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1 .Dd June 23 2020 2 .Dt NTP_KEYGEN 1ntp-keygenmdoc User Commands 3 .Os 4 .\" EDIT THIS FILE WITH CAUTION (ntp-keygen-opts.mdoc) 5 .\" 6 .\" It has been AutoGen-ed June 23, 2020 at 02:21:05 AM by AutoGen 5.18.5 7 .\" From the definitions ntp-keygen-opts.def 8 .\" and the template file agmdoc-cmd.tpl 9 .Sh NAME 10 .Nm ntp-keygen 11 .Nd Create a NTP host key 12 .Sh SYNOPSIS 13 .Nm 14 .\" Mixture of short (flag) options and long options 15 .Op Fl flags 16 .Op Fl flag Op Ar value 17 .Op Fl \-option\-name Ns Oo Oo Ns "=| " Oc Ns Ar value Oc 18 .Pp 19 All arguments must be options. 20 .Pp 21 .Sh DESCRIPTION 22 This program generates cryptographic data files used by the NTPv4 23 authentication and identification schemes. 24 It can generate message digest keys used in symmetric key cryptography and, 25 if the OpenSSL software library has been installed, it can generate host keys, 26 signing keys, certificates, and identity keys and parameters used in Autokey 27 public key cryptography. 28 These files are used for cookie encryption, 29 digital signature, and challenge/response identification algorithms 30 compatible with the Internet standard security infrastructure. 31 .Pp 32 The message digest symmetric keys file is generated in a format 33 compatible with NTPv3. 34 All other files are in PEM\-encoded printable ASCII format, 35 so they can be embedded as MIME attachments in email to other sites 36 and certificate authorities. 37 By default, files are not encrypted. 38 .Pp 39 When used to generate message digest symmetric keys, the program 40 produces a file containing ten pseudo\-random printable ASCII strings 41 suitable for the MD5 message digest algorithm included in the 42 distribution. 43 If the OpenSSL library is installed, it produces an additional ten 44 hex\-encoded random bit strings suitable for SHA1, AES\-128\-CMAC, and 45 other message digest algorithms. 46 The message digest symmetric keys file must be distributed and stored 47 using secure means beyond the scope of NTP itself. 48 Besides the keys used for ordinary NTP associations, additional keys 49 can be defined as passwords for the 50 .Xr ntpq 1ntpqmdoc 51 and 52 .Xr ntpdc 1ntpdcmdoc 53 utility programs. 54 .Pp 55 The remaining generated files are compatible with other OpenSSL 56 applications and other Public Key Infrastructure (PKI) resources. 57 Certificates generated by this program are compatible with extant 58 industry practice, although some users might find the interpretation of 59 X509v3 extension fields somewhat liberal. 60 However, the identity keys are probably not compatible with anything 61 other than Autokey. 62 .Pp 63 Some files used by this program are encrypted using a private password. 64 The 65 .Fl p 66 option specifies the read password for local encrypted files and the 67 .Fl q 68 option the write password for encrypted files sent to remote sites. 69 If no password is specified, the host name returned by the Unix 70 .Xr hostname 1 71 command, normally the DNS name of the host, is used as the the default read 72 password, for convenience. 73 The 74 .Nm 75 program prompts for the password if it reads an encrypted file 76 and the password is missing or incorrect. 77 If an encrypted file is read successfully and 78 no write password is specified, the read password is used 79 as the write password by default. 80 .Pp 81 The 82 .Cm pw 83 option of the 84 .Ic crypto 85 .Xr ntpd 1ntpdmdoc 86 configuration command specifies the read 87 password for previously encrypted local files. 88 This must match the local read password used by this program. 89 If not specified, the host name is used. 90 Thus, if files are generated by this program without an explicit password, 91 they can be read back by 92 .Xr ntpd 1ntpdmdoc 93 without specifying an explicit password but only on the same host. 94 If the write password used for encryption is specified as the host name, 95 these files can be read by that host with no explicit password. 96 .Pp 97 Normally, encrypted files for each host are generated by that host and 98 used only by that host, although exceptions exist as noted later on 99 this page. 100 The symmetric keys file, normally called 101 .Pa ntp.keys , 102 is usually installed in 103 .Pa /etc . 104 Other files and links are usually installed in 105 .Pa /usr/local/etc , 106 which is normally in a shared filesystem in 107 NFS\-mounted networks and cannot be changed by shared clients. 108 In these cases, NFS clients can specify the files in another 109 directory such as 110 .Pa /etc 111 using the 112 .Ic keysdir 113 .Xr ntpd 1ntpdmdoc 114 configuration file command. 115 .Pp 116 This program directs commentary and error messages to the standard 117 error stream 118 .Pa stderr 119 and remote files to the standard output stream 120 .Pa stdout 121 where they can be piped to other applications or redirected to files. 122 The names used for generated files and links all begin with the 123 string 124 .Pa ntpkey\&* 125 and include the file type, generating host and filestamp, 126 as described in the 127 .Sx "Cryptographic Data Files" 128 section below. 129 .Ss Running the Program 130 The safest way to run the 131 .Nm 132 program is logged in directly as root. 133 The recommended procedure is change to the 134 .Ar keys 135 directory, usually 136 .Pa /usr/local/etc , 137 then run the program. 138 .Pp 139 To test and gain experience with Autokey concepts, log in as root and 140 change to the 141 .Ar keys 142 directory, usually 143 .Pa /usr/local/etc . 