Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.205
1.205 ! solene 1: .\" $OpenBSD: ssh-keygen.1,v 1.204 2020/07/15 04:27:34 dtucker 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
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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: .\"
1.205 ! solene 38: .Dd $Mdocdate: July 15 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
1.205 ! solene 47: .Op Fl a Ar rounds
1.2 deraadt 48: .Op Fl b Ar bits
49: .Op Fl C Ar comment
1.20 markus 50: .Op Fl f Ar output_keyfile
1.155 djm 51: .Op Fl m Ar format
1.171 jmc 52: .Op Fl N Ar new_passphrase
1.191 naddy 53: .Op Fl O Ar option
1.205 ! solene 54: .Op Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
1.173 naddy 55: .Op Fl w Ar provider
1.2 deraadt 56: .Nm ssh-keygen
57: .Fl p
1.205 ! solene 58: .Op Fl a Ar rounds
1.9 markus 59: .Op Fl f Ar keyfile
1.155 djm 60: .Op Fl m Ar format
1.171 jmc 61: .Op Fl N Ar new_passphrase
62: .Op Fl P Ar old_passphrase
1.2 deraadt 63: .Nm ssh-keygen
1.37 markus 64: .Fl i
1.171 jmc 65: .Op Fl f Ar input_keyfile
1.95 djm 66: .Op Fl m Ar key_format
1.16 deraadt 67: .Nm ssh-keygen
1.37 markus 68: .Fl e
1.171 jmc 69: .Op Fl f Ar input_keyfile
1.95 djm 70: .Op Fl m Ar key_format
1.16 deraadt 71: .Nm ssh-keygen
1.17 markus 72: .Fl y
1.20 markus 73: .Op Fl f Ar input_keyfile
1.17 markus 74: .Nm ssh-keygen
1.2 deraadt 75: .Fl c
1.205 ! solene 76: .Op Fl a Ar rounds
1.2 deraadt 77: .Op Fl C Ar comment
1.9 markus 78: .Op Fl f Ar keyfile
1.171 jmc 79: .Op Fl P Ar passphrase
1.9 markus 80: .Nm ssh-keygen
81: .Fl l
1.125 naddy 82: .Op Fl v
1.124 djm 83: .Op Fl E Ar fingerprint_hash
1.35 markus 84: .Op Fl f Ar input_keyfile
85: .Nm ssh-keygen
86: .Fl B
1.20 markus 87: .Op Fl f Ar input_keyfile
1.48 jakob 88: .Nm ssh-keygen
1.82 jmc 89: .Fl D Ar pkcs11
1.48 jakob 90: .Nm ssh-keygen
1.64 djm 91: .Fl F Ar hostname
1.170 jmc 92: .Op Fl lv
1.64 djm 93: .Op Fl f Ar known_hosts_file
94: .Nm ssh-keygen
95: .Fl H
96: .Op Fl f Ar known_hosts_file
97: .Nm ssh-keygen
1.187 djm 98: .Fl K
1.205 ! solene 99: .Op Fl a Ar rounds
1.187 djm 100: .Op Fl w Ar provider
101: .Nm ssh-keygen
1.64 djm 102: .Fl R Ar hostname
103: .Op Fl f Ar known_hosts_file
1.57 jakob 104: .Nm ssh-keygen
105: .Fl r Ar hostname
1.170 jmc 106: .Op Fl g
1.57 jakob 107: .Op Fl f Ar input_keyfile
1.60 djm 108: .Nm ssh-keygen
1.184 djm 109: .Fl M Cm generate
110: .Op Fl O Ar option
1.191 naddy 111: .Ar output_file
1.60 djm 112: .Nm ssh-keygen
1.184 djm 113: .Fl M Cm screen
1.191 naddy 114: .Op Fl f Ar input_file
1.184 djm 115: .Op Fl O Ar option
1.191 naddy 116: .Ar output_file
1.84 djm 117: .Nm ssh-keygen
1.171 jmc 118: .Fl I Ar certificate_identity
1.84 djm 119: .Fl s Ar ca_key
1.170 jmc 120: .Op Fl hU
1.142 djm 121: .Op Fl D Ar pkcs11_provider
1.84 djm 122: .Op Fl n Ar principals
1.93 djm 123: .Op Fl O Ar option
1.84 djm 124: .Op Fl V Ar validity_interval
1.93 djm 125: .Op Fl z Ar serial_number
1.84 djm 126: .Ar
1.86 djm 127: .Nm ssh-keygen
128: .Fl L
129: .Op Fl f Ar input_keyfile
1.102 stevesk 130: .Nm ssh-keygen
131: .Fl A
1.205 ! solene 132: .Op Fl a Ar rounds
1.143 djm 133: .Op Fl f Ar prefix_path
1.111 djm 134: .Nm ssh-keygen
135: .Fl k
136: .Fl f Ar krl_file
137: .Op Fl u
1.112 jmc 138: .Op Fl s Ar ca_public
139: .Op Fl z Ar version_number
1.111 djm 140: .Ar
141: .Nm ssh-keygen
142: .Fl Q
1.203 djm 143: .Op Fl l
1.111 djm 144: .Fl f Ar krl_file
145: .Ar
1.163 djm 146: .Nm ssh-keygen
1.196 djm 147: .Fl Y Cm find-principals
1.194 djm 148: .Fl s Ar signature_file
149: .Fl f Ar allowed_signers_file
150: .Nm ssh-keygen
1.171 jmc 151: .Fl Y Cm check-novalidate
152: .Fl n Ar namespace
153: .Fl s Ar signature_file
154: .Nm ssh-keygen
1.163 djm 155: .Fl Y Cm sign
156: .Fl f Ar key_file
157: .Fl n Ar namespace
158: .Ar
159: .Nm ssh-keygen
160: .Fl Y Cm verify
1.171 jmc 161: .Fl f Ar allowed_signers_file
1.163 djm 162: .Fl I Ar signer_identity
163: .Fl n Ar namespace
164: .Fl s Ar signature_file
165: .Op Fl r Ar revocation_file
1.13 aaron 166: .Sh DESCRIPTION
1.2 deraadt 167: .Nm
1.37 markus 168: generates, manages and converts authentication keys for
1.2 deraadt 169: .Xr ssh 1 .
