ntp-keygen.mdoc.in revision 362716
1.Dd June 23 2020 2.Dt NTP_KEYGEN @NTP_KEYGEN_MS@ 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 19All arguments must be options. 20.Pp 21.Sh DESCRIPTION 22This program generates cryptographic data files used by the NTPv4 23authentication and identification schemes. 24It can generate message digest keys used in symmetric key cryptography and, 25if the OpenSSL software library has been installed, it can generate host keys, 26signing keys, certificates, and identity keys and parameters used in Autokey 27public key cryptography. 28These files are used for cookie encryption, 29digital signature, and challenge/response identification algorithms 30compatible with the Internet standard security infrastructure. 31.Pp 32The message digest symmetric keys file is generated in a format 33compatible with NTPv3. 34All other files are in PEM\-encoded printable ASCII format, 35so they can be embedded as MIME attachments in email to other sites 36and certificate authorities. 37By default, files are not encrypted. 38.Pp 39When used to generate message digest symmetric keys, the program 40produces a file containing ten pseudo\-random printable ASCII strings 41suitable for the MD5 message digest algorithm included in the 42distribution. 43If the OpenSSL library is installed, it produces an additional ten 44hex\-encoded random bit strings suitable for SHA1, AES\-128\-CMAC, and 45other message digest algorithms. 46The message digest symmetric keys file must be distributed and stored 47using secure means beyond the scope of NTP itself. 48Besides the keys used for ordinary NTP associations, additional keys 49can be defined as passwords for the 50.Xr ntpq @NTPQ_MS@ 51and 52.Xr ntpdc @NTPDC_MS@ 53utility programs. 54.Pp 55The remaining generated files are compatible with other OpenSSL 56applications and other Public Key Infrastructure (PKI) resources. 57Certificates generated by this program are compatible with extant 58industry practice, although some users might find the interpretation of 59X509v3 extension fields somewhat liberal. 60However, the identity keys are probably not compatible with anything 61other than Autokey. 62.Pp 63Some files used by this program are encrypted using a private password. 64The 65.Fl p 66option specifies the read password for local encrypted files and the 67.Fl q 68option the write password for encrypted files sent to remote sites. 69If no password is specified, the host name returned by the Unix 70.Xr hostname 1 71command, normally the DNS name of the host, is used as the the default read 72password, for convenience. 73The 74.Nm 75program prompts for the password if it reads an encrypted file 76and the password is missing or incorrect. 77If an encrypted file is read successfully and 78no write password is specified, the read password is used 79as the write password by default. 80.Pp 81The 82.Cm pw 83option of the 84.Ic crypto 85.Xr ntpd @NTPD_MS@ 86configuration command specifies the read 87password for previously encrypted local files. 88This must match the local read password used by this program. 89If not specified, the host name is used. 90Thus, if files are generated by this program without an explicit password, 91they can be read back by 92.Xr ntpd @NTPD_MS@ 93without specifying an explicit password but only on the same host. 94If the write password used for encryption is specified as the host name, 95these files can be read by that host with no explicit password. 96.Pp 97Normally, encrypted files for each host are generated by that host and 98used only by that host, although exceptions exist as noted later on 99this page. 100The symmetric keys file, normally called 101.Pa ntp.keys , 102is usually installed in 103.Pa /etc . 104Other files and links are usually installed in 105.Pa /usr/local/etc , 106which is normally in a shared filesystem in 107NFS\-mounted networks and cannot be changed by shared clients. 108In these cases, NFS clients can specify the files in another 109directory such as 110.Pa /etc 111using the 112.Ic keysdir 113.Xr ntpd @NTPD_MS@ 114configuration file command. 115.Pp 116This program directs commentary and error messages to the standard 117error stream 118.Pa stderr 119and remote files to the standard output stream 120.Pa stdout 121where they can be piped to other applications or redirected to files. 122The names used for generated files and links all begin with the 123string 124.Pa ntpkey\&* 125and include the file type, generating host and filestamp, 126as described in the 127.Sx "Cryptographic Data Files" 128section below. 129.Ss Running the Program 130The safest way to run the 131.Nm 132program is logged in directly as root. 133The recommended procedure is change to the 134.Ar keys 135directory, usually 136.Pa /usr/local/etc , 137then run the program. 138.Pp 139To test and gain experience with Autokey concepts, log in as root and 140change to the 141.Ar keys 142directory, usually 143.Pa /usr/local/etc . 144When run for the first time, or if all files with names beginning with 145.Pa ntpkey\&* 146have been removed, use the 147.Nm 148command without arguments to generate a default 149.Cm RSA 150host key and matching 151.Cm RSA\-MD5 152certificate file with expiration date one year hence, 153which is all that is necessary in many cases. 154The program also generates soft links from the generic names 155to the respective files. 