144 When run for the first time, or if all files with names beginning with 145 .Pa ntpkey\&* 146 have been removed, use the 147 .Nm 148 command without arguments to generate a default 149 .Cm RSA 150 host key and matching 151 .Cm RSA\-MD5 152 certificate file with expiration date one year hence, 153 which is all that is necessary in many cases. 154 The program also generates soft links from the generic names 155 to the respective files. 156 If run again without options, the program uses the 157 existing keys and parameters and generates a new certificate file with 158 new expiration date one year hence, and soft link. 159 .Pp 160 The host key is used to encrypt the cookie when required and so must be 161 .Cm RSA 162 type. 163 By default, the host key is also the sign key used to encrypt signatures. 164 When necessary, a different sign key can be specified and this can be 165 either 166 .Cm RSA 167 or 168 .Cm DSA 169 type. 170 By default, the message digest type is 171 .Cm MD5 , 172 but any combination 173 of sign key type and message digest type supported by the OpenSSL library 174 can be specified, including those using the 175 .Cm AES128CMAC , MD2 , MD5 , MDC2 , SHA , SHA1 176 and 177 .Cm RIPE160 178 message digest algorithms. 179 However, the scheme specified in the certificate must be compatible 180 with the sign key. 181 Certificates using any digest algorithm are compatible with 182 .Cm RSA 183 sign keys; 184 however, only 185 .Cm SHA 186 and 187 .Cm SHA1 188 certificates are compatible with 189 .Cm DSA 190 sign keys. 191 .Pp 192 Private/public key files and certificates are compatible with 193 other OpenSSL applications and very likely other libraries as well. 194 Certificates or certificate requests derived from them should be compatible 195 with extant industry practice, although some users might find 196 the interpretation of X509v3 extension fields somewhat liberal. 197 However, the identification parameter files, although encoded 198 as the other files, are probably not compatible with anything other than Autokey. 199 .Pp 200 Running the program as other than root and using the Unix 201 .Xr su 1 202 command 203 to assume root may not work properly, since by default the OpenSSL library 204 looks for the random seed file 205 .Pa .rnd 206 in the user home directory. 207 However, there should be only one 208 .Pa .rnd , 209 most conveniently 210 in the root directory, so it is convenient to define the 211 .Ev RANDFILE 212 environment variable used by the OpenSSL library as the path to 213 .Pa .rnd . 214 .Pp 215 Installing the keys as root might not work in NFS\-mounted 216 shared file systems, as NFS clients may not be able to write 217 to the shared keys directory, even as root. 218 In this case, NFS clients can specify the files in another 219 directory such as 220 .Pa /etc 221 using the 222 .Ic keysdir 223 .Xr ntpd 1ntpdmdoc 224 configuration file command. 225 There is no need for one client to read the keys and certificates 226 of other clients or servers, as these data are obtained automatically 227 by the Autokey protocol. 228 .Pp 229 Ordinarily, cryptographic files are generated by the host that uses them, 230 but it is possible for a trusted agent (TA) to generate these files 231 for other hosts; however, in such cases files should always be encrypted. 232 The subject name and trusted name default to the hostname 233 of the host generating the files, but can be changed by command line options. 234 It is convenient to designate the owner name and trusted name 235 as the subject and issuer fields, respectively, of the certificate. 236 The owner name is also used for the host and sign key files, 237 while the trusted name is used for the identity files. 238 .Pp 239 All files are installed by default in the keys directory 240 .Pa /usr/local/etc , 241 which is normally in a shared filesystem 242 in NFS\-mounted networks. 243 The actual location of the keys directory 244 and each file can be overridden by configuration commands, 245 but this is not recommended. 246 Normally, the files for each host are generated by that host 247 and used only by that host, although exceptions exist 248 as noted later on this page. 249 .Pp 250 Normally, files containing private values, 251 including the host key, sign key and identification parameters, 252 are permitted root read/write\-only; 253 while others containing public values are permitted world readable. 254 Alternatively, files containing private values can be encrypted 255 and these files permitted world readable, 256 which simplifies maintenance in shared file systems. 257 Since uniqueness is insured by the 258 .Ar hostname 259 and 260 .Ar filestamp 261 file name extensions, the files for an NTP server and 262 dependent clients can all be installed in the same shared directory. 263 .Pp 264 The recommended practice is to keep the file name extensions 265 when installing a file and to install a soft link 266 from the generic names specified elsewhere on this page 267 to the generated files. 268 This allows new file generations to be activated simply 269 by changing the link. 270 If a link is present, 271 .Xr ntpd 1ntpdmdoc 272 follows it to the file name to extract the 273 .Ar filestamp . 274 If a link is not present, 275 .Xr ntpd 1ntpdmdoc 276 extracts the 277 .Ar filestamp 278 from the file itself. 279 This allows clients to verify that the file and generation times 280 are always current. 281 The 282 .Nm 283 program uses the same 284 .Ar filestamp 285 extension for all files generated 286 at one time, so each generation is distinct and can be readily 287 recognized in monitoring data. 288 .Pp 289 Run the command on as many hosts as necessary. 290 Designate one of them as the trusted host (TH) using 291 .Nm 292 with the 293 .Fl T 294 option and configure it to synchronize from reliable Internet servers. 