1.15 deraadt 170: .Nm
1.140 jmc 171: can create keys for use by SSH protocol version 2.
1.130 jmc 172: .Pp
1.58 jmc 173: The type of key to be generated is specified with the
1.25 markus 174: .Fl t
1.52 djm 175: option.
1.70 djm 176: If invoked without any arguments,
177: .Nm
1.141 naddy 178: will generate an RSA key.
1.15 deraadt 179: .Pp
1.60 djm 180: .Nm
181: is also used to generate groups for use in Diffie-Hellman group
182: exchange (DH-GEX).
183: See the
184: .Sx MODULI GENERATION
185: section for details.
186: .Pp
1.111 djm 187: Finally,
188: .Nm
189: can be used to generate and update Key Revocation Lists, and to test whether
1.112 jmc 190: given keys have been revoked by one.
191: See the
1.111 djm 192: .Sx KEY REVOCATION LISTS
193: section for details.
194: .Pp
1.2 deraadt 195: Normally each user wishing to use SSH
1.99 djm 196: with public key authentication runs this once to create the authentication
1.1 deraadt 197: key in
1.118 naddy 198: .Pa ~/.ssh/id_dsa ,
1.99 djm 199: .Pa ~/.ssh/id_ecdsa ,
1.173 naddy 200: .Pa ~/.ssh/id_ecdsa_sk ,
1.176 naddy 201: .Pa ~/.ssh/id_ed25519 ,
202: .Pa ~/.ssh/id_ed25519_sk
1.15 deraadt 203: or
1.68 djm 204: .Pa ~/.ssh/id_rsa .
1.15 deraadt 205: Additionally, the system administrator may use this to generate host keys,
206: as seen in
207: .Pa /etc/rc .
1.2 deraadt 208: .Pp
1.1 deraadt 209: Normally this program generates the key and asks for a file in which
1.12 aaron 210: to store the private key.
211: The public key is stored in a file with the same name but
1.2 deraadt 212: .Dq .pub
1.12 aaron 213: appended.
214: The program also asks for a passphrase.
215: The passphrase may be empty to indicate no passphrase
1.26 markus 216: (host keys must have an empty passphrase), or it may be a string of
1.12 aaron 217: arbitrary length.
1.51 stevesk 218: A passphrase is similar to a password, except it can be a phrase with a
219: series of words, punctuation, numbers, whitespace, or any string of
220: characters you want.
221: Good passphrases are 10-30 characters long, are
1.1 deraadt 222: not simple sentences or otherwise easily guessable (English
1.42 markus 223: prose has only 1-2 bits of entropy per character, and provides very bad
1.51 stevesk 224: passphrases), and contain a mix of upper and lowercase letters,
225: numbers, and non-alphanumeric characters.
1.12 aaron 226: The passphrase can be changed later by using the
1.2 deraadt 227: .Fl p
1.1 deraadt 228: option.
1.2 deraadt 229: .Pp
1.12 aaron 230: There is no way to recover a lost passphrase.
1.105 djm 231: If the passphrase is lost or forgotten, a new key must be generated
232: and the corresponding public key copied to other machines.
1.2 deraadt 233: .Pp
1.153 djm 234: .Nm
235: will by default write keys in an OpenSSH-specific format.
236: This format is preferred as it offers better protection for
237: keys at rest as well as allowing storage of key comments within
238: the private key file itself.
239: The key comment may be useful to help identify the key.
1.12 aaron 240: The comment is initialized to
1.2 deraadt 241: .Dq user@host
242: when the key is created, but can be changed using the
243: .Fl c
1.1 deraadt 244: option.
1.153 djm 245: .Pp
246: It is still possible for
247: .Nm
248: to write the previously-used PEM format private keys using the
249: .Fl m
250: flag.
251: This may be used when generating new keys, and existing new-format
252: keys may be converted using this option in conjunction with the
253: .Fl p
254: (change passphrase) flag.
1.2 deraadt 255: .Pp
1.205 ! solene 256: After a key is generated,
! 257: .Nm
! 258: will ask where the keys
1.15 deraadt 259: should be placed to be activated.
260: .Pp
1.2 deraadt 261: The options are as follows:
262: .Bl -tag -width Ds
1.102 stevesk 263: .It Fl A
1.175 djm 264: For each of the key types (rsa, dsa, ecdsa and ed25519)
1.118 naddy 265: for which host keys
1.102 stevesk 266: do not exist, generate the host keys with the default key file path,
267: an empty passphrase, default bits for the key type, and default comment.
1.144 jmc 268: If
1.143 djm 269: .Fl f
1.144 jmc 270: has also been specified, its argument is used as a prefix to the
1.143 djm 271: default path for the resulting host key files.
1.104 jmc 272: This is used by
1.102 stevesk 273: .Pa /etc/rc
274: to generate new host keys.
1.117 djm 275: .It Fl a Ar rounds
1.169 jmc 276: When saving a private key, this option specifies the number of KDF
1.148 djm 277: (key derivation function) rounds used.
1.117 djm 278: Higher numbers result in slower passphrase verification and increased
279: resistance to brute-force password cracking (should the keys be stolen).
1.204 dtucker 280: The default is 16 rounds.
1.66 jmc 281: .It Fl B
282: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 283: .It Fl b Ar bits
1.12 aaron 284: Specifies the number of bits in the key to create.
1.158 dtucker 285: For RSA keys, the minimum size is 1024 bits and the default is 3072 bits.
286: Generally, 3072 bits is considered sufficient.
1.72 dtucker 287: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.106 djm 288: For ECDSA keys, the
289: .Fl b
1.107 deraadt 290: flag determines the key length by selecting from one of three elliptic
1.106 djm 291: curve sizes: 256, 384 or 521 bits.
292: Attempting to use bit lengths other than these three values for ECDSA keys
293: will fail.
1.176 naddy 294: ECDSA-SK, Ed25519 and Ed25519-SK keys have a fixed length and the
1.118 naddy 295: .Fl b
296: flag will be ignored.
