Annotation of src/usr.bin/ssh/ssh-keygen.1, Revision 1.211
1.211 ! dtucker 1: .\" $OpenBSD: ssh-keygen.1,v 1.210 2020/10/26 00:39:04 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
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: .\"
1.211 ! dtucker 38: .Dd $Mdocdate: October 26 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
1.211 ! dtucker 277: (key derivation function, currently
! 278: .Xr bcrypt_pbkdf 3 )
! 279: rounds used.
1.117 djm 280: Higher numbers result in slower passphrase verification and increased
281: resistance to brute-force password cracking (should the keys be stolen).
1.204 dtucker 282: The default is 16 rounds.
1.66 jmc 283: .It Fl B
284: Show the bubblebabble digest of specified private or public key file.
1.2 deraadt 285: .It Fl b Ar bits
1.12 aaron 286: Specifies the number of bits in the key to create.
1.158 dtucker 287: For RSA keys, the minimum size is 1024 bits and the default is 3072 bits.
288: Generally, 3072 bits is considered sufficient.
1.72 dtucker 289: DSA keys must be exactly 1024 bits as specified by FIPS 186-2.
1.106 djm 290: For ECDSA keys, the
291: .Fl b
1.107 deraadt 292: flag determines the key length by selecting from one of three elliptic
1.106 djm 293: curve sizes: 256, 384 or 521 bits.
294: Attempting to use bit lengths other than these three values for ECDSA keys
295: will fail.
1.176 naddy 296: ECDSA-SK, Ed25519 and Ed25519-SK keys have a fixed length and the
1.118 naddy 297: .Fl b
298: flag will be ignored.
1.66 jmc 299: .It Fl C Ar comment
300: Provides a new comment.
1.2 deraadt 301: .It Fl c
1.1 deraadt 302: Requests changing the comment in the private and public key files.
303: The program will prompt for the file containing the private keys, for
1.41 stevesk 304: the passphrase if the key has one, and for the new comment.
1.81 markus 305: .It Fl D Ar pkcs11
1.157 naddy 306: Download the public keys provided by the PKCS#11 shared library
1.83 markus 307: .Ar pkcs11 .
1.98 djm 308: When used in combination with
309: .Fl s ,
310: this option indicates that a CA key resides in a PKCS#11 token (see the
311: .Sx CERTIFICATES
312: section for details).
1.124 djm 313: .It Fl E Ar fingerprint_hash
314: Specifies the hash algorithm used when displaying key fingerprints.
315: Valid options are:
316: .Dq md5
317: and
318: .Dq sha256 .
319: The default is
320: .Dq sha256 .
1.37 markus 321: .It Fl e
1.40 markus 322: This option will read a private or public OpenSSH key file and
1.154 djm 323: print to stdout a public key in one of the formats specified by the
1.95 djm 324: .Fl m
325: option.
326: The default export format is
327: .Dq RFC4716 .
1.96 jmc 328: This option allows exporting OpenSSH keys for use by other programs, including
1.95 djm 329: several commercial SSH implementations.
1.151 djm 330: .It Fl F Ar hostname | [hostname]:port
1.66 jmc 331: Search for the specified
332: .Ar hostname
1.151 djm 333: (with optional port number)
1.66 jmc 334: in a
335: .Pa known_hosts
336: file, listing any occurrences found.
337: This option is useful to find hashed host names or addresses and may also be
338: used in conjunction with the
339: .Fl H
340: option to print found keys in a hashed format.
341: .It Fl f Ar filename
342: Specifies the filename of the key file.
1.57 jakob 343: .It Fl g
1.62 jakob 344: Use generic DNS format when printing fingerprint resource records using the
1.63 jmc 345: .Fl r
1.62 jakob 346: command.
1.66 jmc 347: .It Fl H
348: Hash a
349: .Pa known_hosts
1.67 dtucker 350: file.
351: This replaces all hostnames and addresses with hashed representations
352: within the specified file; the original content is moved to a file with
353: a .old suffix.
1.66 jmc 354: These hashes may be used normally by
355: .Nm ssh
356: and
357: .Nm sshd ,
358: but they do not reveal identifying information should the file's contents
359: be disclosed.
360: This option will not modify existing hashed hostnames and is therefore safe
361: to use on files that mix hashed and non-hashed names.
1.84 djm 362: .It Fl h
363: When signing a key, create a host certificate instead of a user
364: certificate.
365: Please see the
366: .Sx CERTIFICATES
367: section for details.
1.85 jmc 368: .It Fl I Ar certificate_identity
1.84 djm 369: Specify the key identity when signing a public key.
370: Please see the
371: .Sx CERTIFICATES
372: section for details.
1.37 markus 373: .It Fl i
374: This option will read an unencrypted private (or public) key file
1.95 djm 375: in the format specified by the
376: .Fl m
377: option and print an OpenSSH compatible private
1.37 markus 378: (or public) key to stdout.
1.122 jmc 379: This option allows importing keys from other software, including several
380: commercial SSH implementations.
381: The default import format is
382: .Dq RFC4716 .