295 Then configure the other hosts to synchronize to the TH directly or 296 indirectly. 297 A certificate trail is created when Autokey asks the immediately 298 ascendant host towards the TH to sign its certificate, which is then 299 provided to the immediately descendant host on request. 300 All group hosts should have acyclic certificate trails ending on the TH. 301 .Pp 302 The host key is used to encrypt the cookie when required and so must be 303 RSA type. 304 By default, the host key is also the sign key used to encrypt 305 signatures. 306 A different sign key can be assigned using the 307 .Fl S 308 option and this can be either 309 .Cm RSA 310 or 311 .Cm DSA 312 type. 313 By default, the signature 314 message digest type is 315 .Cm MD5 , 316 but any combination of sign key type and 317 message digest type supported by the OpenSSL library can be specified 318 using the 319 .Fl c 320 option. 321 .Pp 322 The rules say cryptographic media should be generated with proventic 323 filestamps, which means the host should already be synchronized before 324 this program is run. 325 This of course creates a chicken\-and\-egg problem 326 when the host is started for the first time. 327 Accordingly, the host time 328 should be set by some other means, such as eyeball\-and\-wristwatch, at 329 least so that the certificate lifetime is within the current year. 330 After that and when the host is synchronized to a proventic source, the 331 certificate should be re\-generated. 332 .Pp 333 Additional information on trusted groups and identity schemes is on the 334 .Dq Autokey Public\-Key Authentication 335 page. 336 .Pp 337 File names begin with the prefix 338 .Pa ntpkey Ns _ 339 and end with the suffix 340 .Pa _ Ns Ar hostname . Ar filestamp , 341 where 342 .Ar hostname 343 is the owner name, usually the string returned 344 by the Unix 345 .Xr hostname 1 346 command, and 347 .Ar filestamp 348 is the NTP seconds when the file was generated, in decimal digits. 349 This both guarantees uniqueness and simplifies maintenance 350 procedures, since all files can be quickly removed 351 by a 352 .Ic rm Pa ntpkey\&* 353 command or all files generated 354 at a specific time can be removed by a 355 .Ic rm Pa \&* Ns Ar filestamp 356 command. 357 To further reduce the risk of misconfiguration, 358 the first two lines of a file contain the file name 359 and generation date and time as comments. 360 .Ss Trusted Hosts and Groups 361 Each cryptographic configuration involves selection of a signature scheme 362 and identification scheme, called a cryptotype, 363 as explained in the 364 .Sx Authentication Options 365 section of 366 .Xr ntp.conf 5 . 367 The default cryptotype uses 368 .Cm RSA 369 encryption, 370 .Cm MD5 371 message digest 372 and 373 .Cm TC 374 identification. 375 First, configure a NTP subnet including one or more low\-stratum 376 trusted hosts from which all other hosts derive synchronization 377 directly or indirectly. 378 Trusted hosts have trusted certificates; 379 all other hosts have nontrusted certificates. 380 These hosts will automatically and dynamically build authoritative 381 certificate trails to one or more trusted hosts. 382 A trusted group is the set of all hosts that have, directly or indirectly, 383 a certificate trail ending at a trusted host. 384 The trail is defined by static configuration file entries 385 or dynamic means described on the 386 .Sx Automatic NTP Configuration Options 387 section of 388 .Xr ntp.conf 5 . 389 .Pp 390 On each trusted host as root, change to the keys directory. 391 To insure a fresh fileset, remove all 392 .Pa ntpkey 393 files. 394 Then run 395 .Nm 396 .Fl T 397 to generate keys and a trusted certificate. 398 On all other hosts do the same, but leave off the 399 .Fl T 400 flag to generate keys and nontrusted certificates. 401 When complete, start the NTP daemons beginning at the lowest stratum 402 and working up the tree. 403 It may take some time for Autokey to instantiate the certificate trails 404 throughout the subnet, but setting up the environment is completely automatic. 405 .Pp 406 If it is necessary to use a different sign key or different digest/signature 407 scheme than the default, run 408 .Nm 409 with the 410 .Fl S Ar type 411 option, where 412 .Ar type 413 is either 414 .Cm RSA 415 or 416 .Cm DSA . 417 The most frequent need to do this is when a 418 .Cm DSA Ns \-signed 419 certificate is used. 420 If it is necessary to use a different certificate scheme than the default, 421 run 422 .Nm 423 with the 424 .Fl c Ar scheme 425 option and selected 426 .Ar scheme 427 as needed. 428 If 429 .Nm 430 is run again without these options, it generates a new certificate 431 using the same scheme and sign key, and soft link. 432 .Pp 433 After setting up the environment it is advisable to update certificates 434 from time to time, if only to extend the validity interval. 435 Simply run 436 .Nm 437 with the same flags as before to generate new certificates 438 using existing keys, and soft links. 439 However, if the host or sign key is changed, 440 .Xr ntpd 1ntpdmdoc 441 should be restarted. 442 When 443 .Xr ntpd 1ntpdmdoc 444 is restarted, it loads any new files and restarts the protocol. 445 Other dependent hosts will continue as usual until signatures are refreshed, 446 at which time the protocol is restarted. 447 .Ss Identity Schemes 448 As mentioned on the Autonomous Authentication page, 449 the default 450 .Cm TC 451 identity scheme is vulnerable to a middleman attack. 452 However, there are more secure identity schemes available, 453 including 454 .Cm PC , IFF , GQ 455 and 456 .Cm MV 457 schemes described below. 