug Song
1183: removed many bugs, re-added newer features and
1184: created OpenSSH.
1185: Markus Friedl contributed the support for SSH
1186: protocol versions 1.5 and 2.0.
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