ntp-keygen.1ntp-keygenmdoc revision 309007
1.Dd November 21 2016 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 November 21, 2016 at 08:03:48 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 generates MD5 key files used in symmetric key cryptography. 25In addition, if the OpenSSL software library has been installed, 26it generates keys, certificate and identity files used in public key 27cryptography. 28These files are used for cookie encryption, 29digital signature and challenge/response identification algorithms 30compatible with the Internet standard security infrastructure. 31.Pp 32All files are in PEM\-encoded printable ASCII format, 33so they can be embedded as MIME attachments in mail to other sites 34and certificate authorities. 35By default, files are not encrypted. 36.Pp 37When used to generate message digest keys, the program produces a file 38containing ten pseudo\-random printable ASCII strings suitable for the 39MD5 message digest algorithm included in the distribution. 40If the OpenSSL library is installed, it produces an additional ten 41hex\-encoded random bit strings suitable for the SHA1 and other message 42digest algorithms. 43The message digest keys file must be distributed and stored 44using secure means beyond the scope of NTP itself. 45Besides the keys used for ordinary NTP associations, additional keys 46can be defined as passwords for the 47.Xr ntpq 1ntpqmdoc 48and 49.Xr ntpdc 1ntpdcmdoc 50utility programs. 51.Pp 52The remaining generated files are compatible with other OpenSSL 53applications and other Public Key Infrastructure (PKI) resources. 54Certificates generated by this program are compatible with extant 55industry practice, although some users might find the interpretation of 56X509v3 extension fields somewhat liberal. 57However, the identity keys are probably not compatible with anything 58other than Autokey. 59.Pp 60Some files used by this program are encrypted using a private password. 61The 62.Fl p 63option specifies the password for local encrypted files and the 64.Fl q 65option the password for encrypted files sent to remote sites. 66If no password is specified, the host name returned by the Unix 67.Fn gethostname 68function, normally the DNS name of the host is used. 69.Pp 70The 71.Ar pw 72option of the 73.Ar crypto 74configuration command specifies the read 75password for previously encrypted local files. 76This must match the local password used by this program. 77If not specified, the host name is used. 78Thus, if files are generated by this program without password, 79they can be read back by 80.Ar ntpd 81without password but only on the same host. 82.Pp 83Normally, encrypted files for each host are generated by that host and 84used only by that host, although exceptions exist as noted later on 85this page. 86The symmetric keys file, normally called 87.Ar ntp.keys , 88is usually installed in 89.Pa /etc . 90Other files and links are usually installed in 91.Pa /usr/local/etc , 92which is normally in a shared filesystem in 93NFS\-mounted networks and cannot be changed by shared clients. 94The location of the keys directory can be changed by the 95.Ar keysdir 96configuration command in such cases. 97Normally, this is in 98.Pa /etc . 99.Pp 100This program directs commentary and error messages to the standard 101error stream 102.Ar stderr 103and remote files to the standard output stream 104.Ar stdout 105where they can be piped to other applications or redirected to files. 106The names used for generated files and links all begin with the 107string 108.Ar ntpkey 109and include the file type, generating host and filestamp, 110as described in the 111.Dq Cryptographic Data Files 112section below. 113.Ss Running the Program 114To test and gain experience with Autokey concepts, log in as root and 115change to the keys directory, usually 116.Pa /usr/local/etc 117When run for the first time, or if all files with names beginning with 118.Ar ntpkey 119have been removed, use the 120.Nm 121command without arguments to generate a 122default RSA host key and matching RSA\-MD5 certificate with expiration 123date one year hence. 124If run again without options, the program uses the 125existing keys and parameters and generates only a new certificate with 126new expiration date one year hence. 127.Pp 128Run the command on as many hosts as necessary. 129Designate one of them as the trusted host (TH) using 130.Nm 131with the 132.Fl T 133option and configure it to synchronize from reliable Internet servers. 134Then configure the other hosts to synchronize to the TH directly or 135indirectly. 136A certificate trail is created when Autokey asks the immediately 137ascendant host towards the TH to sign its certificate, which is then 138provided to the immediately descendant host on request. 139All group hosts should have acyclic certificate trails ending on the TH. 140.Pp 141The host key is used to encrypt the cookie when required and so must be 142RSA type. 143By default, the host key is also the sign key used to encrypt 144signatures. 