458 These schemes are based on a TA, one or more trusted hosts 459 and some number of nontrusted hosts. 460 Trusted hosts prove identity using values provided by the TA, 461 while the remaining hosts prove identity using values provided 462 by a trusted host and certificate trails that end on that host. 463 The name of a trusted host is also the name of its sugroup 464 and also the subject and issuer name on its trusted certificate. 465 The TA is not necessarily a trusted host in this sense, but often is. 466 .Pp 467 In some schemes there are separate keys for servers and clients. 468 A server can also be a client of another server, 469 but a client can never be a server for another client. 470 In general, trusted hosts and nontrusted hosts that operate 471 as both server and client have parameter files that contain 472 both server and client keys. 473 Hosts that operate 474 only as clients have key files that contain only client keys. 475 .Pp 476 The PC scheme supports only one trusted host in the group. 477 On trusted host alice run 478 .Nm 479 .Fl P 480 .Fl p Ar password 481 to generate the host key file 482 .Pa ntpkey Ns _ Cm RSA Pa key_alice. Ar filestamp 483 and trusted private certificate file 484 .Pa ntpkey Ns _ Cm RSA\-MD5 _ Pa cert_alice. Ar filestamp , 485 and soft links. 486 Copy both files to all group hosts; 487 they replace the files which would be generated in other schemes. 488 On each host 489 .Ar bob 490 install a soft link from the generic name 491 .Pa ntpkey_host_ Ns Ar bob 492 to the host key file and soft link 493 .Pa ntpkey_cert_ Ns Ar bob 494 to the private certificate file. 495 Note the generic links are on bob, but point to files generated 496 by trusted host alice. 497 In this scheme it is not possible to refresh 498 either the keys or certificates without copying them 499 to all other hosts in the group, and recreating the soft links. 500 .Pp 501 For the 502 .Cm IFF 503 scheme proceed as in the 504 .Cm TC 505 scheme to generate keys 506 and certificates for all group hosts, then for every trusted host in the group, 507 generate the 508 .Cm IFF 509 parameter file. 510 On trusted host alice run 511 .Nm 512 .Fl T 513 .Fl I 514 .Fl p Ar password 515 to produce her parameter file 516 .Pa ntpkey_IFFpar_alice. Ns Ar filestamp , 517 which includes both server and client keys. 518 Copy this file to all group hosts that operate as both servers 519 and clients and install a soft link from the generic 520 .Pa ntpkey_iff_alice 521 to this file. 522 If there are no hosts restricted to operate only as clients, 523 there is nothing further to do. 524 As the 525 .Cm IFF 526 scheme is independent 527 of keys and certificates, these files can be refreshed as needed. 528 .Pp 529 If a rogue client has the parameter file, it could masquerade 530 as a legitimate server and present a middleman threat. 531 To eliminate this threat, the client keys can be extracted 532 from the parameter file and distributed to all restricted clients. 533 After generating the parameter file, on alice run 534 .Nm 535 .Fl e 536 and pipe the output to a file or email program. 537 Copy or email this file to all restricted clients. 538 On these clients install a soft link from the generic 539 .Pa ntpkey_iff_alice 540 to this file. 541 To further protect the integrity of the keys, 542 each file can be encrypted with a secret password. 543 .Pp 544 For the 545 .Cm GQ 546 scheme proceed as in the 547 .Cm TC 548 scheme to generate keys 549 and certificates for all group hosts, then for every trusted host 550 in the group, generate the 551 .Cm IFF 552 parameter file. 553 On trusted host alice run 554 .Nm 555 .Fl T 556 .Fl G 557 .Fl p Ar password 558 to produce her parameter file 559 .Pa ntpkey_GQpar_alice. Ns Ar filestamp , 560 which includes both server and client keys. 561 Copy this file to all group hosts and install a soft link 562 from the generic 563 .Pa ntpkey_gq_alice 564 to this file. 565 In addition, on each host 566 .Ar bob 567 install a soft link 568 from generic 569 .Pa ntpkey_gq_ Ns Ar bob 570 to this file. 571 As the 572 .Cm GQ 573 scheme updates the 574 .Cm GQ 575 parameters file and certificate 576 at the same time, keys and certificates can be regenerated as needed. 577 .Pp 578 For the 579 .Cm MV 580 scheme, proceed as in the 581 .Cm TC 582 scheme to generate keys 583 and certificates for all group hosts. 584 For illustration assume trish is the TA, alice one of several trusted hosts 585 and bob one of her clients. 586 On TA trish run 587 .Nm 588 .Fl V Ar n 589 .Fl p Ar password , 590 where 591 .Ar n 592 is the number of revokable keys (typically 5) to produce 593 the parameter file 594 .Pa ntpkeys_MVpar_trish. Ns Ar filestamp 595 and client key files 596 .Pa ntpkeys_MVkey Ns Ar d _ Pa trish. Ar filestamp 597 where 598 .Ar d 599 is the key number (0 \&< 600 .Ar d 601 \&< 602 .Ar n ) . 603 Copy the parameter file to alice and install a soft link 604 from the generic 605 .Pa ntpkey_mv_alice 606 to this file. 607 Copy one of the client key files to alice for later distribution 608 to her clients. 609 It does not matter which client key file goes to alice, 610 since they all work the same way. 611 Alice copies the client key file to all of her clients. 612 On client bob install a soft link from generic 613 .Pa ntpkey_mvkey_bob 614 to the client key file. 615 As the 616 .Cm MV 617 scheme is independent of keys and certificates, 618 these files can be refreshed as needed. 619 .Ss Command Line Options 620 .Bl -tag -width indent 621 .It Fl b Fl \-imbits Ns = Ar modulus 622 Set the number of bits in the identity modulus for generating identity keys to 623 .Ar modulus 624 bits. 625 The number of bits in the identity modulus defaults to 256, but can be set to 626 values from 256 to 2048 (32 to 256 octets). 