1.188 jmc 383: .It Fl K
1.187 djm 384: Download resident keys from a FIDO authenticator.
385: Public and private key files will be written to the current directory for
386: each downloaded key.
1.207 djm 387: If multiple FIDO authenticators are attached, keys will be downloaded from
388: the first touched authenticator.
1.111 djm 389: .It Fl k
390: Generate a KRL file.
391: In this mode,
392: .Nm
393: will generate a KRL file at the location specified via the
394: .Fl f
1.114 jmc 395: flag that revokes every key or certificate presented on the command line.
1.111 djm 396: Keys/certificates to be revoked may be specified by public key file or
397: using the format described in the
398: .Sx KEY REVOCATION LISTS
399: section.
1.86 djm 400: .It Fl L
1.129 djm 401: Prints the contents of one or more certificates.
1.9 markus 402: .It Fl l
1.77 grunk 403: Show fingerprint of specified public key file.
1.50 markus 404: For RSA and DSA keys
405: .Nm
1.78 jmc 406: tries to find the matching public key file and prints its fingerprint.
407: If combined with
408: .Fl v ,
1.132 jmc 409: a visual ASCII art representation of the key is supplied with the
1.131 djm 410: fingerprint.
1.184 djm 411: .It Fl M Cm generate
412: Generate candidate Diffie-Hellman Group Exchange (DH-GEX) parameters for
413: eventual use by the
414: .Sq diffie-hellman-group-exchange-*
415: key exchange methods.
416: The numbers generated by this operation must be further screened before
417: use.
418: See the
419: .Sx MODULI GENERATION
420: section for more information.
421: .It Fl M Cm screen
422: Screen candidate parameters for Diffie-Hellman Group Exchange.
423: This will accept a list of candidate numbers and test that they are
424: safe (Sophie Germain) primes with acceptable group generators.
425: The results of this operation may be added to the
426: .Pa /etc/moduli
427: file.
428: See the
429: .Sx MODULI GENERATION
430: section for more information.
1.95 djm 431: .It Fl m Ar key_format
1.155 djm 432: Specify a key format for key generation, the
1.95 djm 433: .Fl i
1.155 djm 434: (import),
1.95 djm 435: .Fl e
1.155 djm 436: (export) conversion options, and the
437: .Fl p
438: change passphrase operation.
439: The latter may be used to convert between OpenSSH private key and PEM
440: private key formats.
1.95 djm 441: The supported key formats are:
442: .Dq RFC4716
1.96 jmc 443: (RFC 4716/SSH2 public or private key),
1.95 djm 444: .Dq PKCS8
1.161 djm 445: (PKCS8 public or private key)
1.95 djm 446: or
447: .Dq PEM
448: (PEM public key).
1.161 djm 449: By default OpenSSH will write newly-generated private keys in its own
450: format, but when converting public keys for export the default format is
1.95 djm 451: .Dq RFC4716 .
1.148 djm 452: Setting a format of
453: .Dq PEM
454: when generating or updating a supported private key type will cause the
455: key to be stored in the legacy PEM private key format.
1.66 jmc 456: .It Fl N Ar new_passphrase
457: Provides the new passphrase.
1.84 djm 458: .It Fl n Ar principals
459: Specify one or more principals (user or host names) to be included in
460: a certificate when signing a key.
461: Multiple principals may be specified, separated by commas.
462: Please see the
463: .Sx CERTIFICATES
464: section for details.
1.93 djm 465: .It Fl O Ar option
1.184 djm 466: Specify a key/value option.
467: These are specific to the operation that
468: .Nm
469: has been requested to perform.
470: .Pp
471: When signing certificates, one of the options listed in the
1.183 djm 472: .Sx CERTIFICATES
1.184 djm 473: section may be specified here.
474: .Pp
475: When performing moduli generation or screening, one of the options
476: listed in the
477: .Sx MODULI GENERATION
478: section may be specified.
479: .Pp
1.190 jmc 480: When generating a key that will be hosted on a FIDO authenticator,
481: this flag may be used to specify key-specific options.
482: Those supported at present are:
483: .Bl -tag -width Ds
484: .It Cm application
485: Override the default FIDO application/origin string of
1.189 djm 486: .Dq ssh: .
1.190 jmc 487: This may be useful when generating host or domain-specific resident keys.
1.200 djm 488: The specified application string must begin with
489: .Dq ssh: .
1.199 jmc 490: .It Cm challenge Ns = Ns Ar path
1.198 jmc 491: Specifies a path to a challenge string that will be passed to the
492: FIDO token during key generation.
1.199 jmc 493: The challenge string may be used as part of an out-of-band
494: protocol for key enrollment
495: (a random challenge is used by default).
1.190 jmc 496: .It Cm device
497: Explicitly specify a
1.189 djm 498: .Xr fido 4
499: device to use, rather than letting the token middleware select one.
1.190 jmc 500: .It Cm no-touch-required
501: Indicate that the generated private key should not require touch
1.185 djm 502: events (user presence) when making signatures.
503: Note that
504: .Xr sshd 8
505: will refuse such signatures by default, unless overridden via
506: an authorized_keys option.