156If run again without options, the program uses the 157existing keys and parameters and generates a new certificate file with 158new expiration date one year hence, and soft link. 159.Pp 160The host key is used to encrypt the cookie when required and so must be 161.Cm RSA 162type. 163By default, the host key is also the sign key used to encrypt signatures. 164When necessary, a different sign key can be specified and this can be 165either 166.Cm RSA 167or 168.Cm DSA 169type. 170By default, the message digest type is 171.Cm MD5 , 172but any combination 173of sign key type and message digest type supported by the OpenSSL library 174can be specified, including those using the 175.Cm AES128CMAC , MD2 , MD5 , MDC2 , SHA , SHA1 176and 177.Cm RIPE160 178message digest algorithms. 179However, the scheme specified in the certificate must be compatible 180with the sign key. 181Certificates using any digest algorithm are compatible with 182.Cm RSA 183sign keys; 184however, only 185.Cm SHA 186and 187.Cm SHA1 188certificates are compatible with 189.Cm DSA 190sign keys. 191.Pp 192Private/public key files and certificates are compatible with 193other OpenSSL applications and very likely other libraries as well. 194Certificates or certificate requests derived from them should be compatible 195with extant industry practice, although some users might find 196the interpretation of X509v3 extension fields somewhat liberal. 197However, the identification parameter files, although encoded 198as the other files, are probably not compatible with anything other than Autokey. 199.Pp 200Running the program as other than root and using the Unix 201.Xr su 1 202command 203to assume root may not work properly, since by default the OpenSSL library 204looks for the random seed file 205.Pa .rnd 206in the user home directory. 207However, there should be only one 208.Pa .rnd , 209most conveniently 210in the root directory, so it is convenient to define the 211.Ev RANDFILE 212environment variable used by the OpenSSL library as the path to 213.Pa .rnd . 214.Pp 215Installing the keys as root might not work in NFS\-mounted 216shared file systems, as NFS clients may not be able to write 217to the shared keys directory, even as root. 218In this case, NFS clients can specify the files in another 219directory such as 220.Pa /etc 221using the 222.Ic keysdir 223.Xr ntpd @NTPD_MS@ 224configuration file command. 225There is no need for one client to read the keys and certificates 226of other clients or servers, as these data are obtained automatically 227by the Autokey protocol. 228.Pp 229Ordinarily, cryptographic files are generated by the host that uses them, 230but it is possible for a trusted agent (TA) to generate these files 231for other hosts; however, in such cases files should always be encrypted. 232The subject name and trusted name default to the hostname 233of the host generating the files, but can be changed by command line options. 234It is convenient to designate the owner name and trusted name 235as the subject and issuer fields, respectively, of the certificate. 236The owner name is also used for the host and sign key files, 237while the trusted name is used for the identity files. 238.Pp 239All files are installed by default in the keys directory 240.Pa /usr/local/etc , 241which is normally in a shared filesystem 242in NFS\-mounted networks. 243The actual location of the keys directory 244and each file can be overridden by configuration commands, 245but this is not recommended. 246Normally, the files for each host are generated by that host 247and used only by that host, although exceptions exist 248as noted later on this page. 249.Pp 250Normally, files containing private values, 251including the host key, sign key and identification parameters, 252are permitted root read/write\-only; 253while others containing public values are permitted world readable. 254Alternatively, files containing private values can be encrypted 255and these files permitted world readable, 256which simplifies maintenance in shared file systems. 257Since uniqueness is insured by the 258.Ar hostname 259and 260.Ar filestamp 261file name extensions, the files for an NTP server and 262dependent clients can all be installed in the same shared directory. 263.Pp 264The recommended practice is to keep the file name extensions 265when installing a file and to install a soft link 266from the generic names specified elsewhere on this page 267to the generated files. 268This allows new file generations to be activated simply 269by changing the link. 270If a link is present, 271.Xr ntpd @NTPD_MS@ 272follows it to the file name to extract the 273.Ar filestamp . 274If a link is not present, 275.Xr ntpd @NTPD_MS@ 276extracts the 277.Ar filestamp 278from the file itself. 279This allows clients to verify that the file and generation times 280are always current. 281The 282.Nm 283program uses the same 284.Ar filestamp 285extension for all files generated 286at one time, so each generation is distinct and can be readily 287recognized in monitoring data. 288.Pp 289Run the command on as many hosts as necessary. 290Designate one of them as the trusted host (TH) using 291.Nm 292with the 293.Fl T 294option and configure it to synchronize from reliable Internet servers. 295Then configure the other hosts to synchronize to the TH directly or 296indirectly. 