627 Use the larger moduli with caution, as this can consume considerable computing 628 resources and increases the size of authenticated packets. 629 .It Fl c Fl \-certificate Ns = Ar scheme 630 Select certificate signature encryption/message digest scheme. 631 The 632 .Ar scheme 633 can be one of the following: 634 .Cm RSA\-MD2 , RSA\-MD5 , RSA\-MDC2 , RSA\-SHA , RSA\-SHA1 , RSA\-RIPEMD160 , DSA\-SHA , 635 or 636 .Cm DSA\-SHA1 . 637 Note that 638 .Cm RSA 639 schemes must be used with an 640 .Cm RSA 641 sign key and 642 .Cm DSA 643 schemes must be used with a 644 .Cm DSA 645 sign key. 646 The default without this option is 647 .Cm RSA\-MD5 . 648 If compatibility with FIPS 140\-2 is required, either the 649 .Cm DSA\-SHA 650 or 651 .Cm DSA\-SHA1 652 scheme must be used. 653 .It Fl C Fl \-cipher Ns = Ar cipher 654 Select the OpenSSL cipher to encrypt the files containing private keys. 655 The default without this option is three\-key triple DES in CBC mode, 656 .Cm des\-ede3\-cbc . 657 The 658 .Ic openssl Fl h 659 command provided with OpenSSL displays available ciphers. 660 .It Fl d Fl \-debug\-level 661 Increase debugging verbosity level. 662 This option displays the cryptographic data produced in eye\-friendly billboards. 663 .It Fl D Fl \-set\-debug\-level Ns = Ar level 664 Set the debugging verbosity to 665 .Ar level . 666 This option displays the cryptographic data produced in eye\-friendly billboards. 667 .It Fl e Fl \-id\-key 668 Write the 669 .Cm IFF 670 or 671 .Cm GQ 672 public parameters from the 673 .Ar IFFkey or GQkey 674 client keys file previously specified 675 as unencrypted data to the standard output stream 676 .Pa stdout . 677 This is intended for automatic key distribution by email. 678 .It Fl G Fl \-gq\-params 679 Generate a new encrypted 680 .Cm GQ 681 parameters and key file for the Guillou\-Quisquater (GQ) identity scheme. 682 This option is mutually exclusive with the 683 .Fl I 684 and 685 .Fl V 686 options. 687 .It Fl H Fl \-host\-key 688 Generate a new encrypted 689 .Cm RSA 690 public/private host key file. 691 .It Fl I Fl \-iffkey 692 Generate a new encrypted 693 .Cm IFF 694 key file for the Schnorr (IFF) identity scheme. 695 This option is mutually exclusive with the 696 .Fl G 697 and 698 Fl V 699 options. 700 .It Fl i Fl \-ident Ns = Ar group 701 Set the optional Autokey group name to 702 .Ar group . 703 This is used in the identity scheme parameter file names of 704 .Cm IFF , GQ , 705 and 706 .Cm MV 707 client parameters files. 708 In that role, the default is the host name if no group is provided. 709 The group name, if specified using 710 .Fl i 711 or 712 .Fl s 713 following an 714 .Ql @ 715 character, is also used in certificate subject and issuer names in the form 716 .Ar host @ group 717 and should match the group specified via 718 .Ic crypto Cm ident 719 or 720 .Ic server Cm ident 721 in the ntpd configuration file. 722 .It Fl l Fl \-lifetime Ns = Ar days 723 Set the lifetime for certificate expiration to 724 .Ar days . 725 The default lifetime is one year (365 days). 726 .It Fl m Fl \-modulus Ns = Ar bits 727 Set the number of bits in the prime modulus for generating files to 728 .Ar bits . 729 The modulus defaults to 512, but can be set from 256 to 2048 (32 to 256 octets). 730 Use the larger moduli with caution, as this can consume considerable computing 731 resources and increases the size of authenticated packets. 732 .It Fl M Fl \-md5key 733 Generate a new symmetric keys file containing 10 734 .Cm MD5 735 keys, and if OpenSSL is available, 10 736 .Cm SHA 737 keys. 738 An 739 .Cm MD5 740 key is a string of 20 random printable ASCII characters, while a 741 .Cm SHA 742 key is a string of 40 random hex digits. 743 The file can be edited using a text editor to change the key type or key content. 744 This option is mutually exclusive with all other options. 745 .It Fl p Fl \-password Ns = Ar passwd 746 Set the password for reading and writing encrypted files to 747 .Ar passwd . 748 These include the host, sign and identify key files. 749 By default, the password is the string returned by the Unix 750 .Ic hostname 751 command. 752 .It Fl P Fl \-pvt\-cert 753 Generate a new private certificate used by the 754 .Cm PC 755 identity scheme. 756 By default, the program generates public certificates. 757 Note: the PC identity scheme is not recommended for new installations. 758 .It Fl q Fl \-export\-passwd Ns = Ar passwd 759 Set the password for writing encrypted 760 .Cm IFF , GQ and MV 761 identity files redirected to 762 .Pa stdout 763 to 764 .Ar passwd . 765 In effect, these files are decrypted with the 766 .Fl p 767 password, then encrypted with the 768 .Fl q 769 password. 770 By default, the password is the string returned by the Unix 771 .Ic hostname 772 command. 773 .It Fl s Fl \-subject\-key Ns = Ar Oo host Oc Op @ Ar group 774 Specify the Autokey host name, where 775 .Ar host 776 is the optional host name and 777 .Ar group 778 is the optional group name. 779 The host name, and if provided, group name are used in 780 .Ar host @ group 781 form as certificate subject and issuer. 782 Specifying 783 .Fl s @ Ar group 784 is allowed, and results in leaving the host name unchanged, as with 785 .Fl i Ar group . 786 The group name, or if no group is provided, the host name are also used in the 787 file names of 788 .Cm IFF , GQ , 789 and 790 .Cm MV 791 identity scheme client parameter files. 792 If 793 .Ar host 794 is not specified, the default host name is the string returned by the Unix 795 .Ic hostname 796 command. 