1.190 jmc 507: .It Cm resident
508: Indicate that the key should be stored on the FIDO authenticator itself.
1.185 djm 509: Resident keys may be supported on FIDO2 tokens and typically require that
510: a PIN be set on the token prior to generation.
511: Resident keys may be loaded off the token using
512: .Xr ssh-add 1 .
1.190 jmc 513: .It Cm user
514: A username to be associated with a resident key,
1.189 djm 515: overriding the empty default username.
516: Specifying a username may be useful when generating multiple resident keys
517: for the same application name.
1.206 djm 518: .It Cm verify-required
519: Indicate that this private key should require user verification for
520: each signature.
1.208 jmc 521: Not all FIDO tokens support this option.
1.206 djm 522: Currently PIN authentication is the only supported verification method,
523: but other methods may be supported in the future.
1.199 jmc 524: .It Cm write-attestation Ns = Ns Ar path
1.209 djm 525: May be used at key generation time to record the attestation data
1.197 djm 526: returned from FIDO tokens during key generation.
1.209 djm 527: Please note that this information is potentially sensitive.
528: By default, this information is discarded.
1.190 jmc 529: .El
1.185 djm 530: .Pp
531: The
532: .Fl O
533: option may be specified multiple times.
1.66 jmc 534: .It Fl P Ar passphrase
535: Provides the (old) passphrase.
1.2 deraadt 536: .It Fl p
1.1 deraadt 537: Requests changing the passphrase of a private key file instead of
1.12 aaron 538: creating a new private key.
539: The program will prompt for the file
1.1 deraadt 540: containing the private key, for the old passphrase, and twice for the
541: new passphrase.
1.113 jmc 542: .It Fl Q
543: Test whether keys have been revoked in a KRL.
1.203 djm 544: If the
545: .Fl l
546: option is also specified then the contents of the KRL will be printed.
1.5 aaron 547: .It Fl q
548: Silence
549: .Nm ssh-keygen .
1.152 djm 550: .It Fl R Ar hostname | [hostname]:port
1.151 djm 551: Removes all keys belonging to the specified
1.64 djm 552: .Ar hostname
1.151 djm 553: (with optional port number)
1.65 jmc 554: from a
1.64 djm 555: .Pa known_hosts
556: file.
1.65 jmc 557: This option is useful to delete hashed hosts (see the
1.64 djm 558: .Fl H
559: option above).
1.66 jmc 560: .It Fl r Ar hostname
561: Print the SSHFP fingerprint resource record named
562: .Ar hostname
563: for the specified public key file.
1.84 djm 564: .It Fl s Ar ca_key
565: Certify (sign) a public key using the specified CA key.
566: Please see the
567: .Sx CERTIFICATES
568: section for details.
1.111 djm 569: .Pp
570: When generating a KRL,
571: .Fl s
1.112 jmc 572: specifies a path to a CA public key file used to revoke certificates directly
1.111 djm 573: by key ID or serial number.
574: See the
575: .Sx KEY REVOCATION LISTS
576: section for details.
1.175 djm 577: .It Fl t Cm dsa | ecdsa | ecdsa-sk | ed25519 | ed25519-sk | rsa
1.66 jmc 578: Specifies the type of key to create.
579: The possible values are
1.100 naddy 580: .Dq dsa ,
1.118 naddy 581: .Dq ecdsa ,
1.173 naddy 582: .Dq ecdsa-sk ,
1.118 naddy 583: .Dq ed25519 ,
1.175 djm 584: .Dq ed25519-sk ,
1.100 naddy 585: or
1.139 jmc 586: .Dq rsa .
1.159 djm 587: .Pp
588: This flag may also be used to specify the desired signature type when
1.160 jmc 589: signing certificates using an RSA CA key.
1.159 djm 590: The available RSA signature variants are
591: .Dq ssh-rsa
592: (SHA1 signatures, not recommended),
1.160 jmc 593: .Dq rsa-sha2-256 ,
594: and
1.159 djm 595: .Dq rsa-sha2-512
596: (the default).
1.142 djm 597: .It Fl U
598: When used in combination with
599: .Fl s ,
600: this option indicates that a CA key resides in a
601: .Xr ssh-agent 1 .
602: See the
603: .Sx CERTIFICATES
604: section for more information.
1.112 jmc 605: .It Fl u
606: Update a KRL.
607: When specified with
608: .Fl k ,
1.114 jmc 609: keys listed via the command line are added to the existing KRL rather than
1.112 jmc 610: a new KRL being created.
1.84 djm 611: .It Fl V Ar validity_interval
612: Specify a validity interval when signing a certificate.
613: A validity interval may consist of a single time, indicating that the
614: certificate is valid beginning now and expiring at that time, or may consist
615: of two times separated by a colon to indicate an explicit time interval.