297A certificate trail is created when Autokey asks the immediately 298ascendant host towards the TH to sign its certificate, which is then 299provided to the immediately descendant host on request. 300All group hosts should have acyclic certificate trails ending on the TH. 301.Pp 302The host key is used to encrypt the cookie when required and so must be 303RSA type. 304By default, the host key is also the sign key used to encrypt 305signatures. 306A different sign key can be assigned using the 307.Fl S 308option and this can be either 309.Cm RSA 310or 311.Cm DSA 312type. 313By default, the signature 314message digest type is 315.Cm MD5 , 316but any combination of sign key type and 317message digest type supported by the OpenSSL library can be specified 318using the 319.Fl c 320option. 321.Pp 322The rules say cryptographic media should be generated with proventic 323filestamps, which means the host should already be synchronized before 324this program is run. 325This of course creates a chicken\-and\-egg problem 326when the host is started for the first time. 327Accordingly, the host time 328should be set by some other means, such as eyeball\-and\-wristwatch, at 329least so that the certificate lifetime is within the current year. 330After that and when the host is synchronized to a proventic source, the 331certificate should be re\-generated. 332.Pp 333Additional information on trusted groups and identity schemes is on the 334.Dq Autokey Public\-Key Authentication 335page. 336.Pp 337File names begin with the prefix 338.Pa ntpkey Ns _ 339and end with the suffix 340.Pa _ Ns Ar hostname . Ar filestamp , 341where 342.Ar hostname 343is the owner name, usually the string returned 344by the Unix 345.Xr hostname 1 346command, and 347.Ar filestamp 348is the NTP seconds when the file was generated, in decimal digits. 349This both guarantees uniqueness and simplifies maintenance 350procedures, since all files can be quickly removed 351by a 352.Ic rm Pa ntpkey\&* 353command or all files generated 354at a specific time can be removed by a 355.Ic rm Pa \&* Ns Ar filestamp 356command. 357To further reduce the risk of misconfiguration, 358the first two lines of a file contain the file name 359and generation date and time as comments. 360.Ss Trusted Hosts and Groups 361Each cryptographic configuration involves selection of a signature scheme 362and identification scheme, called a cryptotype, 363as explained in the 364.Sx Authentication Options 365section of 366.Xr ntp.conf 5 . 367The default cryptotype uses 368.Cm RSA 369encryption, 370.Cm MD5 371message digest 372and 373.Cm TC 374identification. 375First, configure a NTP subnet including one or more low\-stratum 376trusted hosts from which all other hosts derive synchronization 377directly or indirectly. 378Trusted hosts have trusted certificates; 379all other hosts have nontrusted certificates. 380These hosts will automatically and dynamically build authoritative 381certificate trails to one or more trusted hosts. 382A trusted group is the set of all hosts that have, directly or indirectly, 383a certificate trail ending at a trusted host. 384The trail is defined by static configuration file entries 385or dynamic means described on the 386.Sx Automatic NTP Configuration Options 387section of 388.Xr ntp.conf 5 . 389.Pp 390On each trusted host as root, change to the keys directory. 391To insure a fresh fileset, remove all 392.Pa ntpkey 393files. 394Then run 395.Nm 396.Fl T 397to generate keys and a trusted certificate. 398On all other hosts do the same, but leave off the 399.Fl T 400flag to generate keys and nontrusted certificates. 401When complete, start the NTP daemons beginning at the lowest stratum 402and working up the tree. 403It may take some time for Autokey to instantiate the certificate trails 404throughout the subnet, but setting up the environment is completely automatic. 405.Pp 406If it is necessary to use a different sign key or different digest/signature 407scheme than the default, run 408.Nm 409with the 410.Fl S Ar type 411option, where 412.Ar type 413is either 414.Cm RSA 415or 416.Cm DSA . 417The most frequent need to do this is when a 418.Cm DSA Ns \-signed 419certificate is used. 420If it is necessary to use a different certificate scheme than the default, 421run 422.Nm 423with the 424.Fl c Ar scheme 425option and selected 426.Ar scheme 427as needed. 428If 429.Nm 430is run again without these options, it generates a new certificate 431using the same scheme and sign key, and soft link. 432.Pp 433After setting up the environment it is advisable to update certificates 434from time to time, if only to extend the validity interval. 435Simply run 436.Nm 437with the same flags as before to generate new certificates 438using existing keys, and soft links. 439However, if the host or sign key is changed, 440.Xr ntpd @NTPD_MS@ 441should be restarted. 442When 443.Xr ntpd @NTPD_MS@ 444is restarted, it loads any new files and restarts the protocol. 445Other dependent hosts will continue as usual until signatures are refreshed, 446at which time the protocol is restarted. 447.Ss Identity Schemes 448As mentioned on the Autonomous Authentication page, 449the default 450.Cm TC 451identity scheme is vulnerable to a middleman attack. 452However, there are more secure identity schemes available, 453including 454.Cm PC , IFF , GQ 455and 456.Cm MV 457schemes described below. 