797 .It Fl S Fl \-sign\-key Ns = Op Cm RSA | DSA 798 Generate a new encrypted public/private sign key file of the specified type. 799 By default, the sign key is the host key and has the same type. 800 If compatibility with FIPS 140\-2 is required, the sign key type must be 801 .Cm DSA . 802 .It Fl T Fl \-trusted\-cert 803 Generate a trusted certificate. 804 By default, the program generates a non\-trusted certificate. 805 .It Fl V Fl \-mv\-params Ar nkeys 806 Generate 807 .Ar nkeys 808 encrypted server keys and parameters for the Mu\-Varadharajan (MV) 809 identity scheme. 810 This option is mutually exclusive with the 811 .Fl I 812 and 813 .Fl G 814 options. 815 Note: support for this option should be considered a work in progress. 816 .El 817 .Ss Random Seed File 818 All cryptographically sound key generation schemes must have means 819 to randomize the entropy seed used to initialize 820 the internal pseudo\-random number generator used 821 by the library routines. 822 The OpenSSL library uses a designated random seed file for this purpose. 823 The file must be available when starting the NTP daemon and 824 .Nm 825 program. 826 If a site supports OpenSSL or its companion OpenSSH, 827 it is very likely that means to do this are already available. 828 .Pp 829 It is important to understand that entropy must be evolved 830 for each generation, for otherwise the random number sequence 831 would be predictable. 832 Various means dependent on external events, such as keystroke intervals, 833 can be used to do this and some systems have built\-in entropy sources. 834 Suitable means are described in the OpenSSL software documentation, 835 but are outside the scope of this page. 836 .Pp 837 The entropy seed used by the OpenSSL library is contained in a file, 838 usually called 839 .Pa .rnd , 840 which must be available when starting the NTP daemon 841 or the 842 .Nm 843 program. 844 The NTP daemon will first look for the file 845 using the path specified by the 846 .Cm randfile 847 subcommand of the 848 .Ic crypto 849 configuration command. 850 If not specified in this way, or when starting the 851 .Nm 852 program, 853 the OpenSSL library will look for the file using the path specified 854 by the 855 .Ev RANDFILE 856 environment variable in the user home directory, 857 whether root or some other user. 858 If the 859 .Ev RANDFILE 860 environment variable is not present, 861 the library will look for the 862 .Pa .rnd 863 file in the user home directory. 864 Since both the 865 .Nm 866 program and 867 .Xr ntpd 1ntpdmdoc 868 daemon must run as root, the logical place to put this file is in 869 .Pa /.rnd 870 or 871 .Pa /root/.rnd . 872 If the file is not available or cannot be written, 873 the daemon exits with a message to the system log and the program 874 exits with a suitable error message. 875 .Ss Cryptographic Data Files 876 All file formats begin with two nonencrypted lines. 877 The first line contains the file name, including the generated host name 878 and filestamp, in the format 879 .Pa ntpkey_ Ns Ar key _ Ar name . Ar filestamp , 880 where 881 .Ar key 882 is the key or parameter type, 883 .Ar name 884 is the host or group name and 885 .Ar filestamp 886 is the filestamp (NTP seconds) when the file was created. 887 By convention, 888 .Ar key 889 names in generated file names include both upper and lower case 890 characters, while 891 .Ar key 892 names in generated link names include only lower case characters. 893 The filestamp is not used in generated link names. 894 The second line contains the datestamp in conventional Unix 895 .Pa date 896 format. 897 Lines beginning with 898 .Ql # 899 are considered comments and ignored by the 900 .Nm 901 program and 902 .Xr ntpd 1ntpdmdoc 903 daemon. 904 .Pp 905 The remainder of the file contains cryptographic data, encoded first using ASN.1 906 rules, then encrypted if necessary, and finally written in PEM\-encoded 907 printable ASCII text, preceded and followed by MIME content identifier lines. 908 .Pp 909 The format of the symmetric keys file, ordinarily named 910 .Pa ntp.keys , 911 is somewhat different than the other files in the interest of backward compatibility. 912 Ordinarily, the file is generated by this program, but it can be constructed 913 and edited using an ordinary text editor. 914 .Bd -literal -unfilled -offset center 915 # ntpkey_MD5key_bk.ntp.org.3595864945 916 # Thu Dec 12 19:22:25 2013 917 1 MD5 L";Nw<\`.I<f4U0)247"i # MD5 key 918 2 MD5 &>l0%XXK9O'51VwV<xq~ # MD5 key 919 3 MD5 lb4zLW~d^!K:]RsD'qb6 # MD5 key 920 4 MD5 Yue:tL[+vR)M\`n~bY,'? # MD5 key 921 5 MD5 B;fx'Kgr/&4ZTbL6=RxA # MD5 key 922 6 MD5 4eYwa\`o}3i@@V@..R9!l # MD5 key 923 7 MD5 \`A.([h+;wTQ|xfi%Sn_! # MD5 key 924 8 MD5 45:V,r4]l6y^JH6"Sh?F # MD5 key 925 9 MD5 3\-5vcn*6l29DS?Xdsg)* # MD5 key 926 10 MD5 2late4Me # MD5 key 927 11 SHA1 a27872d3030a9025b8446c751b4551a7629af65c # SHA1 key 928 12 SHA1 21bc3b4865dbb9e920902abdccb3e04ff97a5e74 # SHA1 key 929 13 SHA1 2b7736fe24fef5ba85ae11594132ab5d6f6daba9 # SHA1 key 930 14 SHA a5332809c8878dd3a5b918819108a111509aeceb # SHA key 931 15 MD2 2fe16c88c760ff2f16d4267e36c1aa6c926e6964 # MD2 key 932 16 MD4 b2691811dc19cfc0e2f9bcacd74213f29812183d # MD4 key 933 17 MD5 e4d6735b8bdad58ec5ffcb087300a17f7fef1f7c # MD5 key 934 18 MDC2 a8d5e2315c025bf3a79174c87fbd10477de2eabc # MDC2 key 935 19 RIPEMD160 77ca332cafb30e3cafb174dcd5b80ded7ba9b3d2 # RIPEMD160 key 936 20 AES128CMAC f92ff73eee86c1e7dc638d6489a04e4e555af878 # AES128CMAC key 937 .Ed 938 .D1 Figure 1. Typical Symmetric Key File 939 .Pp 940 Figure 1 shows a typical symmetric keys file used by the reference 941 implementation. 