1.145 djm 616: .Pp
617: The start time may be specified as the string
618: .Dq always
619: to indicate the certificate has no specified start time,
1.147 djm 620: a date in YYYYMMDD format, a time in YYYYMMDDHHMM[SS] format,
1.145 djm 621: a relative time (to the current time) consisting of a minus sign followed by
622: an interval in the format described in the
1.116 jmc 623: TIME FORMATS section of
1.90 jmc 624: .Xr sshd_config 5 .
1.145 djm 625: .Pp
1.147 djm 626: The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMM[SS] time,
1.145 djm 627: a relative time starting with a plus character or the string
628: .Dq forever
1.202 dtucker 629: to indicate that the certificate has no expiry date.
1.84 djm 630: .Pp
631: For example:
632: .Dq +52w1d
633: (valid from now to 52 weeks and one day from now),
634: .Dq -4w:+4w
635: (valid from four weeks ago to four weeks from now),
636: .Dq 20100101123000:20110101123000
637: (valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011),
638: .Dq -1d:20110101
1.210 dtucker 639: (valid from yesterday to midnight, January 1st, 2011),
1.145 djm 640: .Dq -1m:forever
641: (valid from one minute ago and never expiring).
1.61 djm 642: .It Fl v
643: Verbose mode.
644: Causes
645: .Nm
646: to print debugging messages about its progress.
647: This is helpful for debugging moduli generation.
648: Multiple
649: .Fl v
650: options increase the verbosity.
651: The maximum is 3.
1.173 naddy 652: .It Fl w Ar provider
1.180 naddy 653: Specifies a path to a library that will be used when creating
654: FIDO authenticator-hosted keys, overriding the default of using
655: the internal USB HID support.
1.196 djm 656: .It Fl Y Cm find-principals
657: Find the principal(s) associated with the public key of a signature,
1.194 djm 658: provided using the
659: .Fl s
660: flag in an authorized signers file provided using the
661: .Fl f
662: flag.
663: The format of the allowed signers file is documented in the
664: .Sx ALLOWED SIGNERS
1.195 jmc 665: section below.
1.196 djm 666: If one or more matching principals are found, they are returned on
667: standard output.
1.182 jmc 668: .It Fl Y Cm check-novalidate
669: Checks that a signature generated using
670: .Nm
671: .Fl Y Cm sign
672: has a valid structure.
673: This does not validate if a signature comes from an authorized signer.
674: When testing a signature,
675: .Nm
676: accepts a message on standard input and a signature namespace using
677: .Fl n .
678: A file containing the corresponding signature must also be supplied using the
679: .Fl s
680: flag.
681: Successful testing of the signature is signalled by
682: .Nm
683: returning a zero exit status.
1.166 jmc 684: .It Fl Y Cm sign
1.163 djm 685: Cryptographically sign a file or some data using a SSH key.
686: When signing,
687: .Nm
688: accepts zero or more files to sign on the command-line - if no files
689: are specified then
690: .Nm
691: will sign data presented on standard input.
692: Signatures are written to the path of the input file with
693: .Dq .sig
694: appended, or to standard output if the message to be signed was read from
695: standard input.
696: .Pp
697: The key used for signing is specified using the
698: .Fl f
699: option and may refer to either a private key, or a public key with the private
700: half available via
701: .Xr ssh-agent 1 .
702: An additional signature namespace, used to prevent signature confusion across
703: different domains of use (e.g. file signing vs email signing) must be provided
704: via the
705: .Fl n
706: flag.
707: Namespaces are arbitrary strings, and may include:
708: .Dq file
709: for file signing,
710: .Dq email
711: for email signing.
712: For custom uses, it is recommended to use names following a
713: NAMESPACE@YOUR.DOMAIN pattern to generate unambiguous namespaces.
1.166 jmc 714: .It Fl Y Cm verify
1.163 djm 715: Request to verify a signature generated using
716: .Nm
1.166 jmc 717: .Fl Y Cm sign
1.163 djm 718: as described above.
719: When verifying a signature,
720: .Nm
721: accepts a message on standard input and a signature namespace using
722: .Fl n .
723: A file containing the corresponding signature must also be supplied using the
724: .Fl s
725: flag, along with the identity of the signer using
726: .Fl I
727: and a list of allowed signers via the
728: .Fl f
729: flag.
730: The format of the allowed signers file is documented in the
731: .Sx ALLOWED SIGNERS
732: section below.
733: A file containing revoked keys can be passed using the
734: .Fl r
1.165 jmc 735: flag.
736: The revocation file may be a KRL or a one-per-line list of public keys.
1.163 djm 737: Successful verification by an authorized signer is signalled by
738: .Nm
739: returning a zero exit status.
1.181 jmc 740: .It Fl y
741: This option will read a private
742: OpenSSH format file and print an OpenSSH public key to stdout.
1.93 djm 743: .It Fl z Ar serial_number
744: Specifies a serial number to be embedded in the certificate to distinguish
745: this certificate from others from the same CA.
1.156 djm 746: If the
747: .Ar serial_number
748: is prefixed with a
749: .Sq +
750: character, then the serial number will be incremented for each certificate
751: signed on a single command-line.
1.93 djm 752: The default serial number is zero.
1.111 djm 753: .Pp
754: When generating a KRL, the
755: .Fl z
756: flag is used to specify a KRL version number.