145A different sign key can be assigned using the 146.Fl S 147option and this can be either RSA or DSA type. 148By default, the signature 149message digest type is MD5, but any combination of sign key type and 150message digest type supported by the OpenSSL library can be specified 151using the 152.Fl c 153option. 154The rules say cryptographic media should be generated with proventic 155filestamps, which means the host should already be synchronized before 156this program is run. 157This of course creates a chicken\-and\-egg problem 158when the host is started for the first time. 159Accordingly, the host time 160should be set by some other means, such as eyeball\-and\-wristwatch, at 161least so that the certificate lifetime is within the current year. 162After that and when the host is synchronized to a proventic source, the 163certificate should be re\-generated. 164.Pp 165Additional information on trusted groups and identity schemes is on the 166.Dq Autokey Public\-Key Authentication 167page. 168.Pp 169The 170.Xr ntpd 1ntpdmdoc 171configuration command 172.Ic crypto pw Ar password 173specifies the read password for previously encrypted files. 174The daemon expires on the spot if the password is missing 175or incorrect. 176For convenience, if a file has been previously encrypted, 177the default read password is the name of the host running 178the program. 179If the previous write password is specified as the host name, 180these files can be read by that host with no explicit password. 181.Pp 182File names begin with the prefix 183.Cm ntpkey_ 184and end with the postfix 185.Ar _hostname.filestamp , 186where 187.Ar hostname 188is the owner name, usually the string returned 189by the Unix gethostname() routine, and 190.Ar filestamp 191is the NTP seconds when the file was generated, in decimal digits. 192This both guarantees uniqueness and simplifies maintenance 193procedures, since all files can be quickly removed 194by a 195.Ic rm ntpkey\&* 196command or all files generated 197at a specific time can be removed by a 198.Ic rm 199.Ar \&*filestamp 200command. 201To further reduce the risk of misconfiguration, 202the first two lines of a file contain the file name 203and generation date and time as comments. 204.Pp 205All files are installed by default in the keys directory 206.Pa /usr/local/etc , 207which is normally in a shared filesystem 208in NFS\-mounted networks. 209The actual location of the keys directory 210and each file can be overridden by configuration commands, 211but this is not recommended. 212Normally, the files for each host are generated by that host 213and used only by that host, although exceptions exist 214as noted later on this page. 215.Pp 216Normally, files containing private values, 217including the host key, sign key and identification parameters, 218are permitted root read/write\-only; 219while others containing public values are permitted world readable. 220Alternatively, files containing private values can be encrypted 221and these files permitted world readable, 222which simplifies maintenance in shared file systems. 223Since uniqueness is insured by the hostname and 224file name extensions, the files for a NFS server and 225dependent clients can all be installed in the same shared directory. 226.Pp 227The recommended practice is to keep the file name extensions 228when installing a file and to install a soft link 229from the generic names specified elsewhere on this page 230to the generated files. 231This allows new file generations to be activated simply 232by changing the link. 233If a link is present, ntpd follows it to the file name 234to extract the filestamp. 235If a link is not present, 236.Xr ntpd 1ntpdmdoc 237extracts the filestamp from the file itself. 238This allows clients to verify that the file and generation times 239are always current. 240The 241.Nm 242program uses the same timestamp extension for all files generated 243at one time, so each generation is distinct and can be readily 244recognized in monitoring data. 245.Ss Running the program 246The safest way to run the 247.Nm 248program is logged in directly as root. 249The recommended procedure is change to the keys directory, 250usually 251.Pa /usr/local/etc , 252then run the program. 253When run for the first time, 254or if all 255.Cm ntpkey 256files have been removed, 257the program generates a RSA host key file and matching RSA\-MD5 certificate file, 258which is all that is necessary in many cases. 259The program also generates soft links from the generic names 260to the respective files. 261If run again, the program uses the same host key file, 262but generates a new certificate file and link. 263.Pp 264The host key is used to encrypt the cookie when required and so must be RSA type. 265By default, the host key is also the sign key used to encrypt signatures. 266When necessary, a different sign key can be specified and this can be 267either RSA or DSA type. 268By default, the message digest type is MD5, but any combination 269of sign key type and message digest type supported by the OpenSSL library 270can be specified, including those using the MD2, MD5, SHA, SHA1, MDC2 271and RIPE160 message digest algorithms. 