1.66 jmc 297: .It Fl C Ar comment
298: Provides a new comment.
1.2 deraadt 299: .It Fl c
1.1 deraadt 300: Requests changing the comment in the private and public key files.
301: The program will prompt for the file containing the private keys, for
1.41 stevesk 302: the passphrase if the key has one, and for the new comment.
1.81 markus 303: .It Fl D Ar pkcs11
1.157 naddy 304: Download the public keys provided by the PKCS#11 shared library
1.83 markus 305: .Ar pkcs11 .
1.98 djm 306: When used in combination with
307: .Fl s ,
308: this option indicates that a CA key resides in a PKCS#11 token (see the
309: .Sx CERTIFICATES
310: section for details).
1.124 djm 311: .It Fl E Ar fingerprint_hash
312: Specifies the hash algorithm used when displaying key fingerprints.
313: Valid options are:
314: .Dq md5
315: and
316: .Dq sha256 .
317: The default is
318: .Dq sha256 .
1.37 markus 319: .It Fl e
1.40 markus 320: This option will read a private or public OpenSSH key file and
1.154 djm 321: print to stdout a public key in one of the formats specified by the
1.95 djm 322: .Fl m
323: option.
324: The default export format is
325: .Dq RFC4716 .
1.96 jmc 326: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 327: several commercial SSH implementations.
1.151 djm 328: .It Fl F Ar hostname | [hostname]:port
1.66 jmc 329: Search for the specified
330: .Ar hostname
1.151 djm 331: (with optional port number)
1.66 jmc 332: in a
333: .Pa known_hosts
334: file, listing any occurrences found.
335: This option is useful to find hashed host names or addresses and may also be
336: used in conjunction with the
337: .Fl H
338: option to print found keys in a hashed format.
339: .It Fl f Ar filename
340: Specifies the filename of the key file.
1.57 jakob 341: .It Fl g
1.62 jakob 342: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 343: .Fl r
1.62 jakob 344: command.
1.66 jmc 345: .It Fl H
346: Hash a
347: .Pa known_hosts
1.67 dtucker 348: file.
349: This replaces all hostnames and addresses with hashed representations
350: within the specified file; the original content is moved to a file with
351: a .old suffix.
1.66 jmc 352: These hashes may be used normally by
353: .Nm ssh
354: and
355: .Nm sshd ,
356: but they do not reveal identifying information should the file's contents
357: be disclosed.
358: This option will not modify existing hashed hostnames and is therefore safe
359: to use on files that mix hashed and non-hashed names.
1.84 djm 360: .It Fl h
361: When signing a key, create a host certificate instead of a user
362: certificate.
363: Please see the
364: .Sx CERTIFICATES
365: section for details.
1.85 jmc 366: .It Fl I Ar certificate_identity
1.84 djm 367: Specify the key identity when signing a public key.
368: Please see the
369: .Sx CERTIFICATES
370: section for details.
1.37 markus 371: .It Fl i
372: This option will read an unencrypted private (or public) key file
1.95 djm 373: in the format specified by the
374: .Fl m
375: option and print an OpenSSH compatible private
1.37 markus 376: (or public) key to stdout.
1.122 jmc 377: This option allows importing keys from other software, including several
378: commercial SSH implementations.
379: The default import format is
380: .Dq RFC4716 .
1.188 jmc 381: .It Fl K
1.187 djm 382: Download resident keys from a FIDO authenticator.
383: Public and private key files will be written to the current directory for
384: each downloaded key.
1.111 djm 385: .It Fl k
386: Generate a KRL file.
387: In this mode,
388: .Nm
389: will generate a KRL file at the location specified via the
390: .Fl f
1.114 jmc 391: flag that revokes every key or certificate presented on the command line.
1.111 djm 392: Keys/certificates to be revoked may be specified by public key file or
393: using the format described in the
394: .Sx KEY REVOCATION LISTS
395: section.
1.86 djm 396: .It Fl L
1.129 djm 397: Prints the contents of one or more certificates.
1.9 markus 398: .It Fl l
1.77 grunk 399: Show fingerprint of specified public key file.
1.50 markus 400: For RSA and DSA keys
401: .Nm
1.78 jmc 402: tries to find the matching public key file and prints its fingerprint.
403: If combined with
404: .Fl v ,
1.132 jmc 405: a visual ASCII art representation of the key is supplied with the
1.131 djm 406: fingerprint.
1.184 djm 407: .It Fl M Cm generate
408: Generate candidate Diffie-Hellman Group Exchange (DH-GEX) parameters for
409: eventual use by the
410: .Sq diffie-hellman-group-exchange-*
411: key exchange methods.
412: The numbers generated by this operation must be further screened before
413: use.
414: See the
415: .Sx MODULI GENERATION
416: section for more information.
417: .It Fl M Cm screen
418: Screen candidate parameters for Diffie-Hellman Group Exchange.
419: This will accept a list of candidate numbers and test that they are
420: safe (Sophie Germain) primes with acceptable group generators.
421: The results of this operation may be added to the
422: .Pa /etc/moduli
423: file.
424: See the
425: .Sx MODULI GENERATION
426: section for more information.
1.95 djm 427: .It Fl m Ar key_format
1.155 djm 428: Specify a key format for key generation, the
1.95 djm 429: .Fl i
1.155 djm 430: (import),
1.95 djm 431: .Fl e
1.155 djm 432: (export) conversion options, and the
433: .Fl p
434: change passphrase operation.
435: The latter may be used to convert between OpenSSH private key and PEM
436: private key formats.
1.95 djm 437: The supported key formats are:
438: .Dq RFC4716
1.96 jmc 439: (RFC 4716/SSH2 public or private key),
1.95 djm 440: .Dq PKCS8
1.161 djm 441: (PKCS8 public or private key)
1.95 djm 442: or
443: .Dq PEM
444: (PEM public key).
1.161 djm 445: By default OpenSSH will write newly-generated private keys in its own
446: format, but when converting public keys for export the default format is
1.95 djm 447: .Dq RFC4716 .
1.148 djm 448: Setting a format of
449: .Dq PEM
450: when generating or updating a supported private key type will cause the
451: key to be stored in the legacy PEM private key format.