458These schemes are based on a TA, one or more trusted hosts 459and some number of nontrusted hosts. 460Trusted hosts prove identity using values provided by the TA, 461while the remaining hosts prove identity using values provided 462by a trusted host and certificate trails that end on that host. 463The name of a trusted host is also the name of its sugroup 464and also the subject and issuer name on its trusted certificate. 465The TA is not necessarily a trusted host in this sense, but often is. 466.Pp 467In some schemes there are separate keys for servers and clients. 468A server can also be a client of another server, 469but a client can never be a server for another client. 470In general, trusted hosts and nontrusted hosts that operate 471as both server and client have parameter files that contain 472both server and client keys. 473Hosts that operate 474only as clients have key files that contain only client keys. 475.Pp 476The PC scheme supports only one trusted host in the group. 477On trusted host alice run 478.Nm 479.Fl P 480.Fl p Ar password 481to generate the host key file 482.Pa ntpkey Ns _ Cm RSA Pa key_alice. Ar filestamp 483and trusted private certificate file 484.Pa ntpkey Ns _ Cm RSA\-MD5 _ Pa cert_alice. Ar filestamp , 485and soft links. 486Copy both files to all group hosts; 487they replace the files which would be generated in other schemes. 488On each host 489.Ar bob 490install a soft link from the generic name 491.Pa ntpkey_host_ Ns Ar bob 492to the host key file and soft link 493.Pa ntpkey_cert_ Ns Ar bob 494to the private certificate file. 495Note the generic links are on bob, but point to files generated 496by trusted host alice. 497In this scheme it is not possible to refresh 498either the keys or certificates without copying them 499to all other hosts in the group, and recreating the soft links. 500.Pp 501For the 502.Cm IFF 503scheme proceed as in the 504.Cm TC 505scheme to generate keys 506and certificates for all group hosts, then for every trusted host in the group, 507generate the 508.Cm IFF 509parameter file. 510On trusted host alice run 511.Nm 512.Fl T 513.Fl I 514.Fl p Ar password 515to produce her parameter file 516.Pa ntpkey_IFFpar_alice. Ns Ar filestamp , 517which includes both server and client keys. 518Copy this file to all group hosts that operate as both servers 519and clients and install a soft link from the generic 520.Pa ntpkey_iff_alice 521to this file. 522If there are no hosts restricted to operate only as clients, 523there is nothing further to do. 524As the 525.Cm IFF 526scheme is independent 527of keys and certificates, these files can be refreshed as needed. 528.Pp 529If a rogue client has the parameter file, it could masquerade 530as a legitimate server and present a middleman threat. 531To eliminate this threat, the client keys can be extracted 532from the parameter file and distributed to all restricted clients. 533After generating the parameter file, on alice run 534.Nm 535.Fl e 536and pipe the output to a file or email program. 537Copy or email this file to all restricted clients. 538On these clients install a soft link from the generic 539.Pa ntpkey_iff_alice 540to this file. 541To further protect the integrity of the keys, 542each file can be encrypted with a secret password. 543.Pp 544For the 545.Cm GQ 546scheme proceed as in the 547.Cm TC 548scheme to generate keys 549and certificates for all group hosts, then for every trusted host 550in the group, generate the 551.Cm IFF 552parameter file. 553On trusted host alice run 554.Nm 555.Fl T 556.Fl G 557.Fl p Ar password 558to produce her parameter file 559.Pa ntpkey_GQpar_alice. Ns Ar filestamp , 560which includes both server and client keys. 561Copy this file to all group hosts and install a soft link 562from the generic 563.Pa ntpkey_gq_alice 564to this file. 565In addition, on each host 566.Ar bob 567install a soft link 568from generic 569.Pa ntpkey_gq_ Ns Ar bob 570to this file. 571As the 572.Cm GQ 573scheme updates the 574.Cm GQ 575parameters file and certificate 576at the same time, keys and certificates can be regenerated as needed. 577.Pp 578For the 579.Cm MV 580scheme, proceed as in the 581.Cm TC 582scheme to generate keys 583and certificates for all group hosts. 584For illustration assume trish is the TA, alice one of several trusted hosts 585and bob one of her clients. 586On TA trish run 587.Nm 588.Fl V Ar n 589.Fl p Ar password , 590where 591.Ar n 592is the number of revokable keys (typically 5) to produce 593the parameter file 594.Pa ntpkeys_MVpar_trish. Ns Ar filestamp 595and client key files 596.Pa ntpkeys_MVkey Ns Ar d _ Pa trish. Ar filestamp 597where 598.Ar d 599is the key number (0 \&< 600.Ar d 601\&< 602.Ar n ) . 603Copy the parameter file to alice and install a soft link 604from the generic 605.Pa ntpkey_mv_alice 606to this file. 607Copy one of the client key files to alice for later distribution 608to her clients. 609It does not matter which client key file goes to alice, 610since they all work the same way. 611Alice copies the client key file to all of her clients. 612On client bob install a soft link from generic 613.Pa ntpkey_mvkey_bob 614to the client key file. 615As the 616.Cm MV 617scheme is independent of keys and certificates, 618these 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 622Set the number of bits in the identity modulus for generating identity keys to 623.Ar modulus 624bits. 625The number of bits in the identity modulus defaults to 256, but can be set to 626values from 256 to 2048 (32 to 256 octets). 