272However, the scheme specified in the certificate must be compatible 273with the sign key. 274Certificates using any digest algorithm are compatible with RSA sign keys; 275however, only SHA and SHA1 certificates are compatible with DSA sign keys. 276.Pp 277Private/public key files and certificates are compatible with 278other OpenSSL applications and very likely other libraries as well. 279Certificates or certificate requests derived from them should be compatible 280with extant industry practice, although some users might find 281the interpretation of X509v3 extension fields somewhat liberal. 282However, the identification parameter files, although encoded 283as the other files, are probably not compatible with anything other than Autokey. 284.Pp 285Running the program as other than root and using the Unix 286.Ic su 287command 288to assume root may not work properly, since by default the OpenSSL library 289looks for the random seed file 290.Cm .rnd 291in the user home directory. 292However, there should be only one 293.Cm .rnd , 294most conveniently 295in the root directory, so it is convenient to define the 296.Cm $RANDFILE 297environment variable used by the OpenSSL library as the path to 298.Cm /.rnd . 299.Pp 300Installing the keys as root might not work in NFS\-mounted 301shared file systems, as NFS clients may not be able to write 302to the shared keys directory, even as root. 303In this case, NFS clients can specify the files in another 304directory such as 305.Pa /etc 306using the 307.Ic keysdir 308command. 309There is no need for one client to read the keys and certificates 310of other clients or servers, as these data are obtained automatically 311by the Autokey protocol. 312.Pp 313Ordinarily, cryptographic files are generated by the host that uses them, 314but it is possible for a trusted agent (TA) to generate these files 315for other hosts; however, in such cases files should always be encrypted. 316The subject name and trusted name default to the hostname 317of the host generating the files, but can be changed by command line options. 318It is convenient to designate the owner name and trusted name 319as the subject and issuer fields, respectively, of the certificate. 320The owner name is also used for the host and sign key files, 321while the trusted name is used for the identity files. 322.Pp 323All files are installed by default in the keys directory 324.Pa /usr/local/etc , 325which is normally in a shared filesystem 326in NFS\-mounted networks. 327The actual location of the keys directory 328and each file can be overridden by configuration commands, 329but this is not recommended. 330Normally, the files for each host are generated by that host 331and used only by that host, although exceptions exist 332as noted later on this page. 333.Pp 334Normally, files containing private values, 335including the host key, sign key and identification parameters, 336are permitted root read/write\-only; 337while others containing public values are permitted world readable. 338Alternatively, files containing private values can be encrypted 339and these files permitted world readable, 340which simplifies maintenance in shared file systems. 341Since uniqueness is insured by the hostname and 342file name extensions, the files for a NFS server and 343dependent clients can all be installed in the same shared directory. 344.Pp 345The recommended practice is to keep the file name extensions 346when installing a file and to install a soft link 347from the generic names specified elsewhere on this page 348to the generated files. 349This allows new file generations to be activated simply 350by changing the link. 351If a link is present, ntpd follows it to the file name 352to extract the filestamp. 353If a link is not present, 354.Xr ntpd 1ntpdmdoc 355extracts the filestamp from the file itself. 356This allows clients to verify that the file and generation times 357are always current. 358The 359.Nm 360program uses the same timestamp extension for all files generated 361at one time, so each generation is distinct and can be readily 362recognized in monitoring data. 363.Ss Running the program 364The safest way to run the 365.Nm 366program is logged in directly as root. 367The recommended procedure is change to the keys directory, 368usually 369.Pa /usr/local/etc , 370then run the program. 371When run for the first time, 372or if all 373.Cm ntpkey 374files have been removed, 375the program generates a RSA host key file and matching RSA\-MD5 certificate file, 376which is all that is necessary in many cases. 377The program also generates soft links from the generic names 378to the respective files. 379If run again, the program uses the same host key file, 380but generates a new certificate file and link. 381.Pp 382The host key is used to encrypt the cookie when required and so must be RSA type. 383By default, the host key is also the sign key used to encrypt signatures. 