1.66 jmc 452: .It Fl N Ar new_passphrase
453: Provides the new passphrase.
1.84 djm 454: .It Fl n Ar principals
455: Specify one or more principals (user or host names) to be included in
456: a certificate when signing a key.
457: Multiple principals may be specified, separated by commas.
458: Please see the
459: .Sx CERTIFICATES
460: section for details.
1.93 djm 461: .It Fl O Ar option
1.184 djm 462: Specify a key/value option.
463: These are specific to the operation that
464: .Nm
465: has been requested to perform.
466: .Pp
467: When signing certificates, one of the options listed in the
1.183 djm 468: .Sx CERTIFICATES
1.184 djm 469: section may be specified here.
470: .Pp
471: When performing moduli generation or screening, one of the options
472: listed in the
473: .Sx MODULI GENERATION
474: section may be specified.
475: .Pp
1.190 jmc 476: When generating a key that will be hosted on a FIDO authenticator,
477: this flag may be used to specify key-specific options.
478: Those supported at present are:
479: .Bl -tag -width Ds
480: .It Cm application
481: Override the default FIDO application/origin string of
1.189 djm 482: .Dq ssh: .
1.190 jmc 483: This may be useful when generating host or domain-specific resident keys.
1.200 djm 484: The specified application string must begin with
485: .Dq ssh: .
1.199 jmc 486: .It Cm challenge Ns = Ns Ar path
1.198 jmc 487: Specifies a path to a challenge string that will be passed to the
488: FIDO token during key generation.
1.199 jmc 489: The challenge string may be used as part of an out-of-band
490: protocol for key enrollment
491: (a random challenge is used by default).
1.190 jmc 492: .It Cm device
493: Explicitly specify a
1.189 djm 494: .Xr fido 4
495: device to use, rather than letting the token middleware select one.
1.190 jmc 496: .It Cm no-touch-required
497: Indicate that the generated private key should not require touch
1.185 djm 498: events (user presence) when making signatures.
499: Note that
500: .Xr sshd 8
501: will refuse such signatures by default, unless overridden via
502: an authorized_keys option.
1.190 jmc 503: .It Cm resident
504: Indicate that the key should be stored on the FIDO authenticator itself.
1.185 djm 505: Resident keys may be supported on FIDO2 tokens and typically require that
506: a PIN be set on the token prior to generation.
507: Resident keys may be loaded off the token using
508: .Xr ssh-add 1 .
1.190 jmc 509: .It Cm user
510: A username to be associated with a resident key,
1.189 djm 511: overriding the empty default username.
512: Specifying a username may be useful when generating multiple resident keys
513: for the same application name.
1.199 jmc 514: .It Cm write-attestation Ns = Ns Ar path
1.197 djm 515: May be used at key generation time to record the attestation certificate
516: returned from FIDO tokens during key generation.
517: By default this information is discarded.
1.190 jmc 518: .El
1.185 djm 519: .Pp
520: The
521: .Fl O
522: option may be specified multiple times.
1.66 jmc 523: .It Fl P Ar passphrase
524: Provides the (old) passphrase.
1.2 deraadt 525: .It Fl p
1.1 deraadt 526: Requests changing the passphrase of a private key file instead of
1.12 aaron 527: creating a new private key.
528: The program will prompt for the file
1.1 deraadt 529: containing the private key, for the old passphrase, and twice for the
530: new passphrase.
1.113 jmc 531: .It Fl Q
532: Test whether keys have been revoked in a KRL.
1.203 djm 533: If the
534: .Fl l
535: option is also specified then the contents of the KRL will be printed.
1.5 aaron 536: .It Fl q
537: Silence
538: .Nm ssh-keygen .
1.152 djm 539: .It Fl R Ar hostname | [hostname]:port
1.151 djm 540: Removes all keys belonging to the specified
1.64 djm 541: .Ar hostname
1.151 djm 542: (with optional port number)
1.65 jmc 543: from a
1.64 djm 544: .Pa known_hosts
545: file.
1.65 jmc 546: This option is useful to delete hashed hosts (see the
1.64 djm 547: .Fl H
548: option above).
1.66 jmc 549: .It Fl r Ar hostname
550: Print the SSHFP fingerprint resource record named
551: .Ar hostname
552: for the specified public key file.
1.84 djm 553: .It Fl s Ar ca_key
554: Certify (sign) a public key using the specified CA key.
555: Please see the
556: .Sx CERTIFICATES
557: section for details.
1.111 djm 558: .Pp
559: When generating a KRL,
560: .Fl s
1.112 jmc 561: specifies a path to a CA public key file used to revoke certificates directly
1.111 djm 562: by key ID or serial number.
563: See the
564: .Sx KEY REVOCATION LISTS
565: section for details.
1.175 djm 566: .It Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
1.66 jmc 567: Specifies the type of key to create.
568: The possible values are
1.100 naddy 569: .Dq dsa ,
1.118 naddy 570: .Dq ecdsa ,
1.173 naddy 571: .Dq ecdsa-sk ,
1.118 naddy 572: .Dq ed25519 ,
1.175 djm 573: .Dq ed25519-sk ,
1.100 naddy 574: or
1.139 jmc 575: .Dq rsa .
1.159 djm 576: .Pp
577: This flag may also be used to specify the desired signature type when
1.160 jmc 578: signing certificates using an RSA CA key.
1.159 djm 579: The available RSA signature variants are
580: .Dq ssh-rsa
581: (SHA1 signatures, not recommended),
1.160 jmc 582: .Dq rsa-sha2-256 ,
583: and
1.159 djm 584: .Dq rsa-sha2-512
585: (the default).
1.142 djm 586: .It Fl U
587: When used in combination with
588: .Fl s ,
589: this option indicates that a CA key resides in a
590: .Xr ssh-agent 1 .
591: See the
592: .Sx CERTIFICATES
593: section for more information.
1.112 jmc 594: .It Fl u
595: Update a KRL.
596: When specified with
597: .Fl k ,
1.114 jmc 598: keys listed via the command line are added to the existing KRL rather than
1.112 jmc 599: a new KRL being created.