1.2 deraadt 757: .El
1.60 djm 758: .Sh MODULI GENERATION
759: .Nm
760: may be used to generate groups for the Diffie-Hellman Group Exchange
761: (DH-GEX) protocol.
762: Generating these groups is a two-step process: first, candidate
763: primes are generated using a fast, but memory intensive process.
764: These candidate primes are then tested for suitability (a CPU-intensive
765: process).
766: .Pp
767: Generation of primes is performed using the
1.184 djm 768: .Fl M Cm generate
1.60 djm 769: option.
770: The desired length of the primes may be specified by the
1.184 djm 771: .Fl O Cm bits
1.60 djm 772: option.
773: For example:
774: .Pp
1.184 djm 775: .Dl # ssh-keygen -M generate -O bits=2048 moduli-2048.candidates
1.60 djm 776: .Pp
777: By default, the search for primes begins at a random point in the
778: desired length range.
779: This may be overridden using the
1.184 djm 780: .Fl O Cm start
1.60 djm 781: option, which specifies a different start point (in hex).
782: .Pp
1.109 dtucker 783: Once a set of candidates have been generated, they must be screened for
1.60 djm 784: suitability.
785: This may be performed using the
1.184 djm 786: .Fl M Cm screen
1.60 djm 787: option.
788: In this mode
789: .Nm
790: will read candidates from standard input (or a file specified using the
791: .Fl f
792: option).
793: For example:
794: .Pp
1.184 djm 795: .Dl # ssh-keygen -M screen -f moduli-2048.candidates moduli-2048
1.60 djm 796: .Pp
797: By default, each candidate will be subjected to 100 primality tests.
798: This may be overridden using the
1.184 djm 799: .Fl O Cm prime-tests
1.60 djm 800: option.
801: The DH generator value will be chosen automatically for the
802: prime under consideration.
803: If a specific generator is desired, it may be requested using the
1.184 djm 804: .Fl O Cm generator
1.60 djm 805: option.
1.66 jmc 806: Valid generator values are 2, 3, and 5.
1.60 djm 807: .Pp
808: Screened DH groups may be installed in
809: .Pa /etc/moduli .
810: It is important that this file contains moduli of a range of bit lengths and
811: that both ends of a connection share common moduli.
1.184 djm 812: .Pp
813: A number of options are available for moduli generation and screening via the
814: .Fl O
815: flag:
1.186 jmc 816: .Bl -tag -width Ds
1.184 djm 817: .It Ic lines Ns = Ns Ar number
818: Exit after screening the specified number of lines while performing DH
819: candidate screening.
820: .It Ic start-line Ns = Ns Ar line-number
821: Start screening at the specified line number while performing DH candidate
822: screening.
823: .It Ic checkpoint Ns = Ns Ar filename
824: Write the last line processed to the specified file while performing DH
825: candidate screening.
826: This will be used to skip lines in the input file that have already been
827: processed if the job is restarted.
828: .It Ic memory Ns = Ns Ar mbytes
829: Specify the amount of memory to use (in megabytes) when generating
830: candidate moduli for DH-GEX.
831: .It Ic start Ns = Ns Ar hex-value
832: Specify start point (in hex) when generating candidate moduli for DH-GEX.
833: .It Ic generator Ns = Ns Ar value
834: Specify desired generator (in decimal) when testing candidate moduli for DH-GEX.
835: .El
1.84 djm 836: .Sh CERTIFICATES
837: .Nm
838: supports signing of keys to produce certificates that may be used for
839: user or host authentication.
840: Certificates consist of a public key, some identity information, zero or
1.94 jmc 841: more principal (user or host) names and a set of options that
1.84 djm 842: are signed by a Certification Authority (CA) key.
843: Clients or servers may then trust only the CA key and verify its signature
844: on a certificate rather than trusting many user/host keys.
845: Note that OpenSSH certificates are a different, and much simpler, format to
846: the X.509 certificates used in
847: .Xr ssl 8 .
848: .Pp
849: .Nm
850: supports two types of certificates: user and host.
851: User certificates authenticate users to servers, whereas host certificates
1.85 jmc 852: authenticate server hosts to users.
853: To generate a user certificate:
1.84 djm 854: .Pp
855: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
856: .Pp
857: The resultant certificate will be placed in
1.91 djm 858: .Pa /path/to/user_key-cert.pub .
1.84 djm 859: A host certificate requires the
860: .Fl h
861: option:
862: .Pp
863: .Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
864: .Pp
865: The host certificate will be output to
1.91 djm 866: .Pa /path/to/host_key-cert.pub .
1.98 djm 867: .Pp
868: It is possible to sign using a CA key stored in a PKCS#11 token by
869: providing the token library using
870: .Fl D
871: and identifying the CA key by providing its public half as an argument
872: to
873: .Fl s :
874: .Pp
1.127 naddy 875: .Dl $ ssh-keygen -s ca_key.pub -D libpkcs11.so -I key_id user_key.pub
1.142 djm 876: .Pp
877: Similarly, it is possible for the CA key to be hosted in a
878: .Xr ssh-agent 1 .