384When necessary, a different sign key can be specified and this can be 385either RSA or DSA type. 386By default, the message digest type is MD5, but any combination 387of sign key type and message digest type supported by the OpenSSL library 388can be specified, including those using the MD2, MD5, SHA, SHA1, MDC2 389and RIPE160 message digest algorithms. 390However, the scheme specified in the certificate must be compatible 391with the sign key. 392Certificates using any digest algorithm are compatible with RSA sign keys; 393however, only SHA and SHA1 certificates are compatible with DSA sign keys. 394.Pp 395Private/public key files and certificates are compatible with 396other OpenSSL applications and very likely other libraries as well. 397Certificates or certificate requests derived from them should be compatible 398with extant industry practice, although some users might find 399the interpretation of X509v3 extension fields somewhat liberal. 400However, the identification parameter files, although encoded 401as the other files, are probably not compatible with anything other than Autokey. 402.Pp 403Running the program as other than root and using the Unix 404.Ic su 405command 406to assume root may not work properly, since by default the OpenSSL library 407looks for the random seed file 408.Cm .rnd 409in the user home directory. 410However, there should be only one 411.Cm .rnd , 412most conveniently 413in the root directory, so it is convenient to define the 414.Cm $RANDFILE 415environment variable used by the OpenSSL library as the path to 416.Cm /.rnd . 417.Pp 418Installing the keys as root might not work in NFS\-mounted 419shared file systems, as NFS clients may not be able to write 420to the shared keys directory, even as root. 421In this case, NFS clients can specify the files in another 422directory such as 423.Pa /etc 424using the 425.Ic keysdir 426command. 427There is no need for one client to read the keys and certificates 428of other clients or servers, as these data are obtained automatically 429by the Autokey protocol. 430.Pp 431Ordinarily, cryptographic files are generated by the host that uses them, 432but it is possible for a trusted agent (TA) to generate these files 433for other hosts; however, in such cases files should always be encrypted. 434The subject name and trusted name default to the hostname 435of the host generating the files, but can be changed by command line options. 436It is convenient to designate the owner name and trusted name 437as the subject and issuer fields, respectively, of the certificate. 438The owner name is also used for the host and sign key files, 439while the trusted name is used for the identity files. 440seconds. 441seconds. 442s Trusted Hosts and Groups 443Each cryptographic configuration involves selection of a signature scheme 444and identification scheme, called a cryptotype, 445as explained in the 446.Sx Authentication Options 447section of 448.Xr ntp.conf 5 . 449The default cryptotype uses RSA encryption, MD5 message digest 450and TC identification. 451First, configure a NTP subnet including one or more low\-stratum 452trusted hosts from which all other hosts derive synchronization 453directly or indirectly. 454Trusted hosts have trusted certificates; 455all other hosts have nontrusted certificates. 456These hosts will automatically and dynamically build authoritative 457certificate trails to one or more trusted hosts. 458A trusted group is the set of all hosts that have, directly or indirectly, 459a certificate trail ending at a trusted host. 460The trail is defined by static configuration file entries 461or dynamic means described on the 462.Sx Automatic NTP Configuration Options 463section of 464.Xr ntp.conf 5 . 465.Pp 466On each trusted host as root, change to the keys directory. 467To insure a fresh fileset, remove all 468.Cm ntpkey 469files. 470Then run 471.Nm 472.Fl T 473to generate keys and a trusted certificate. 474On all other hosts do the same, but leave off the 475.Fl T 476flag to generate keys and nontrusted certificates. 477When complete, start the NTP daemons beginning at the lowest stratum 478and working up the tree. 479It may take some time for Autokey to instantiate the certificate trails 480throughout the subnet, but setting up the environment is completely automatic. 481.Pp 482If it is necessary to use a different sign key or different digest/signature 483scheme than the default, run 484.Nm 485with the 486.Fl S Ar type 487option, where 488.Ar type 489is either 490.Cm RSA 491or 492.Cm DSA . 493The most often need to do this is when a DSA\-signed certificate is used. 494If it is necessary to use a different certificate scheme than the default, 495run 496.Nm 497with the 498.Fl c Ar scheme 499option and selected 500.Ar scheme 501as needed. 502f 503.Nm 504is run again without these options, it generates a new certificate 505using the same scheme and sign key. 506.Pp 507After setting up the environment it is advisable to update certificates 508from time to time, if only to extend the validity interval. 