1.84 djm 600: .It Fl V Ar validity_interval
601: Specify a validity interval when signing a certificate.
602: A validity interval may consist of a single time, indicating that the
603: certificate is valid beginning now and expiring at that time, or may consist
604: of two times separated by a colon to indicate an explicit time interval.
1.145 djm 605: .Pp
606: The start time may be specified as the string
607: .Dq always
608: to indicate the certificate has no specified start time,
1.147 djm 609: a date in YYYYMMDD format, a time in YYYYMMDDHHMM[SS] format,
1.145 djm 610: a relative time (to the current time) consisting of a minus sign followed by
611: an interval in the format described in the
1.116 jmc 612: TIME FORMATS section of
1.90 jmc 613: .Xr sshd_config 5 .
1.145 djm 614: .Pp
1.147 djm 615: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMM[SS] time,
1.145 djm 616: a relative time starting with a plus character or the string
617: .Dq forever
1.202 dtucker 618: to indicate that the certificate has no expiry date.
1.84 djm 619: .Pp
620: For example:
621: .Dq +52w1d
622: (valid from now to 52 weeks and one day from now),
623: .Dq -4w:+4w
624: (valid from four weeks ago to four weeks from now),
625: .Dq 20100101123000:20110101123000
626: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
627: .Dq -1d:20110101
628: (valid from yesterday to midnight, January 1st, 2011).
1.145 djm 629: .Dq -1m:forever
630: (valid from one minute ago and never expiring).
1.61 djm 631: .It Fl v
632: Verbose mode.
633: Causes
634: .Nm
635: to print debugging messages about its progress.
636: This is helpful for debugging moduli generation.
637: Multiple
638: .Fl v
639: options increase the verbosity.
640: The maximum is 3.
1.173 naddy 641: .It Fl w Ar provider
1.180 naddy 642: Specifies a path to a library that will be used when creating
643: FIDO authenticator-hosted keys, overriding the default of using
644: the internal USB HID support.
1.196 djm 645: .It Fl Y Cm find-principals
646: Find the principal(s) associated with the public key of a signature,
1.194 djm 647: provided using the
648: .Fl s
649: flag in an authorized signers file provided using the
650: .Fl f
651: flag.
652: The format of the allowed signers file is documented in the
653: .Sx ALLOWED SIGNERS
1.195 jmc 654: section below.
1.196 djm 655: If one or more matching principals are found, they are returned on
656: standard output.
1.182 jmc 657: .It Fl Y Cm check-novalidate
658: Checks that a signature generated using
659: .Nm
660: .Fl Y Cm sign
661: has a valid structure.
662: This does not validate if a signature comes from an authorized signer.
663: When testing a signature,
664: .Nm
665: accepts a message on standard input and a signature namespace using
666: .Fl n .
667: A file containing the corresponding signature must also be supplied using the
668: .Fl s
669: flag.
670: Successful testing of the signature is signalled by
671: .Nm
672: returning a zero exit status.
1.166 jmc 673: .It Fl Y Cm sign
1.163 djm 674: Cryptographically sign a file or some data using a SSH key.
675: When signing,
676: .Nm
677: accepts zero or more files to sign on the command-line - if no files
678: are specified then
679: .Nm
680: will sign data presented on standard input.
681: Signatures are written to the path of the input file with
682: .Dq .sig
683: appended, or to standard output if the message to be signed was read from
684: standard input.
685: .Pp
686: The key used for signing is specified using the
687: .Fl f
688: option and may refer to either a private key, or a public key with the private
689: half available via
690: .Xr ssh-agent 1 .
691: An additional signature namespace, used to prevent signature confusion across
692: different domains of use (e.g. file signing vs email signing) must be provided
693: via the
694: .Fl n
695: flag.
696: Namespaces are arbitrary strings, and may include:
697: .Dq file
698: for file signing,
699: .Dq email
700: for email signing.
701: For custom uses, it is recommended to use names following a
702: NAMESPACE@YOUR.DOMAIN pattern to generate unambiguous namespaces.
1.166 jmc 703: .It Fl Y Cm verify
1.163 djm 704: Request to verify a signature generated using
705: .Nm
1.166 jmc 706: .Fl Y Cm sign
1.163 djm 707: as described above.
708: When verifying a signature,
709: .Nm
710: accepts a message on standard input and a signature namespace using
711: .Fl n .
712: A file containing the corresponding signature must also be supplied using the
713: .Fl s
714: flag, along with the identity of the signer using
715: .Fl I
716: and a list of allowed signers via the
717: .Fl f
718: flag.
719: The format of the allowed signers file is documented in the
720: .Sx ALLOWED SIGNERS
721: section below.
722: A file containing revoked keys can be passed using the
723: .Fl r
1.165 jmc 724: flag.
725: The revocation file may be a KRL or a one-per-line list of public keys.
1.163 djm 726: Successful verification by an authorized signer is signalled by
727: .Nm
728: returning a zero exit status.
1.181 jmc 729: .It Fl y
730: This option will read a private
731: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 732: .It Fl z Ar serial_number
733: Specifies a serial number to be embedded in the certificate to distinguish
734: this certificate from others from the same CA.
1.156 djm 735: If the
736: .Ar serial_number
737: is prefixed with a
738: .Sq +
739: character, then the serial number will be incremented for each certificate
740: signed on a single command-line.
1.93 djm 741: The default serial number is zero.
1.111 djm 742: .Pp
743: When generating a KRL, the
744: .Fl z
745: flag is used to specify a KRL version number.
1.2 deraadt 746: .El
1.60 djm 747: .Sh MODULI GENERATION
748: .Nm
749: may be used to generate groups for the Diffie-Hellman Group Exchange
750: (DH-GEX) protocol.
751: Generating these groups is a two-step process: first, candidate
752: primes are generated using a fast, but memory intensive process.
753: These candidate primes are then tested for suitability (a CPU-intensive
754: process).
755: .Pp
756: Generation of primes is performed using the
1.184 djm 757: .Fl M Cm generate
1.60 djm 758: option.
759: The desired length of the primes may be specified by the
1.184 djm 760: .Fl O Cm bits
1.60 djm 761: option.