879: This is indicated by the
880: .Fl U
881: flag and, again, the CA key must be identified by its public half.
882: .Pp
883: .Dl $ ssh-keygen -Us ca_key.pub -I key_id user_key.pub
1.98 djm 884: .Pp
885: In all cases,
1.84 djm 886: .Ar key_id
887: is a "key identifier" that is logged by the server when the certificate
888: is used for authentication.
889: .Pp
890: Certificates may be limited to be valid for a set of principal (user/host)
891: names.
892: By default, generated certificates are valid for all users or hosts.
893: To generate a certificate for a specified set of principals:
894: .Pp
895: .Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
1.127 naddy 896: .Dl "$ ssh-keygen -s ca_key -I key_id -h -n host.domain host_key.pub"
1.84 djm 897: .Pp
898: Additional limitations on the validity and use of user certificates may
1.94 jmc 899: be specified through certificate options.
1.93 djm 900: A certificate option may disable features of the SSH session, may be
1.84 djm 901: valid only when presented from particular source addresses or may
902: force the use of a specific command.
1.183 djm 903: .Pp
904: The options that are valid for user certificates are:
905: .Pp
906: .Bl -tag -width Ds -compact
907: .It Ic clear
908: Clear all enabled permissions.
909: This is useful for clearing the default set of permissions so permissions may
910: be added individually.
911: .Pp
912: .It Ic critical : Ns Ar name Ns Op Ns = Ns Ar contents
913: .It Ic extension : Ns Ar name Ns Op Ns = Ns Ar contents
914: Includes an arbitrary certificate critical option or extension.
915: The specified
916: .Ar name
917: should include a domain suffix, e.g.\&
918: .Dq name@example.com .
919: If
920: .Ar contents
921: is specified then it is included as the contents of the extension/option
922: encoded as a string, otherwise the extension/option is created with no
923: contents (usually indicating a flag).
924: Extensions may be ignored by a client or server that does not recognise them,
925: whereas unknown critical options will cause the certificate to be refused.
926: .Pp
927: .It Ic force-command Ns = Ns Ar command
928: Forces the execution of
929: .Ar command
930: instead of any shell or command specified by the user when
931: the certificate is used for authentication.
932: .Pp
933: .It Ic no-agent-forwarding
934: Disable
935: .Xr ssh-agent 1
936: forwarding (permitted by default).
937: .Pp
938: .It Ic no-port-forwarding
939: Disable port forwarding (permitted by default).
940: .Pp
941: .It Ic no-pty
942: Disable PTY allocation (permitted by default).
943: .Pp
944: .It Ic no-user-rc
945: Disable execution of
946: .Pa ~/.ssh/rc
947: by
948: .Xr sshd 8
949: (permitted by default).
950: .Pp
951: .It Ic no-x11-forwarding
952: Disable X11 forwarding (permitted by default).
953: .Pp
954: .It Ic permit-agent-forwarding
955: Allows
956: .Xr ssh-agent 1
957: forwarding.
958: .Pp
959: .It Ic permit-port-forwarding
960: Allows port forwarding.
961: .Pp
962: .It Ic permit-pty
963: Allows PTY allocation.
964: .Pp
965: .It Ic permit-user-rc
966: Allows execution of
967: .Pa ~/.ssh/rc
968: by
969: .Xr sshd 8 .
970: .Pp
971: .It Ic permit-X11-forwarding
972: Allows X11 forwarding.
973: .Pp
974: .It Ic no-touch-required
1.206 djm 975: Do not require signatures made using this key include demonstration
1.193 naddy 976: of user presence (e.g. by having the user touch the authenticator).
1.192 naddy 977: This option only makes sense for the FIDO authenticator algorithms
1.183 djm 978: .Cm ecdsa-sk
979: and
980: .Cm ed25519-sk .
981: .Pp
982: .It Ic source-address Ns = Ns Ar address_list
983: Restrict the source addresses from which the certificate is considered valid.
984: The
985: .Ar address_list
986: is a comma-separated list of one or more address/netmask pairs in CIDR
987: format.
1.206 djm 988: .Pp
989: .It Ic verify-required
990: Require signatures made using this key indicate that the user was first
991: verified.
992: This option only makes sense for the FIDO authenticator algorithms
993: .Cm ecdsa-sk
994: and
995: .Cm ed25519-sk .
996: Currently PIN authentication is the only supported verification method,
997: but other methods may be supported in the future.
1.183 djm 998: .El
999: .Pp
1000: At present, no standard options are valid for host keys.
1.84 djm 1001: .Pp
1002: Finally, certificates may be defined with a validity lifetime.
1003: The
1004: .Fl V
1005: option allows specification of certificate start and end times.
1006: A certificate that is presented at a time outside this range will not be
1007: considered valid.
1.210 dtucker 1008: By default, certificates are valid from the
1.110 jmc 1009: .Ux
1010: Epoch to the distant future.