509Simply run 510.Nm 511with the same flags as before to generate new certificates 512using existing keys. 513However, if the host or sign key is changed, 514.Xr ntpd 1ntpdmdoc 515should be restarted. 516When 517.Xr ntpd 1ntpdmdoc 518is restarted, it loads any new files and restarts the protocol. 519Other dependent hosts will continue as usual until signatures are refreshed, 520at which time the protocol is restarted. 521.Ss Identity Schemes 522As mentioned on the Autonomous Authentication page, 523the default TC identity scheme is vulnerable to a middleman attack. 524However, there are more secure identity schemes available, 525including PC, IFF, GQ and MV described on the 526.Qq Identification Schemes 527page 528(maybe available at 529.Li http://www.eecis.udel.edu/%7emills/keygen.html ) . 530These schemes are based on a TA, one or more trusted hosts 531and some number of nontrusted hosts. 532Trusted hosts prove identity using values provided by the TA, 533while the remaining hosts prove identity using values provided 534by a trusted host and certificate trails that end on that host. 535The name of a trusted host is also the name of its sugroup 536and also the subject and issuer name on its trusted certificate. 537The TA is not necessarily a trusted host in this sense, but often is. 538.Pp 539In some schemes there are separate keys for servers and clients. 540A server can also be a client of another server, 541but a client can never be a server for another client. 542In general, trusted hosts and nontrusted hosts that operate 543as both server and client have parameter files that contain 544both server and client keys. 545Hosts that operate 546only as clients have key files that contain only client keys. 547.Pp 548The PC scheme supports only one trusted host in the group. 549On trusted host alice run 550.Nm 551.Fl P 552.Fl p Ar password 553to generate the host key file 554.Pa ntpkey_RSAkey_ Ns Ar alice.filestamp 555and trusted private certificate file 556.Pa ntpkey_RSA\-MD5_cert_ Ns Ar alice.filestamp . 557Copy both files to all group hosts; 558they replace the files which would be generated in other schemes. 559On each host bob install a soft link from the generic name 560.Pa ntpkey_host_ Ns Ar bob 561to the host key file and soft link 562.Pa ntpkey_cert_ Ns Ar bob 563to the private certificate file. 564Note the generic links are on bob, but point to files generated 565by trusted host alice. 566In this scheme it is not possible to refresh 567either the keys or certificates without copying them 568to all other hosts in the group. 569.Pp 570For the IFF scheme proceed as in the TC scheme to generate keys 571and certificates for all group hosts, then for every trusted host in the group, 572generate the IFF parameter file. 573On trusted host alice run 574.Nm 575.Fl T 576.Fl I 577.Fl p Ar password 578to produce her parameter file 579.Pa ntpkey_IFFpar_ Ns Ar alice.filestamp , 580which includes both server and client keys. 581Copy this file to all group hosts that operate as both servers 582and clients and install a soft link from the generic 583.Pa ntpkey_iff_ Ns Ar alice 584to this file. 585If there are no hosts restricted to operate only as clients, 586there is nothing further to do. 587As the IFF scheme is independent 588of keys and certificates, these files can be refreshed as needed. 589.Pp 590If a rogue client has the parameter file, it could masquerade 591as a legitimate server and present a middleman threat. 592To eliminate this threat, the client keys can be extracted 593from the parameter file and distributed to all restricted clients. 594After generating the parameter file, on alice run 595.Nm 596.Fl e 597and pipe the output to a file or mail program. 598Copy or mail this file to all restricted clients. 599On these clients install a soft link from the generic 600.Pa ntpkey_iff_ Ns Ar alice 601to this file. 602To further protect the integrity of the keys, 603each file can be encrypted with a secret password. 604.Pp 605For the GQ scheme proceed as in the TC scheme to generate keys 606and certificates for all group hosts, then for every trusted host 607in the group, generate the IFF parameter file. 608On trusted host alice run 609.Nm 610.Fl T 611.Fl G 612.Fl p Ar password 613to produce her parameter file 614.Pa ntpkey_GQpar_ Ns Ar alice.filestamp , 615which includes both server and client keys. 616Copy this file to all group hosts and install a soft link 617from the generic 618.Pa ntpkey_gq_ Ns Ar alice 619to this file. 620In addition, on each host bob install a soft link 621from generic 622.Pa ntpkey_gq_ Ns Ar bob 623to this file. 624As the GQ scheme updates the GQ parameters file and certificate 625at the same time, keys and certificates can be regenerated as needed. 626.Pp 627For the MV scheme, proceed as in the TC scheme to generate keys 628and certificates for all group hosts. 629For illustration assume trish is the TA, alice one of several trusted hosts 630and bob one of her clients. 