627Use the larger moduli with caution, as this can consume considerable computing 628resources and increases the size of authenticated packets. 629.It Fl c Fl \-certificate Ns = Ar scheme 630Select certificate signature encryption/message digest scheme. 631The 632.Ar scheme 633can be one of the following: 634.Cm RSA\-MD2 , RSA\-MD5 , RSA\-MDC2 , RSA\-SHA , RSA\-SHA1 , RSA\-RIPEMD160 , DSA\-SHA , 635or 636.Cm DSA\-SHA1 . 637Note that 638.Cm RSA 639schemes must be used with an 640.Cm RSA 641sign key and 642.Cm DSA 643schemes must be used with a 644.Cm DSA 645sign key. 646The default without this option is 647.Cm RSA\-MD5 . 648If compatibility with FIPS 140\-2 is required, either the 649.Cm DSA\-SHA 650or 651.Cm DSA\-SHA1 652scheme must be used. 653.It Fl C Fl \-cipher Ns = Ar cipher 654Select the OpenSSL cipher to encrypt the files containing private keys. 655The default without this option is three\-key triple DES in CBC mode, 656.Cm des\-ede3\-cbc . 657The 658.Ic openssl Fl h 659command provided with OpenSSL displays available ciphers. 660.It Fl d Fl \-debug\-level 661Increase debugging verbosity level. 662This option displays the cryptographic data produced in eye\-friendly billboards. 663.It Fl D Fl \-set\-debug\-level Ns = Ar level 664Set the debugging verbosity to 665.Ar level . 666This option displays the cryptographic data produced in eye\-friendly billboards. 667.It Fl e Fl \-id\-key 668Write the 669.Cm IFF 670or 671.Cm GQ 672public parameters from the 673.Ar IFFkey or GQkey 674client keys file previously specified 675as unencrypted data to the standard output stream 676.Pa stdout . 677This is intended for automatic key distribution by email. 678.It Fl G Fl \-gq\-params 679Generate a new encrypted 680.Cm GQ 681parameters and key file for the Guillou\-Quisquater (GQ) identity scheme. 682This option is mutually exclusive with the 683.Fl I 684and 685.Fl V 686options. 687.It Fl H Fl \-host\-key 688Generate a new encrypted 689.Cm RSA 690public/private host key file. 691.It Fl I Fl \-iffkey 692Generate a new encrypted 693.Cm IFF 694key file for the Schnorr (IFF) identity scheme. 695This option is mutually exclusive with the 696.Fl G 697and 698Fl V 699options. 700.It Fl i Fl \-ident Ns = Ar group 701Set the optional Autokey group name to 702.Ar group . 703This is used in the identity scheme parameter file names of 704.Cm IFF , GQ , 705and 706.Cm MV 707client parameters files. 708In that role, the default is the host name if no group is provided. 709The group name, if specified using 710.Fl i 711or 712.Fl s 713following an 714.Ql @ 715character, is also used in certificate subject and issuer names in the form 716.Ar host @ group 717and should match the group specified via 718.Ic crypto Cm ident 719or 720.Ic server Cm ident 721in the ntpd configuration file. 722.It Fl l Fl \-lifetime Ns = Ar days 723Set the lifetime for certificate expiration to 724.Ar days . 725The default lifetime is one year (365 days). 726.It Fl m Fl \-modulus Ns = Ar bits 727Set the number of bits in the prime modulus for generating files to 728.Ar bits . 729The modulus defaults to 512, but can be set from 256 to 2048 (32 to 256 octets). 730Use the larger moduli with caution, as this can consume considerable computing 731resources and increases the size of authenticated packets. 732.It Fl M Fl \-md5key 733Generate a new symmetric keys file containing 10 734.Cm MD5 735keys, and if OpenSSL is available, 10 736.Cm SHA 737keys. 738An 739.Cm MD5 740key is a string of 20 random printable ASCII characters, while a 741.Cm SHA 742key is a string of 40 random hex digits. 743The file can be edited using a text editor to change the key type or key content. 744This option is mutually exclusive with all other options. 745.It Fl p Fl \-password Ns = Ar passwd 746Set the password for reading and writing encrypted files to 747.Ar passwd . 748These include the host, sign and identify key files. 749By default, the password is the string returned by the Unix 750.Ic hostname 751command. 752.It Fl P Fl \-pvt\-cert 753Generate a new private certificate used by the 754.Cm PC 755identity scheme. 756By default, the program generates public certificates. 757Note: the PC identity scheme is not recommended for new installations. 758.It Fl q Fl \-export\-passwd Ns = Ar passwd 759Set the password for writing encrypted 760.Cm IFF , GQ and MV 761identity files redirected to 762.Pa stdout 763to 764.Ar passwd . 765In effect, these files are decrypted with the 766.Fl p 767password, then encrypted with the 768.Fl q 769password. 770By default, the password is the string returned by the Unix 771.Ic hostname 772command. 773.It Fl s Fl \-subject\-key Ns = Ar Oo host Oc Op @ Ar group 774Specify the Autokey host name, where 775.Ar host 776is the optional host name and 777.Ar group 778is the optional group name. 779The host name, and if provided, group name are used in 780.Ar host @ group 781form as certificate subject and issuer. 782Specifying 783.Fl s @ Ar group 784is allowed, and results in leaving the host name unchanged, as with 785.Fl i Ar group . 786The group name, or if no group is provided, the host name are also used in the 787file names of 788.Cm IFF , GQ , 789and 790.Cm MV 791identity scheme client parameter files. 