762: For example:
763: .Pp
1.184 djm 764: .Dl # ssh-keygen -M generate -O bits=2048 moduli-2048.candidates
1.60 djm 765: .Pp
766: By default, the search for primes begins at a random point in the
767: desired length range.
768: This may be overridden using the
1.184 djm 769: .Fl O Cm start
1.60 djm 770: option, which specifies a different start point (in hex).
771: .Pp
1.109 dtucker 772: Once a set of candidates have been generated, they must be screened for
1.60 djm 773: suitability.
774: This may be performed using the
1.184 djm 775: .Fl M Cm screen
1.60 djm 776: option.
777: In this mode
778: .Nm
779: will read candidates from standard input (or a file specified using the
780: .Fl f
781: option).
782: For example:
783: .Pp
1.184 djm 784: .Dl # ssh-keygen -M screen -f moduli-2048.candidates moduli-2048
1.60 djm 785: .Pp
786: By default, each candidate will be subjected to 100 primality tests.
787: This may be overridden using the
1.184 djm 788: .Fl O Cm prime-tests
1.60 djm 789: option.
790: The DH generator value will be chosen automatically for the
791: prime under consideration.
792: If a specific generator is desired, it may be requested using the
1.184 djm 793: .Fl O Cm generator
1.60 djm 794: option.
1.66 jmc 795: Valid generator values are 2, 3, and 5.
1.60 djm 796: .Pp
797: Screened DH groups may be installed in
798: .Pa /etc/moduli .
799: It is important that this file contains moduli of a range of bit lengths and
800: that both ends of a connection share common moduli.
1.184 djm 801: .Pp
802: A number of options are available for moduli generation and screening via the
803: .Fl O
804: flag:
1.186 jmc 805: .Bl -tag -width Ds
1.184 djm 806: .It Ic lines Ns = Ns Ar number
807: Exit after screening the specified number of lines while performing DH
808: candidate screening.
809: .It Ic start-line Ns = Ns Ar line-number
810: Start screening at the specified line number while performing DH candidate
811: screening.
812: .It Ic checkpoint Ns = Ns Ar filename
813: Write the last line processed to the specified file while performing DH
814: candidate screening.
815: This will be used to skip lines in the input file that have already been
816: processed if the job is restarted.
817: .It Ic memory Ns = Ns Ar mbytes
818: Specify the amount of memory to use (in megabytes) when generating
819: candidate moduli for DH-GEX.
820: .It Ic start Ns = Ns Ar hex-value
821: Specify start point (in hex) when generating candidate moduli for DH-GEX.
822: .It Ic generator Ns = Ns Ar value
823: Specify desired generator (in decimal) when testing candidate moduli for DH-GEX.
824: .El
1.84 djm 825: .Sh CERTIFICATES
826: .Nm
827: supports signing of keys to produce certificates that may be used for
828: user or host authentication.
829: Certificates consist of a public key, some identity information, zero or
1.94 jmc 830: more principal (user or host) names and a set of options that
1.84 djm 831: are signed by a Certification Authority (CA) key.
832: Clients or servers may then trust only the CA key and verify its signature
833: on a certificate rather than trusting many user/host keys.
834: Note that OpenSSH certificates are a different, and much simpler, format to
835: the X.509 certificates used in
836: .Xr ssl 8 .
837: .Pp
838: .Nm
839: supports two types of certificates: user and host.
840: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 841: authenticate server hosts to users.
842: To generate a user certificate:
1.84 djm 843: .Pp
844: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
845: .Pp
846: The resultant certificate will be placed in
1.91 djm 847: .Pa /path/to/user_key-cert.pub .
1.84 djm 848: A host certificate requires the
849: .Fl h
850: option:
851: .Pp
852: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
853: .Pp
854: The host certificate will be output to
1.91 djm 855: .Pa /path/to/host_key-cert.pub .
1.98 djm 856: .Pp
857: It is possible to sign using a CA key stored in a PKCS#11 token by
858: providing the token library using
859: .Fl D
860: and identifying the CA key by providing its public half as an argument
861: to
862: .Fl s :
863: .Pp
1.127 naddy 864: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id user_key.pub
1.142 djm 865: .Pp
866: Similarly, it is possible for the CA key to be hosted in a
867: .Xr ssh-agent 1 .
868: This is indicated by the
869: .Fl U
870: flag and, again, the CA key must be identified by its public half.
871: .Pp
872: .Dl $ ssh-keygen -Us ca_key.pub -I key_id user_key.pub
1.98 djm 873: .Pp
874: In all cases,
1.84 djm 875: .Ar key_id
876: is a "key identifier" that is logged by the server when the certificate
877: is used for authentication.
878: .Pp
879: Certificates may be limited to be valid for a set of principal (user/host)
880: names.
881: By default, generated certificates are valid for all users or hosts.
882: To generate a certificate for a specified set of principals:
883: .Pp
884: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.127 naddy 885: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain host_key.pub"
1.84 djm 886: .Pp
887: Additional limitations on the validity and use of user certificates may
1.94 jmc 888: be specified through certificate options.
1.93 djm 889: A certificate option may disable features of the SSH session, may be
1.84 djm 890: valid only when presented from particular source addresses or may
891: force the use of a specific command.
1.183 djm 892: .Pp
893: The options that are valid for user certificates are:
894: .Pp
895: .Bl -tag -width Ds -compact
896: .It Ic clear
897: Clear all enabled permissions.
898: This is useful for clearing the default set of permissions so permissions may
899: be added individually.
900: .Pp
901: .It Ic critical : Ns Ar name Ns Op Ns = Ns Ar contents
902: .It Ic extension : Ns Ar name Ns Op Ns = Ns Ar contents
903: Includes an arbitrary certificate critical option or extension.
904: The specified
905: .Ar name
906: should include a domain suffix, e.g.\&
907: .Dq name@example.com .
908: If
909: .Ar contents
910: is specified then it is included as the contents of the extension/option
911: encoded as a string, otherwise the extension/option is created with no
912: contents (usually indicating a flag).