942 Following the header the keys are entered one per line in the format 943 .D1 Ar keyno Ar type Ar key 944 where 945 .Ar keyno 946 is a positive integer in the range 1\-65535; 947 .Ar type 948 is the key type for the message digest algorithm, which in the absence of the 949 OpenSSL library must be 950 .Cm MD5 951 to designate the MD5 message digest algorithm; 952 if the OpenSSL library is installed, the key type can be any 953 message digest algorithm supported by that library; 954 however, if compatibility with FIPS 140\-2 is required, 955 the key type must be either 956 .Cm SHA 957 or 958 .Cm SHA1 ; 959 .Ar key 960 is the key itself, 961 which is a printable ASCII string 20 characters or less in length: 962 each character is chosen from the 93 printable characters 963 in the range 0x21 through 0x7e ( 964 .Ql ! 965 through 966 .Ql ~ 967 \&) excluding space and the 968 .Ql # 969 character, and terminated by whitespace or a 970 .Ql # 971 character. 972 An OpenSSL key consists of a hex\-encoded ASCII string of 40 characters, which 973 is truncated as necessary. 974 .Pp 975 Note that the keys used by the 976 .Xr ntpq 1ntpqmdoc 977 and 978 .Xr ntpdc 1ntpdcmdoc 979 programs 980 are checked against passwords requested by the programs 981 and entered by hand, so it is generally appropriate to specify these keys 982 in human readable ASCII format. 983 .Pp 984 The 985 .Nm 986 program generates a symmetric keys file 987 .Pa ntpkey_MD5key_ Ns Ar hostname Ns . Ns Ar filestamp . 988 Since the file contains private shared keys, 989 it should be visible only to root and distributed by secure means 990 to other subnet hosts. 991 The NTP daemon loads the file 992 .Pa ntp.keys , 993 so 994 .Nm 995 installs a soft link from this name to the generated file. 996 Subsequently, similar soft links must be installed by manual 997 or automated means on the other subnet hosts. 998 While this file is not used with the Autokey Version 2 protocol, 999 it is needed to authenticate some remote configuration commands 1000 used by the 1001 .Xr ntpq 1ntpqmdoc 1002 and 1003 .Xr ntpdc 1ntpdcmdoc 1004 utilities. 1005 .Sh "OPTIONS" 1006 .Bl -tag 1007 .It Fl b Ar imbits , Fl \-imbits Ns = Ns Ar imbits 1008 identity modulus bits. 1009 This option takes an integer number as its argument. 1010 The value of 1011 .Ar imbits 1012 is constrained to being: 1013 .in +4 1014 .nf 1015 .na 1016 in the range 256 through 2048 1017 .fi 1018 .in -4 1019 .sp 1020 The number of bits in the identity modulus. The default is 256. 1021 .It Fl c Ar scheme , Fl \-certificate Ns = Ns Ar scheme 1022 certificate scheme. 1023 .sp 1024 scheme is one of 1025 RSA\-MD2, RSA\-MD5, RSA\-MDC2, RSA\-SHA, RSA\-SHA1, RSA\-RIPEMD160, 1026 DSA\-SHA, or DSA\-SHA1. 1027 .sp 1028 Select the certificate signature encryption/message digest scheme. 1029 Note that RSA schemes must be used with a RSA sign key and DSA 1030 schemes must be used with a DSA sign key. The default without 1031 this option is RSA\-MD5. 1032 .It Fl C Ar cipher , Fl \-cipher Ns = Ns Ar cipher 1033 privatekey cipher. 1034 .sp 1035 Select the cipher which is used to encrypt the files containing 1036 private keys. The default is three\-key triple DES in CBC mode, 1037 equivalent to "\fB\-C des\-ede3\-cbc\fP". The openssl tool lists ciphers 1038 available in "\fBopenssl \-h\fP" output. 1039 .It Fl d , Fl \-debug\-level 1040 Increase debug verbosity level. 1041 This option may appear an unlimited number of times. 1042 .sp 1043 .It Fl D Ar number , Fl \-set\-debug\-level Ns = Ns Ar number 1044 Set the debug verbosity level. 1045 This option may appear an unlimited number of times. 1046 This option takes an integer number as its argument. 1047 .sp 1048 .It Fl e , Fl \-id\-key 1049 Write IFF or GQ identity keys. 1050 .sp 1051 Write the public parameters from the IFF or GQ client keys to 1052 the standard output. 1053 This is intended for automatic key distribution by email. 1054 .It Fl G , Fl \-gq\-params 1055 Generate GQ parameters and keys. 1056 .sp 1057 Generate parameters and keys for the GQ identification scheme, 1058 obsoleting any that may exist. 1059 .It Fl H , Fl \-host\-key 1060 generate RSA host key. 1061 .sp 1062 Generate new host keys, obsoleting any that may exist. 1063 .It Fl I , Fl \-iffkey 1064 generate IFF parameters. 1065 .sp 1066 Generate parameters for the IFF identification scheme, obsoleting 1067 any that may exist. 1068 .It Fl i Ar group , Fl \-ident Ns = Ns Ar group 1069 set Autokey group name. 1070 .sp 1071 Set the optional Autokey group name to name. This is used in 1072 the file name of IFF, GQ, and MV client parameters files. In 1073 that role, the default is the host name if this option is not 1074 provided. The group name, if specified using \fB\-i/\-\-ident\fP or 1075 using \fB\-s/\-\-subject\-name\fP following an '\fB@\fP' character, 1076 is also a part of the self\-signed host certificate subject and 1077 issuer names in the form \fBhost@group\fP and should match the 1078 \'\fBcrypto ident\fP' or '\fBserver ident\fP' configuration in the 1079 \fBntpd\fP configuration file. 1080 .It Fl l Ar lifetime , Fl \-lifetime Ns = Ns Ar lifetime 1081 set certificate lifetime. 1082 This option takes an integer number as its argument. 1083 .sp 1084 Set the certificate expiration to lifetime days from now. 1085 .It Fl m Ar modulus , Fl \-modulus Ns = Ns Ar modulus 1086 prime modulus. 1087 This option takes an integer number as its argument. 1088 The value of 1089 .Ar modulus 1090 is constrained to being: 1091 .in +4 1092 .nf 1093 .na 1094 in the range 256 through 2048 1095 .fi 1096 .in -4 1097 .sp 1098 The number of bits in the prime modulus. The default is 512. 