792If 793.Ar host 794is not specified, the default host name is the string returned by the Unix 795.Ic hostname 796command. 797.It Fl S Fl \-sign\-key Ns = Op Cm RSA | DSA 798Generate a new encrypted public/private sign key file of the specified type. 799By default, the sign key is the host key and has the same type. 800If compatibility with FIPS 140\-2 is required, the sign key type must be 801.Cm DSA . 802.It Fl T Fl \-trusted\-cert 803Generate a trusted certificate. 804By default, the program generates a non\-trusted certificate. 805.It Fl V Fl \-mv\-params Ar nkeys 806Generate 807.Ar nkeys 808encrypted server keys and parameters for the Mu\-Varadharajan (MV) 809identity scheme. 810This option is mutually exclusive with the 811.Fl I 812and 813.Fl G 814options. 815Note: support for this option should be considered a work in progress. 816.El 817.Ss Random Seed File 818All cryptographically sound key generation schemes must have means 819to randomize the entropy seed used to initialize 820the internal pseudo\-random number generator used 821by the library routines. 822The OpenSSL library uses a designated random seed file for this purpose. 823The file must be available when starting the NTP daemon and 824.Nm 825program. 826If a site supports OpenSSL or its companion OpenSSH, 827it is very likely that means to do this are already available. 828.Pp 829It is important to understand that entropy must be evolved 830for each generation, for otherwise the random number sequence 831would be predictable. 832Various means dependent on external events, such as keystroke intervals, 833can be used to do this and some systems have built\-in entropy sources. 834Suitable means are described in the OpenSSL software documentation, 835but are outside the scope of this page. 836.Pp 837The entropy seed used by the OpenSSL library is contained in a file, 838usually called 839.Pa .rnd , 840which must be available when starting the NTP daemon 841or the 842.Nm 843program. 844The NTP daemon will first look for the file 845using the path specified by the 846.Cm randfile 847subcommand of the 848.Ic crypto 849configuration command. 850If not specified in this way, or when starting the 851.Nm 852program, 853the OpenSSL library will look for the file using the path specified 854by the 855.Ev RANDFILE 856environment variable in the user home directory, 857whether root or some other user. 858If the 859.Ev RANDFILE 860environment variable is not present, 861the library will look for the 862.Pa .rnd 863file in the user home directory. 864Since both the 865.Nm 866program and 867.Xr ntpd @NTPD_MS@ 868daemon must run as root, the logical place to put this file is in 869.Pa /.rnd 870or 871.Pa /root/.rnd . 872If the file is not available or cannot be written, 873the daemon exits with a message to the system log and the program 874exits with a suitable error message. 875.Ss Cryptographic Data Files 876All file formats begin with two nonencrypted lines. 877The first line contains the file name, including the generated host name 878and filestamp, in the format 879.Pa ntpkey_ Ns Ar key _ Ar name . Ar filestamp , 880where 881.Ar key 882is the key or parameter type, 883.Ar name 884is the host or group name and 885.Ar filestamp 886is the filestamp (NTP seconds) when the file was created. 887By convention, 888.Ar key 889names in generated file names include both upper and lower case 890characters, while 891.Ar key 892names in generated link names include only lower case characters. 893The filestamp is not used in generated link names. 894The second line contains the datestamp in conventional Unix 895.Pa date 896format. 897Lines beginning with 898.Ql # 899are considered comments and ignored by the 900.Nm 901program and 902.Xr ntpd @NTPD_MS@ 903daemon. 904.Pp 905The remainder of the file contains cryptographic data, encoded first using ASN.1 906rules, then encrypted if necessary, and finally written in PEM\-encoded 907printable ASCII text, preceded and followed by MIME content identifier lines. 908.Pp 909The format of the symmetric keys file, ordinarily named 910.Pa ntp.keys , 911is somewhat different than the other files in the interest of backward compatibility. 912Ordinarily, the file is generated by this program, but it can be constructed 913and 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 9171 MD5 L";Nw<\`.I<f4U0)247"i # MD5 key 9182 MD5 &>l0%XXK9O'51VwV<xq~ # MD5 key 9193 MD5 lb4zLW~d^!K:]RsD'qb6 # MD5 key 9204 MD5 Yue:tL[+vR)M\`n~bY,'? # MD5 key 9215 MD5 B;fx'Kgr/&4ZTbL6=RxA # MD5 key 9226 MD5 4eYwa\`o}3i@@V@..R9!l # MD5 key 9237 MD5 \`A.([h+;wTQ|xfi%Sn_! # MD5 key 9248 MD5 45:V,r4]l6y^JH6"Sh?F # MD5 key 9259 MD5 3\-5vcn*6l29DS?Xdsg)* # MD5 key 92610 MD5 2late4Me # MD5 key 92711 SHA1 a27872d3030a9025b8446c751b4551a7629af65c # SHA1 key 92812 SHA1 21bc3b4865dbb9e920902abdccb3e04ff97a5e74 # SHA1 key 92913 SHA1 2b7736fe24fef5ba85ae11594132ab5d6f6daba9 # SHA1 key 93014 SHA a5332809c8878dd3a5b918819108a111509aeceb # SHA key 93115 MD2 2fe16c88c760ff2f16d4267e36c1aa6c926e6964 # MD2 key 93216 MD4 b2691811dc19cfc0e2f9bcacd74213f29812183d # MD4 key 93317 MD5 e4d6735b8bdad58ec5ffcb087300a17f7fef1f7c # MD5 key 93418 MDC2 a8d5e2315c025bf3a79174c87fbd10477de2eabc # MDC2 key 93519 RIPEMD160 77ca332cafb30e3cafb174dcd5b80ded7ba9b3d2 # RIPEMD160 key 93620 AES128CMAC f92ff73eee86c1e7dc638d6489a04e4e555af878 # AES128CMAC key 937.Ed 938.D1 Figure 1. Typical Symmetric Key File 939.Pp 940Figure 1 shows a typical symmetric keys file used by the reference 941implementation. 