631On TA trish run 632.Nm 633.Fl V Ar n 634.Fl p Ar password , 635where 636.Ar n 637is the number of revokable keys (typically 5) to produce 638the parameter file 639.Pa ntpkeys_MVpar_ Ns Ar trish.filestamp 640and client key files 641.Pa ntpkeys_MVkeyd_ Ns Ar trish.filestamp 642where 643.Ar d 644is the key number (0 \&< 645.Ar d 646\&< 647.Ar n ) . 648Copy the parameter file to alice and install a soft link 649from the generic 650.Pa ntpkey_mv_ Ns Ar alice 651to this file. 652Copy one of the client key files to alice for later distribution 653to her clients. 654It doesn't matter which client key file goes to alice, 655since they all work the same way. 656Alice copies the client key file to all of her cliens. 657On client bob install a soft link from generic 658.Pa ntpkey_mvkey_ Ns Ar bob 659to the client key file. 660As the MV scheme is independent of keys and certificates, 661these files can be refreshed as needed. 662.Ss Command Line Options 663.Bl -tag -width indent 664.It Fl c Ar scheme 665Select certificate message digest/signature encryption scheme. 666The 667.Ar scheme 668can be one of the following: 669. Cm RSA\-MD2 , RSA\-MD5 , RSA\-SHA , RSA\-SHA1 , RSA\-MDC2 , RSA\-RIPEMD160 , DSA\-SHA , 670or 671.Cm DSA\-SHA1 . 672Note that RSA schemes must be used with a RSA sign key and DSA 673schemes must be used with a DSA sign key. 674The default without this option is 675.Cm RSA\-MD5 . 676.It Fl d 677Enable debugging. 678This option displays the cryptographic data produced in eye\-friendly billboards. 679.It Fl e 680Write the IFF client keys to the standard output. 681This is intended for automatic key distribution by mail. 682.It Fl G 683Generate parameters and keys for the GQ identification scheme, 684obsoleting any that may exist. 685.It Fl g 686Generate keys for the GQ identification scheme 687using the existing GQ parameters. 688If the GQ parameters do not yet exist, create them first. 689.It Fl H 690Generate new host keys, obsoleting any that may exist. 691.It Fl I 692Generate parameters for the IFF identification scheme, 693obsoleting any that may exist. 694.It Fl i Ar name 695Set the suject name to 696.Ar name . 697This is used as the subject field in certificates 698and in the file name for host and sign keys. 699.It Fl M 700Generate MD5 keys, obsoleting any that may exist. 701.It Fl P 702Generate a private certificate. 703By default, the program generates public certificates. 704.It Fl p Ar password 705Encrypt generated files containing private data with 706.Ar password 707and the DES\-CBC algorithm. 708.It Fl q 709Set the password for reading files to password. 710.It Fl S Oo Cm RSA | DSA Oc 711Generate a new sign key of the designated type, 712obsoleting any that may exist. 713By default, the program uses the host key as the sign key. 714.It Fl s Ar name 715Set the issuer name to 716.Ar name . 717This is used for the issuer field in certificates 718and in the file name for identity files. 719.It Fl T 720Generate a trusted certificate. 721By default, the program generates a non\-trusted certificate. 722.It Fl V Ar nkeys 723Generate parameters and keys for the Mu\-Varadharajan (MV) identification scheme. 724.El 725.Ss Random Seed File 726All cryptographically sound key generation schemes must have means 727to randomize the entropy seed used to initialize 728the internal pseudo\-random number generator used 729by the library routines. 730The OpenSSL library uses a designated random seed file for this purpose. 731The file must be available when starting the NTP daemon and 732.Nm 733program. 734If a site supports OpenSSL or its companion OpenSSH, 735it is very likely that means to do this are already available. 736.Pp 737It is important to understand that entropy must be evolved 738for each generation, for otherwise the random number sequence 739would be predictable. 740Various means dependent on external events, such as keystroke intervals, 741can be used to do this and some systems have built\-in entropy sources. 742Suitable means are described in the OpenSSL software documentation, 743but are outside the scope of this page. 744.Pp 745The entropy seed used by the OpenSSL library is contained in a file, 746usually called 747.Cm .rnd , 748which must be available when starting the NTP daemon 749or the 750.Nm 751program. 752The NTP daemon will first look for the file 753using the path specified by the 754.Ic randfile 755subcommand of the 756.Ic crypto 757configuration command. 758If not specified in this way, or when starting the 759.Nm 760program, 761the OpenSSL library will look for the file using the path specified 762by the 763.Ev RANDFILE 764environment variable in the user home directory, 765whether root or some other user. 766If the 767.Ev RANDFILE 768environment variable is not present, 769the library will look for the 770.Cm .rnd 771file in the user home directory. 772If the file is not available or cannot be written, 773the daemon exits with a message to the system log and the program 774exits with a suitable error message. 775.Ss Cryptographic Data Files 776All other file formats begin with two lines. 