913: Extensions may be ignored by a client or server that does not recognise them,
914: whereas unknown critical options will cause the certificate to be refused.
915: .Pp
916: .It Ic force-command Ns = Ns Ar command
917: Forces the execution of
918: .Ar command
919: instead of any shell or command specified by the user when
920: the certificate is used for authentication.
921: .Pp
922: .It Ic no-agent-forwarding
923: Disable
924: .Xr ssh-agent 1
925: forwarding (permitted by default).
926: .Pp
927: .It Ic no-port-forwarding
928: Disable port forwarding (permitted by default).
929: .Pp
930: .It Ic no-pty
931: Disable PTY allocation (permitted by default).
932: .Pp
933: .It Ic no-user-rc
934: Disable execution of
935: .Pa ~/.ssh/rc
936: by
937: .Xr sshd 8
938: (permitted by default).
939: .Pp
940: .It Ic no-x11-forwarding
941: Disable X11 forwarding (permitted by default).
942: .Pp
943: .It Ic permit-agent-forwarding
944: Allows
945: .Xr ssh-agent 1
946: forwarding.
947: .Pp
948: .It Ic permit-port-forwarding
949: Allows port forwarding.
950: .Pp
951: .It Ic permit-pty
952: Allows PTY allocation.
953: .Pp
954: .It Ic permit-user-rc
955: Allows execution of
956: .Pa ~/.ssh/rc
957: by
958: .Xr sshd 8 .
959: .Pp
960: .It Ic permit-X11-forwarding
961: Allows X11 forwarding.
962: .Pp
963: .It Ic no-touch-required
964: Do not require signatures made using this key require demonstration
1.193 naddy 965: of user presence (e.g. by having the user touch the authenticator).
1.192 naddy 966: This option only makes sense for the FIDO authenticator algorithms
1.183 djm 967: .Cm ecdsa-sk
968: and
969: .Cm ed25519-sk .
970: .Pp
971: .It Ic source-address Ns = Ns Ar address_list
972: Restrict the source addresses from which the certificate is considered valid.
973: The
974: .Ar address_list
975: is a comma-separated list of one or more address/netmask pairs in CIDR
976: format.
977: .El
978: .Pp
979: At present, no standard options are valid for host keys.
1.84 djm 980: .Pp
981: Finally, certificates may be defined with a validity lifetime.
982: The
983: .Fl V
984: option allows specification of certificate start and end times.
985: A certificate that is presented at a time outside this range will not be
986: considered valid.
1.110 jmc 987: By default, certificates are valid from
988: .Ux
989: Epoch to the distant future.
1.84 djm 990: .Pp
991: For certificates to be used for user or host authentication, the CA
992: public key must be trusted by
993: .Xr sshd 8
994: or
995: .Xr ssh 1 .
996: Please refer to those manual pages for details.
1.111 djm 997: .Sh KEY REVOCATION LISTS
998: .Nm
999: is able to manage OpenSSH format Key Revocation Lists (KRLs).
1000: These binary files specify keys or certificates to be revoked using a
1.119 tedu 1001: compact format, taking as little as one bit per certificate if they are being
1.111 djm 1002: revoked by serial number.
1003: .Pp
1004: KRLs may be generated using the
1005: .Fl k
1006: flag.
1.114 jmc 1007: This option reads one or more files from the command line and generates a new
1.111 djm 1008: KRL.
1009: The files may either contain a KRL specification (see below) or public keys,
1010: listed one per line.
1011: Plain public keys are revoked by listing their hash or contents in the KRL and
1012: certificates revoked by serial number or key ID (if the serial is zero or
1013: not available).
1014: .Pp
1015: Revoking keys using a KRL specification offers explicit control over the
1016: types of record used to revoke keys and may be used to directly revoke
1017: certificates by serial number or key ID without having the complete original
1018: certificate on hand.
1019: A KRL specification consists of lines containing one of the following directives
1020: followed by a colon and some directive-specific information.
1021: .Bl -tag -width Ds
1.115 jmc 1022: .It Cm serial : Ar serial_number Ns Op - Ns Ar serial_number
1.111 djm 1023: Revokes a certificate with the specified serial number.
1.112 jmc 1024: Serial numbers are 64-bit values, not including zero and may be expressed
1.111 djm 1025: in decimal, hex or octal.
1026: If two serial numbers are specified separated by a hyphen, then the range
1027: of serial numbers including and between each is revoked.
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 id : Ar key_id
1034: Revokes a certificate with the specified key ID string.
1035: The CA key must have been specified on the
1036: .Nm
1.114 jmc 1037: command line using the
1.111 djm 1038: .Fl s
1039: option.
1040: .It Cm key : Ar public_key
1041: Revokes the specified key.
1.112 jmc 1042: If a certificate is listed, then it is revoked as a plain public key.
1.111 djm 1043: .It Cm sha1 : Ar public_key
1.149 djm 1044: Revokes the specified key by including its SHA1 hash in the KRL.
1045: .It Cm sha256 : Ar public_key
1046: Revokes the specified key by including its SHA256 hash in the KRL.
1047: KRLs that revoke keys by SHA256 hash are not supported by OpenSSH versions
1048: prior to 7.9.
1049: .It Cm hash : Ar fingerprint
1.150 djm 1050: Revokes a key using a fingerprint hash, as obtained from a
1.149 djm 1051: .Xr sshd 8
1052: authentication log message or the
1053: .Nm
1054: .Fl l
1055: flag.
1056: Only SHA256 fingerprints are supported here and resultant KRLs are
1057: not supported by OpenSSH versions prior to 7.9.
1.111 djm 1058: .El
1059: .Pp
1060: KRLs may be updated using the
1061: .Fl u
1062: flag in addition to
1063: .Fl k .
1.114 jmc 1064: When this option is specified, keys listed via the command line are merged into
1.111 djm 1065: the KRL, adding to those already there.
1066: .Pp
1067: It is also possible, given a KRL, to test whether it revokes a particular key
1068: (or keys).
1069: The
1070: .Fl Q
1.128 jmc 1071: flag will query an existing KRL, testing each key specified on the command line.