942Following the header the keys are entered one per line in the format 943.D1 Ar keyno Ar type Ar key 944where 945.Ar keyno 946is a positive integer in the range 1\-65535; 947.Ar type 948is the key type for the message digest algorithm, which in the absence of the 949OpenSSL library must be 950.Cm MD5 951to designate the MD5 message digest algorithm; 952if the OpenSSL library is installed, the key type can be any 953message digest algorithm supported by that library; 954however, if compatibility with FIPS 140\-2 is required, 955the key type must be either 956.Cm SHA 957or 958.Cm SHA1 ; 959.Ar key 960is the key itself, 961which is a printable ASCII string 20 characters or less in length: 962each character is chosen from the 93 printable characters 963in the range 0x21 through 0x7e ( 964.Ql ! 965through 966.Ql ~ 967\&) excluding space and the 968.Ql # 969character, and terminated by whitespace or a 970.Ql # 971character. 972An OpenSSL key consists of a hex\-encoded ASCII string of 40 characters, which 973is truncated as necessary. 974.Pp 975Note that the keys used by the 976.Xr ntpq @NTPQ_MS@ 977and 978.Xr ntpdc @NTPDC_MS@ 979programs 980are checked against passwords requested by the programs 981and entered by hand, so it is generally appropriate to specify these keys 982in human readable ASCII format. 983.Pp 984The 985.Nm 986program generates a symmetric keys file 987.Pa ntpkey_MD5key_ Ns Ar hostname Ns . Ns Ar filestamp . 988Since the file contains private shared keys, 989it should be visible only to root and distributed by secure means 990to other subnet hosts. 991The NTP daemon loads the file 992.Pa ntp.keys , 993so 994.Nm 995installs a soft link from this name to the generated file. 996Subsequently, similar soft links must be installed by manual 997or automated means on the other subnet hosts. 998While this file is not used with the Autokey Version 2 protocol, 999it is needed to authenticate some remote configuration commands 1000used by the 1001.Xr ntpq @NTPQ_MS@ 1002and 1003.Xr ntpdc @NTPDC_MS@ 1004utilities. 1005.Sh "OPTIONS" 1006.Bl -tag 1007.It Fl b Ar imbits , Fl \-imbits Ns = Ns Ar imbits 1008identity modulus bits. 1009This option takes an integer number as its argument. 1010The value of 1011.Ar imbits 1012is constrained to being: 1013.in +4 1014.nf 1015.na 1016in the range 256 through 2048 1017.fi 1018.in -4 1019.sp 1020The number of bits in the identity modulus. The default is 256. 1021.It Fl c Ar scheme , Fl \-certificate Ns = Ns Ar scheme 1022certificate scheme. 1023.sp 1024scheme is one of 1025RSA\-MD2, RSA\-MD5, RSA\-MDC2, RSA\-SHA, RSA\-SHA1, RSA\-RIPEMD160, 1026DSA\-SHA, or DSA\-SHA1. 1027.sp 1028Select the certificate signature encryption/message digest scheme. 1029Note that RSA schemes must be used with a RSA sign key and DSA 1030schemes must be used with a DSA sign key. The default without 1031this option is RSA\-MD5. 1032.It Fl C Ar cipher , Fl \-cipher Ns = Ns Ar cipher 1033privatekey cipher. 1034.sp 1035Select the cipher which is used to encrypt the files containing 1036private keys. The default is three\-key triple DES in CBC mode, 1037equivalent to "\fB\-C des\-ede3\-cbc\fP". The openssl tool lists ciphers 1038available in "\fBopenssl \-h\fP" output. 1039.It Fl d , Fl \-debug\-level 1040Increase debug verbosity level. 1041This option may appear an unlimited number of times. 1042.sp 1043.It Fl D Ar number , Fl \-set\-debug\-level Ns = Ns Ar number 1044Set the debug verbosity level. 1045This option may appear an unlimited number of times. 1046This option takes an integer number as its argument. 1047.sp 1048.It Fl e , Fl \-id\-key 1049Write IFF or GQ identity keys. 1050.sp 1051Write the public parameters from the IFF or GQ client keys to 1052the standard output. 1053This is intended for automatic key distribution by email. 1054.It Fl G , Fl \-gq\-params 1055Generate GQ parameters and keys. 1056.sp 1057Generate parameters and keys for the GQ identification scheme, 1058obsoleting any that may exist. 1059.It Fl H , Fl \-host\-key 1060generate RSA host key. 1061.sp 1062Generate new host keys, obsoleting any that may exist. 1063.It Fl I , Fl \-iffkey 1064generate IFF parameters. 1065.sp 1066Generate parameters for the IFF identification scheme, obsoleting 1067any that may exist. 1068.It Fl i Ar group , Fl \-ident Ns = Ns Ar group 1069set Autokey group name. 1070.sp 1071Set the optional Autokey group name to name. This is used in 1072the file name of IFF, GQ, and MV client parameters files. In 1073that role, the default is the host name if this option is not 1074provided. The group name, if specified using \fB\-i/\-\-ident\fP or 1075using \fB\-s/\-\-subject\-name\fP following an '\fB@\fP' character, 1076is also a part of the self\-signed host certificate subject and 1077issuer 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 1081set certificate lifetime. 1082This option takes an integer number as its argument. 1083.sp 1084Set the certificate expiration to lifetime days from now. 1085.It Fl m Ar modulus , Fl \-modulus Ns = Ns Ar modulus 1086prime modulus. 1087This option takes an integer number as its argument. 1088The value of 1089.Ar modulus 1090is constrained to being: 1091.in +4 1092.nf 1093.na 1094in the range 256 through 2048 1095.fi 1096.in -4 1097.sp 1098The number of bits in the prime modulus. The default is 512. 