1099 .It Fl M , Fl \-md5key 1100 generate symmetric keys. 1101 .sp 1102 Generate symmetric keys, obsoleting any that may exist. 1103 .It Fl P , Fl \-pvt\-cert 1104 generate PC private certificate. 1105 .sp 1106 Generate a private certificate. By default, the program generates 1107 public certificates. 1108 .It Fl p Ar passwd , Fl \-password Ns = Ns Ar passwd 1109 local private password. 1110 .sp 1111 Local files containing private data are encrypted with the 1112 DES\-CBC algorithm and the specified password. The same password 1113 must be specified to the local ntpd via the "crypto pw password" 1114 configuration command. The default password is the local 1115 hostname. 1116 .It Fl q Ar passwd , Fl \-export\-passwd Ns = Ns Ar passwd 1117 export IFF or GQ group keys with password. 1118 .sp 1119 Export IFF or GQ identity group keys to the standard output, 1120 encrypted with the DES\-CBC algorithm and the specified password. 1121 The same password must be specified to the remote ntpd via the 1122 "crypto pw password" configuration command. See also the option 1123 -\-id\-key (\-e) for unencrypted exports. 1124 .It Fl s Ar host@group , Fl \-subject\-name Ns = Ns Ar host@group 1125 set host and optionally group name. 1126 .sp 1127 Set the Autokey host name, and optionally, group name specified 1128 following an '\fB@\fP' character. The host name is used in the file 1129 name of generated host and signing certificates, without the 1130 group name. The host name, and if provided, group name are used 1131 in \fBhost@group\fP form for the host certificate subject and issuer 1132 fields. Specifying '\fB\-s @group\fP' is allowed, and results in 1133 leaving the host name unchanged while appending \fB@group\fP to the 1134 subject and issuer fields, as with \fB\-i group\fP. The group name, or 1135 if not provided, the host name are also used in the file names 1136 of IFF, GQ, and MV client parameter files. 1137 .It Fl S Ar sign , Fl \-sign\-key Ns = Ns Ar sign 1138 generate sign key (RSA or DSA). 1139 .sp 1140 Generate a new sign key of the designated type, obsoleting any 1141 that may exist. By default, the program uses the host key as the 1142 sign key. 1143 .It Fl T , Fl \-trusted\-cert 1144 trusted certificate (TC scheme). 1145 .sp 1146 Generate a trusted certificate. By default, the program generates 1147 a non\-trusted certificate. 1148 .It Fl V Ar num , Fl \-mv\-params Ns = Ns Ar num 1149 generate <num> MV parameters. 1150 This option takes an integer number as its argument. 1151 .sp 1152 Generate parameters and keys for the Mu\-Varadharajan (MV) 1153 identification scheme. 1154 .It Fl v Ar num , Fl \-mv\-keys Ns = Ns Ar num 1155 update <num> MV keys. 1156 This option takes an integer number as its argument. 1157 .sp 1158 This option has not been fully documented. 1159 .It Fl \&? , Fl \-help 1160 Display usage information and exit. 1161 .It Fl \&! , Fl \-more\-help 1162 Pass the extended usage information through a pager. 1163 .It Fl > Oo Ar cfgfile Oc , Fl \-save\-opts Oo Ns = Ns Ar cfgfile Oc 1164 Save the option state to \fIcfgfile\fP. The default is the \fIlast\fP 1165 configuration file listed in the \fBOPTION PRESETS\fP section, below. 1166 The command will exit after updating the config file. 1167 .It Fl < Ar cfgfile , Fl \-load\-opts Ns = Ns Ar cfgfile , Fl \-no\-load\-opts 1168 Load options from \fIcfgfile\fP. 1169 The \fIno\-load\-opts\fP form will disable the loading 1170 of earlier config/rc/ini files. \fI\-\-no\-load\-opts\fP is handled early, 1171 out of order. 1172 .It Fl \-version Op Brq Ar v|c|n 1173 Output version of program and exit. The default mode is `v', a simple 1174 version. The `c' mode will print copyright information and `n' will 1175 print the full copyright notice. 1176 .El 1177 .Sh "OPTION PRESETS" 1178 Any option that is not marked as \fInot presettable\fP may be preset 1179 by loading values from configuration ("RC" or ".INI") file(s) and values from 1180 environment variables named: 1181 .nf 1182 \fBNTP_KEYGEN_<option\-name>\fP or \fBNTP_KEYGEN\fP 1183 .fi 1184 .ad 1185 The environmental presets take precedence (are processed later than) 1186 the configuration files. 1187 The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP". 1188 If any of these are directories, then the file \fI.ntprc\fP 1189 is searched for within those directories. 1190 .Sh USAGE 1191 .Sh "ENVIRONMENT" 1192 See \fBOPTION PRESETS\fP for configuration environment variables. 1193 .Sh "FILES" 1194 See \fBOPTION PRESETS\fP for configuration files. 1195 .Sh "EXIT STATUS" 1196 One of the following exit values will be returned: 1197 .Bl -tag 1198 .It 0 " (EXIT_SUCCESS)" 1199 Successful program execution. 1200 .It 1 " (EXIT_FAILURE)" 1201 The operation failed or the command syntax was not valid. 1202 .It 66 " (EX_NOINPUT)" 1203 A specified configuration file could not be loaded. 1204 .It 70 " (EX_SOFTWARE)" 1205 libopts had an internal operational error. Please report 1206 it to autogen\-users@lists.sourceforge.net. Thank you. 1207 .El 1208 .Sh "AUTHORS" 1209 The University of Delaware and Network Time Foundation 1210 .Sh "COPYRIGHT" 1211 Copyright (C) 1992\-2020 The University of Delaware and Network Time Foundation all rights reserved. 1212 This program is released under the terms of the NTP license, <http://ntp.org/license>. 1213 .Sh BUGS 1214 It can take quite a while to generate some cryptographic values. 1215 .Pp 1216 Please report bugs to http://bugs.ntp.org . 1217 .Pp 1218 Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org 1219 .Sh NOTES 1220 Portions of this document came from FreeBSD. 1221 .Pp 1222 This manual page was \fIAutoGen\fP\-erated from the \fBntp\-keygen\fP 1223 option definitions.