1.84 djm 1011: .Pp
1012: For certificates to be used for user or host authentication, the CA
1013: public key must be trusted by
1014: .Xr sshd 8
1015: or
1016: .Xr ssh 1 .
1017: Please refer to those manual pages for details.
1.111 djm 1018: .Sh KEY REVOCATION LISTS
1019: .Nm
1020: is able to manage OpenSSH format Key Revocation Lists (KRLs).
1021: These binary files specify keys or certificates to be revoked using a
1.119 tedu 1022: compact format, taking as little as one bit per certificate if they are being
1.111 djm 1023: revoked by serial number.
1024: .Pp
1025: KRLs may be generated using the
1026: .Fl k
1027: flag.
1.114 jmc 1028: This option reads one or more files from the command line and generates a new
1.111 djm 1029: KRL.
1030: The files may either contain a KRL specification (see below) or public keys,
1031: listed one per line.
1032: Plain public keys are revoked by listing their hash or contents in the KRL and
1033: certificates revoked by serial number or key ID (if the serial is zero or
1034: not available).
1035: .Pp
1036: Revoking keys using a KRL specification offers explicit control over the
1037: types of record used to revoke keys and may be used to directly revoke
1038: certificates by serial number or key ID without having the complete original
1039: certificate on hand.
1040: A KRL specification consists of lines containing one of the following directives
1041: followed by a colon and some directive-specific information.
1042: .Bl -tag -width Ds
1.115 jmc 1043: .It Cm serial : Ar serial_number Ns Op - Ns Ar serial_number
1.111 djm 1044: Revokes a certificate with the specified serial number.
1.112 jmc 1045: Serial numbers are 64-bit values, not including zero and may be expressed
1.111 djm 1046: in decimal, hex or octal.
1047: If two serial numbers are specified separated by a hyphen, then the range
1048: of serial numbers including and between each is revoked.
1049: The CA key must have been specified on the
1050: .Nm
1.114 jmc 1051: command line using the
1.111 djm 1052: .Fl s
1053: option.
1054: .It Cm id : Ar key_id
1055: Revokes a certificate with the specified key ID string.
1056: The CA key must have been specified on the
1057: .Nm
1.114 jmc 1058: command line using the
1.111 djm 1059: .Fl s
1060: option.
1061: .It Cm key : Ar public_key
1062: Revokes the specified key.
1.112 jmc 1063: If a certificate is listed, then it is revoked as a plain public key.
1.111 djm 1064: .It Cm sha1 : Ar public_key
1.149 djm 1065: Revokes the specified key by including its SHA1 hash in the KRL.
1066: .It Cm sha256 : Ar public_key
1067: Revokes the specified key by including its SHA256 hash in the KRL.
1068: KRLs that revoke keys by SHA256 hash are not supported by OpenSSH versions
1069: prior to 7.9.
1070: .It Cm hash : Ar fingerprint
1.150 djm 1071: Revokes a key using a fingerprint hash, as obtained from a
1.149 djm 1072: .Xr sshd 8
1073: authentication log message or the
1074: .Nm
1075: .Fl l
1076: flag.
1077: Only SHA256 fingerprints are supported here and resultant KRLs are
1078: not supported by OpenSSH versions prior to 7.9.
1.111 djm 1079: .El
1080: .Pp
1081: KRLs may be updated using the
1082: .Fl u
1083: flag in addition to
1084: .Fl k .
1.114 jmc 1085: When this option is specified, keys listed via the command line are merged into
1.111 djm 1086: the KRL, adding to those already there.
1087: .Pp
1088: It is also possible, given a KRL, to test whether it revokes a particular key
1089: (or keys).
1090: The
1091: .Fl Q
1.128 jmc 1092: flag will query an existing KRL, testing each key specified on the command line.
1.114 jmc 1093: If any key listed on the command line has been revoked (or an error encountered)
1.111 djm 1094: then
1095: .Nm
1096: will exit with a non-zero exit status.
1097: A zero exit status will only be returned if no key was revoked.
1.163 djm 1098: .Sh ALLOWED SIGNERS
1099: When verifying signatures,
1100: .Nm
1101: uses a simple list of identities and keys to determine whether a signature
1102: comes from an authorized source.
1103: This "allowed signers" file uses a format patterned after the
1104: AUTHORIZED_KEYS FILE FORMAT described in
1.165 jmc 1105: .Xr sshd 8 .
1.163 djm 1106: Each line of the file contains the following space-separated fields:
1107: principals, options, keytype, base64-encoded key.
1108: Empty lines and lines starting with a
1109: .Ql #
1110: are ignored as comments.
1111: .Pp
1.210 dtucker 1112: The principals field is a pattern-list (see PATTERNS in
1.163 djm 1113: .Xr ssh_config 5 )
1114: consisting of one or more comma-separated USER@DOMAIN identity patterns
1115: that are accepted for signing.
1116: When verifying, the identity presented via the
1.172 jmc 1117: .Fl I
1118: option must match a principals pattern in order for the corresponding key to be
1.163 djm 1119: considered acceptable for verification.
1120: .Pp
1121: The options (if present) consist of comma-separated option specifications.