1099.It Fl M , Fl \-md5key 1100generate symmetric keys. 1101.sp 1102Generate symmetric keys, obsoleting any that may exist. 1103.It Fl P , Fl \-pvt\-cert 1104generate PC private certificate. 1105.sp 1106Generate a private certificate. By default, the program generates 1107public certificates. 1108.It Fl p Ar passwd , Fl \-password Ns = Ns Ar passwd 1109local private password. 1110.sp 1111Local files containing private data are encrypted with the 1112DES\-CBC algorithm and the specified password. The same password 1113must be specified to the local ntpd via the "crypto pw password" 1114configuration command. The default password is the local 1115hostname. 1116.It Fl q Ar passwd , Fl \-export\-passwd Ns = Ns Ar passwd 1117export IFF or GQ group keys with password. 1118.sp 1119Export IFF or GQ identity group keys to the standard output, 1120encrypted with the DES\-CBC algorithm and the specified password. 1121The 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 1125set host and optionally group name. 1126.sp 1127Set the Autokey host name, and optionally, group name specified 1128following an '\fB@\fP' character. The host name is used in the file 1129name of generated host and signing certificates, without the 1130group name. The host name, and if provided, group name are used 1131in \fBhost@group\fP form for the host certificate subject and issuer 1132fields. Specifying '\fB\-s @group\fP' is allowed, and results in 1133leaving the host name unchanged while appending \fB@group\fP to the 1134subject and issuer fields, as with \fB\-i group\fP. The group name, or 1135if not provided, the host name are also used in the file names 1136of IFF, GQ, and MV client parameter files. 1137.It Fl S Ar sign , Fl \-sign\-key Ns = Ns Ar sign 1138generate sign key (RSA or DSA). 1139.sp 1140Generate a new sign key of the designated type, obsoleting any 1141that may exist. By default, the program uses the host key as the 1142sign key. 1143.It Fl T , Fl \-trusted\-cert 1144trusted certificate (TC scheme). 1145.sp 1146Generate a trusted certificate. By default, the program generates 1147a non\-trusted certificate. 1148.It Fl V Ar num , Fl \-mv\-params Ns = Ns Ar num 1149generate <num> MV parameters. 1150This option takes an integer number as its argument. 1151.sp 1152Generate parameters and keys for the Mu\-Varadharajan (MV) 1153identification scheme. 1154.It Fl v Ar num , Fl \-mv\-keys Ns = Ns Ar num 1155update <num> MV keys. 1156This option takes an integer number as its argument. 1157.sp 1158This option has not been fully documented. 1159.It Fl \&? , Fl \-help 1160Display usage information and exit. 1161.It Fl \&! , Fl \-more\-help 1162Pass the extended usage information through a pager. 1163.It Fl > Oo Ar cfgfile Oc , Fl \-save\-opts Oo Ns = Ns Ar cfgfile Oc 1164Save the option state to \fIcfgfile\fP. The default is the \fIlast\fP 1165configuration file listed in the \fBOPTION PRESETS\fP section, below. 1166The command will exit after updating the config file. 1167.It Fl < Ar cfgfile , Fl \-load\-opts Ns = Ns Ar cfgfile , Fl \-no\-load\-opts 1168Load options from \fIcfgfile\fP. 1169The \fIno\-load\-opts\fP form will disable the loading 1170of earlier config/rc/ini files. \fI\-\-no\-load\-opts\fP is handled early, 1171out of order. 1172.It Fl \-version Op Brq Ar v|c|n 1173Output version of program and exit. The default mode is `v', a simple 1174version. The `c' mode will print copyright information and `n' will 1175print the full copyright notice. 1176.El 1177.Sh "OPTION PRESETS" 1178Any option that is not marked as \fInot presettable\fP may be preset 1179by loading values from configuration ("RC" or ".INI") file(s) and values from 1180environment variables named: 1181.nf 1182 \fBNTP_KEYGEN_<option\-name>\fP or \fBNTP_KEYGEN\fP 1183.fi 1184.ad 1185The environmental presets take precedence (are processed later than) 1186the configuration files. 1187The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP". 1188If any of these are directories, then the file \fI.ntprc\fP 1189is searched for within those directories. 1190.Sh USAGE 1191.Sh "ENVIRONMENT" 1192See \fBOPTION PRESETS\fP for configuration environment variables. 1193.Sh "FILES" 1194See \fBOPTION PRESETS\fP for configuration files. 1195.Sh "EXIT STATUS" 1196One of the following exit values will be returned: 1197.Bl -tag 1198.It 0 " (EXIT_SUCCESS)" 1199Successful program execution. 1200.It 1 " (EXIT_FAILURE)" 1201The operation failed or the command syntax was not valid. 1202.It 66 " (EX_NOINPUT)" 1203A specified configuration file could not be loaded. 1204.It 70 " (EX_SOFTWARE)" 1205libopts had an internal operational error. Please report 1206it to autogen\-users@lists.sourceforge.net. Thank you. 1207.El 1208.Sh "AUTHORS" 1209The University of Delaware and Network Time Foundation 1210.Sh "COPYRIGHT" 1211Copyright (C) 1992\-2020 The University of Delaware and Network Time Foundation all rights reserved. 1212This program is released under the terms of the NTP license, <http://ntp.org/license>. 1213.Sh BUGS 1214It can take quite a while to generate some cryptographic values. 1215.Pp 1216Please report bugs to http://bugs.ntp.org . 1217.Pp 1218Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org 1219.Sh NOTES 1220Portions of this document came from FreeBSD. 1221.Pp 1222This manual page was \fIAutoGen\fP\-erated from the \fBntp\-keygen\fP 1223option definitions. 1224