777The first contains the file name, including the generated host name 778and filestamp. 779The second contains the datestamp in conventional Unix date format. 780Lines beginning with # are considered comments and ignored by the 781.Nm 782program and 783.Xr ntpd 1ntpdmdoc 784daemon. 785Cryptographic values are encoded first using ASN.1 rules, 786then encrypted if necessary, and finally written PEM\-encoded 787printable ASCII format preceded and followed by MIME content identifier lines. 788.Pp 789The format of the symmetric keys file is somewhat different 790than the other files in the interest of backward compatibility. 791Since DES\-CBC is deprecated in NTPv4, the only key format of interest 792is MD5 alphanumeric strings. 793Following hte heard the keys are 794entered one per line in the format 795.D1 Ar keyno type key 796where 797.Ar keyno 798is a positive integer in the range 1\-65,535, 799.Ar type 800is the string MD5 defining the key format and 801.Ar key 802is the key itself, 803which is a printable ASCII string 16 characters or less in length. 804Each character is chosen from the 93 printable characters 805in the range 0x21 through 0x7f excluding space and the 806.Ql # 807character. 808.Pp 809Note that the keys used by the 810.Xr ntpq 1ntpqmdoc 811and 812.Xr ntpdc 1ntpdcmdoc 813programs 814are checked against passwords requested by the programs 815and entered by hand, so it is generally appropriate to specify these keys 816in human readable ASCII format. 817.Pp 818The 819.Nm 820program generates a MD5 symmetric keys file 821.Pa ntpkey_MD5key_ Ns Ar hostname.filestamp . 822Since the file contains private shared keys, 823it should be visible only to root and distributed by secure means 824to other subnet hosts. 825The NTP daemon loads the file 826.Pa ntp.keys , 827so 828.Nm 829installs a soft link from this name to the generated file. 830Subsequently, similar soft links must be installed by manual 831or automated means on the other subnet hosts. 832While this file is not used with the Autokey Version 2 protocol, 833it is needed to authenticate some remote configuration commands 834used by the 835.Xr ntpq 1ntpqmdoc 836and 837.Xr ntpdc 1ntpdcmdoc 838utilities. 839.Sh "OPTIONS" 840.Bl -tag 841.It Fl b Ar imbits , Fl \-imbits Ns = Ns Ar imbits 842identity modulus bits. 843This option takes an integer number as its argument. 844The value of 845.Ar imbits 846is constrained to being: 847.in +4 848.nf 849.na 850in the range 256 through 2048 851.fi 852.in -4 853.sp 854The number of bits in the identity modulus. The default is 256. 855.It Fl c Ar scheme , Fl \-certificate Ns = Ns Ar scheme 856certificate scheme. 857.sp 858scheme is one of 859RSA\-MD2, RSA\-MD5, RSA\-SHA, RSA\-SHA1, RSA\-MDC2, RSA\-RIPEMD160, 860DSA\-SHA, or DSA\-SHA1. 861.sp 862Select the certificate message digest/signature encryption scheme. 863Note that RSA schemes must be used with a RSA sign key and DSA 864schemes must be used with a DSA sign key. The default without 865this option is RSA\-MD5. 866.It Fl C Ar cipher , Fl \-cipher Ns = Ns Ar cipher 867privatekey cipher. 868.sp 869Select the cipher which is used to encrypt the files containing 870private keys. The default is three\-key triple DES in CBC mode, 871equivalent to "@code{\-C des\-ede3\-cbc". The openssl tool lists ciphers 872available in "\fBopenssl \-h\fP" output. 873.It Fl d , Fl \-debug\-level 874Increase debug verbosity level. 875This option may appear an unlimited number of times. 876.sp 877.It Fl D Ar number , Fl \-set\-debug\-level Ns = Ns Ar number 878Set the debug verbosity level. 879This option may appear an unlimited number of times. 880This option takes an integer number as its argument. 881.sp 882.It Fl e , Fl \-id\-key 883Write IFF or GQ identity keys. 884.sp 885Write the IFF or GQ client keys to the standard output. This is 886intended for automatic key distribution by mail. 887.It Fl G , Fl \-gq\-params 888Generate GQ parameters and keys. 889.sp 890Generate parameters and keys for the GQ identification scheme, 891obsoleting any that may exist. 892.It Fl H , Fl \-host\-key 893generate RSA host key. 894.sp 895Generate new host keys, obsoleting any that may exist. 896.It Fl I , Fl \-iffkey 897generate IFF parameters. 898.sp 899Generate parameters for the IFF identification scheme, obsoleting 900any that may exist. 901.It Fl i Ar group , Fl \-ident Ns = Ns Ar group 902set Autokey group name. 903.sp 904Set the optional Autokey group name to name. This is used in 905the file name of IFF, GQ, and MV client parameters files. In 906that role, the default is the host name if this option is not 907provided. The group name, if specified using \fB\-i/\-\-ident\fP or 908using \fB\-s/\-\-subject\-name\fP following an '\fB@\fP' character, 909is also a part of the self\-signed host certificate's subject and 910issuer names in the form \fBhost@group\fP and should match the 911\'\fBcrypto ident\fP' or '\fBserver ident\fP' configuration in 912\fBntpd\fP's configuration file. 913.It Fl l Ar lifetime , Fl \-lifetime Ns = Ns Ar lifetime 914set certificate lifetime. 915This option takes an integer number as its argument. 