1.114 jmc 1072: If any key listed on the command line has been revoked (or an error encountered)
1.111 djm 1073: then
1074: .Nm
1075: will exit with a non-zero exit status.
1076: A zero exit status will only be returned if no key was revoked.
1.163 djm 1077: .Sh ALLOWED SIGNERS
1078: When verifying signatures,
1079: .Nm
1080: uses a simple list of identities and keys to determine whether a signature
1081: comes from an authorized source.
1082: This "allowed signers" file uses a format patterned after the
1083: AUTHORIZED_KEYS FILE FORMAT described in
1.165 jmc 1084: .Xr sshd 8 .
1.163 djm 1085: Each line of the file contains the following space-separated fields:
1086: principals, options, keytype, base64-encoded key.
1087: Empty lines and lines starting with a
1088: .Ql #
1089: are ignored as comments.
1090: .Pp
1091: The principals field is a pattern-list (See PATTERNS in
1092: .Xr ssh_config 5 )
1093: consisting of one or more comma-separated USER@DOMAIN identity patterns
1094: that are accepted for signing.
1095: When verifying, the identity presented via the
1.172 jmc 1096: .Fl I
1097: option must match a principals pattern in order for the corresponding key to be
1.163 djm 1098: considered acceptable for verification.
1099: .Pp
1100: The options (if present) consist of comma-separated option specifications.
1101: No spaces are permitted, except within double quotes.
1102: The following option specifications are supported (note that option keywords
1103: are case-insensitive):
1104: .Bl -tag -width Ds
1105: .It Cm cert-authority
1106: Indicates that this key is accepted as a certificate authority (CA) and
1107: that certificates signed by this CA may be accepted for verification.
1108: .It Cm namespaces="namespace-list"
1109: Specifies a pattern-list of namespaces that are accepted for this key.
1.164 djm 1110: If this option is present, the signature namespace embedded in the
1.163 djm 1111: signature object and presented on the verification command-line must
1112: match the specified list before the key will be considered acceptable.
1113: .El
1114: .Pp
1115: When verifying signatures made by certificates, the expected principal
1116: name must match both the principals pattern in the allowed signers file and
1117: the principals embedded in the certificate itself.
1118: .Pp
1119: An example allowed signers file:
1120: .Bd -literal -offset 3n
1121: # Comments allowed at start of line
1122: user1@example.com,user2@example.com ssh-rsa AAAAX1...
1123: # A certificate authority, trusted for all principals in a domain.
1124: *@example.com cert-authority ssh-ed25519 AAAB4...
1125: # A key that is accepted only for file signing.
1126: user2@example.com namespaces="file" ssh-ed25519 AAA41...
1127: .Ed
1.173 naddy 1128: .Sh ENVIRONMENT
1129: .Bl -tag -width Ds
1130: .It Ev SSH_SK_PROVIDER
1.201 djm 1131: Specifies a path to a library that will be used when loading any
1132: FIDO authenticator-hosted keys, overriding the default of using
1133: the built-in USB HID support.
1.173 naddy 1134: .El
1.2 deraadt 1135: .Sh FILES
1.100 naddy 1136: .Bl -tag -width Ds -compact
1.68 djm 1137: .It Pa ~/.ssh/id_dsa
1.100 naddy 1138: .It Pa ~/.ssh/id_ecdsa
1.173 naddy 1139: .It Pa ~/.ssh/id_ecdsa_sk
1.118 naddy 1140: .It Pa ~/.ssh/id_ed25519
1.176 naddy 1141: .It Pa ~/.ssh/id_ed25519_sk
1.100 naddy 1142: .It Pa ~/.ssh/id_rsa
1.180 naddy 1143: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1144: authenticator-hosted Ed25519 or RSA authentication identity of the user.
1.15 deraadt 1145: This file should not be readable by anyone but the user.
1146: It is possible to
1147: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 1148: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 1149: This file is not automatically accessed by
1150: .Nm
1151: but it is offered as the default file for the private key.
1.46 markus 1152: .Xr ssh 1
1.15 deraadt 1153: will read this file when a login attempt is made.
1.100 naddy 1154: .Pp
1.68 djm 1155: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 1156: .It Pa ~/.ssh/id_ecdsa.pub
1.173 naddy 1157: .It Pa ~/.ssh/id_ecdsa_sk.pub
1.118 naddy 1158: .It Pa ~/.ssh/id_ed25519.pub
1.176 naddy 1159: .It Pa ~/.ssh/id_ed25519_sk.pub
1.68 djm 1160: .It Pa ~/.ssh/id_rsa.pub
1.180 naddy 1161: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1162: authenticator-hosted Ed25519 or RSA public key for authentication.
1.15 deraadt 1163: The contents of this file should be added to
1.68 djm 1164: .Pa ~/.ssh/authorized_keys
1.15 deraadt 1165: on all machines
1.49 deraadt 1166: where the user wishes to log in using public key authentication.
1.12 aaron 1167: There is no need to keep the contents of this file secret.
1.100 naddy 1168: .Pp
1.60 djm 1169: .It Pa /etc/moduli
1170: Contains Diffie-Hellman groups used for DH-GEX.
1171: The file format is described in
1172: .Xr moduli 5 .
1.19 aaron 1173: .El
1.2 deraadt 1174: .Sh SEE ALSO
1175: .Xr ssh 1 ,
1176: .Xr ssh-add 1 ,
1.8 ericj 1177: .Xr ssh-agent 1 ,
1.60 djm 1178: .Xr moduli 5 ,
1.30 itojun 1179: .Xr sshd 8
1.37 markus 1180: .Rs
1.73 markus 1181: .%R RFC 4716
1182: .%T "The Secure Shell (SSH) Public Key File Format"
1183: .%D 2006
1.37 markus 1184: .Re
1.59 jmc 1185: .Sh AUTHORS
1186: OpenSSH is a derivative of the original and free
1187: ssh 1.2.12 release by Tatu Ylonen.
1188: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
1189: Theo de Raadt and Dug Song
1190: removed many bugs, re-added newer features and
1191: created OpenSSH.
1192: Markus Friedl contributed the support for SSH
1193: protocol versions 1.5 and 2.0.
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