1122: No spaces are permitted, except within double quotes.
1123: The following option specifications are supported (note that option keywords
1124: are case-insensitive):
1125: .Bl -tag -width Ds
1126: .It Cm cert-authority
1127: Indicates that this key is accepted as a certificate authority (CA) and
1128: that certificates signed by this CA may be accepted for verification.
1129: .It Cm namespaces="namespace-list"
1130: Specifies a pattern-list of namespaces that are accepted for this key.
1.164 djm 1131: If this option is present, the signature namespace embedded in the
1.163 djm 1132: signature object and presented on the verification command-line must
1133: match the specified list before the key will be considered acceptable.
1134: .El
1135: .Pp
1136: When verifying signatures made by certificates, the expected principal
1137: name must match both the principals pattern in the allowed signers file and
1138: the principals embedded in the certificate itself.
1139: .Pp
1140: An example allowed signers file:
1141: .Bd -literal -offset 3n
1142: # Comments allowed at start of line
1143: user1@example.com,user2@example.com ssh-rsa AAAAX1...
1144: # A certificate authority, trusted for all principals in a domain.
1145: *@example.com cert-authority ssh-ed25519 AAAB4...
1146: # A key that is accepted only for file signing.
1147: user2@example.com namespaces="file" ssh-ed25519 AAA41...
1148: .Ed
1.173 naddy 1149: .Sh ENVIRONMENT
1150: .Bl -tag -width Ds
1151: .It Ev SSH_SK_PROVIDER
1.201 djm 1152: Specifies a path to a library that will be used when loading any
1153: FIDO authenticator-hosted keys, overriding the default of using
1154: the built-in USB HID support.
1.173 naddy 1155: .El
1.2 deraadt 1156: .Sh FILES
1.100 naddy 1157: .Bl -tag -width Ds -compact
1.68 djm 1158: .It Pa ~/.ssh/id_dsa
1.100 naddy 1159: .It Pa ~/.ssh/id_ecdsa
1.173 naddy 1160: .It Pa ~/.ssh/id_ecdsa_sk
1.118 naddy 1161: .It Pa ~/.ssh/id_ed25519
1.176 naddy 1162: .It Pa ~/.ssh/id_ed25519_sk
1.100 naddy 1163: .It Pa ~/.ssh/id_rsa
1.180 naddy 1164: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1165: authenticator-hosted Ed25519 or RSA authentication identity of the user.
1.15 deraadt 1166: This file should not be readable by anyone but the user.
1167: It is possible to
1168: specify a passphrase when generating the key; that passphrase will be
1.80 dtucker 1169: used to encrypt the private part of this file using 128-bit AES.
1.15 deraadt 1170: This file is not automatically accessed by
1171: .Nm
1172: but it is offered as the default file for the private key.
1.46 markus 1173: .Xr ssh 1
1.15 deraadt 1174: will read this file when a login attempt is made.
1.100 naddy 1175: .Pp
1.68 djm 1176: .It Pa ~/.ssh/id_dsa.pub
1.100 naddy 1177: .It Pa ~/.ssh/id_ecdsa.pub
1.173 naddy 1178: .It Pa ~/.ssh/id_ecdsa_sk.pub
1.118 naddy 1179: .It Pa ~/.ssh/id_ed25519.pub
1.176 naddy 1180: .It Pa ~/.ssh/id_ed25519_sk.pub
1.68 djm 1181: .It Pa ~/.ssh/id_rsa.pub
1.180 naddy 1182: Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
1183: authenticator-hosted Ed25519 or RSA public key for authentication.
1.15 deraadt 1184: The contents of this file should be added to
1.68 djm 1185: .Pa ~/.ssh/authorized_keys
1.15 deraadt 1186: on all machines
1.49 deraadt 1187: where the user wishes to log in using public key authentication.
1.12 aaron 1188: There is no need to keep the contents of this file secret.
1.100 naddy 1189: .Pp
1.60 djm 1190: .It Pa /etc/moduli
1191: Contains Diffie-Hellman groups used for DH-GEX.
1192: The file format is described in
1193: .Xr moduli 5 .
1.19 aaron 1194: .El
1.2 deraadt 1195: .Sh SEE ALSO
1196: .Xr ssh 1 ,
1197: .Xr ssh-add 1 ,
1.8 ericj 1198: .Xr ssh-agent 1 ,
1.60 djm 1199: .Xr moduli 5 ,
1.30 itojun 1200: .Xr sshd 8
1.37 markus 1201: .Rs
1.73 markus 1202: .%R RFC 4716
1203: .%T "The Secure Shell (SSH) Public Key File Format"
1204: .%D 2006
1.37 markus 1205: .Re
1.59 jmc 1206: .Sh AUTHORS
1207: OpenSSH is a derivative of the original and free
1208: ssh 1.2.12 release by Tatu Ylonen.
1209: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
1210: Theo de Raadt and Dug Song
1211: removed many bugs, re-added newer features and
1212: created OpenSSH.
1213: Markus Friedl contributed the support for SSH
1214: protocol versions 1.5 and 2.0.
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