916.sp 917Set the certificate expiration to lifetime days from now. 918.It Fl M , Fl \-md5key 919generate MD5 keys. 920.sp 921Generate MD5 keys, obsoleting any that may exist. 922.It Fl m Ar modulus , Fl \-modulus Ns = Ns Ar modulus 923modulus. 924This option takes an integer number as its argument. 925The value of 926.Ar modulus 927is constrained to being: 928.in +4 929.nf 930.na 931in the range 256 through 2048 932.fi 933.in -4 934.sp 935The number of bits in the prime modulus. The default is 512. 936.It Fl P , Fl \-pvt\-cert 937generate PC private certificate. 938.sp 939Generate a private certificate. By default, the program generates 940public certificates. 941.It Fl p Ar passwd , Fl \-password Ns = Ns Ar passwd 942local private password. 943.sp 944Local files containing private data are encrypted with the 945DES\-CBC algorithm and the specified password. The same password 946must be specified to the local ntpd via the "crypto pw password" 947configuration command. The default password is the local 948hostname. 949.It Fl q Ar passwd , Fl \-export\-passwd Ns = Ns Ar passwd 950export IFF or GQ group keys with password. 951.sp 952Export IFF or GQ identity group keys to the standard output, 953encrypted with the DES\-CBC algorithm and the specified password. 954The same password must be specified to the remote ntpd via the 955"crypto pw password" configuration command. See also the option 956-\-id\-key (\-e) for unencrypted exports. 957.It Fl S Ar sign , Fl \-sign\-key Ns = Ns Ar sign 958generate sign key (RSA or DSA). 959.sp 960Generate a new sign key of the designated type, obsoleting any 961that may exist. By default, the program uses the host key as the 962sign key. 963.It Fl s Ar host@group , Fl \-subject\-name Ns = Ns Ar host@group 964set host and optionally group name. 965.sp 966Set the Autokey host name, and optionally, group name specified 967following an '\fB@\fP' character. The host name is used in the file 968name of generated host and signing certificates, without the 969group name. The host name, and if provided, group name are used 970in \fBhost@group\fP form for the host certificate's subject and issuer 971fields. Specifying '\fB\-s @group\fP' is allowed, and results in 972leaving the host name unchanged while appending \fB@group\fP to the 973subject and issuer fields, as with \fB\-i group\fP. The group name, or 974if not provided, the host name are also used in the file names 975of IFF, GQ, and MV client parameter files. 976.It Fl T , Fl \-trusted\-cert 977trusted certificate (TC scheme). 978.sp 979Generate a trusted certificate. By default, the program generates 980a non\-trusted certificate. 981.It Fl V Ar num , Fl \-mv\-params Ns = Ns Ar num 982generate <num> MV parameters. 983This option takes an integer number as its argument. 984.sp 985Generate parameters and keys for the Mu\-Varadharajan (MV) 986identification scheme. 987.It Fl v Ar num , Fl \-mv\-keys Ns = Ns Ar num 988update <num> MV keys. 989This option takes an integer number as its argument. 990.sp 991This option has not been fully documented. 992.It Fl \&? , Fl \-help 993Display usage information and exit. 994.It Fl \&! , Fl \-more\-help 995Pass the extended usage information through a pager. 996.It Fl > Oo Ar cfgfile Oc , Fl \-save\-opts Oo Ns = Ns Ar cfgfile Oc 997Save the option state to \fIcfgfile\fP. The default is the \fIlast\fP 998configuration file listed in the \fBOPTION PRESETS\fP section, below. 999The command will exit after updating the config file. 1000.It Fl < Ar cfgfile , Fl \-load\-opts Ns = Ns Ar cfgfile , Fl \-no\-load\-opts 1001Load options from \fIcfgfile\fP. 1002The \fIno\-load\-opts\fP form will disable the loading 1003of earlier config/rc/ini files. \fI\-\-no\-load\-opts\fP is handled early, 1004out of order. 1005.It Fl \-version Op Brq Ar v|c|n 1006Output version of program and exit. The default mode is `v', a simple 1007version. The `c' mode will print copyright information and `n' will 1008print the full copyright notice. 1009.El 1010.Sh "OPTION PRESETS" 1011Any option that is not marked as \fInot presettable\fP may be preset 1012by loading values from configuration ("RC" or ".INI") file(s) and values from 1013environment variables named: 1014.nf 1015 \fBNTP_KEYGEN_<option\-name>\fP or \fBNTP_KEYGEN\fP 1016.fi 1017.ad 1018The environmental presets take precedence (are processed later than) 1019the configuration files. 1020The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP". 1021If any of these are directories, then the file \fI.ntprc\fP 1022is searched for within those directories. 1023.Sh USAGE 1024The 1025.Fl p Ar password 1026option specifies the write password and 1027.Fl q Ar password 1028option the read password for previously encrypted files. 1029The 1030.Nm 1031program prompts for the password if it reads an encrypted file 1032and the password is missing or incorrect. 1033If an encrypted file is read successfully and 1034no write password is specified, the read password is used 1035as the write password by default. 1036.Sh "ENVIRONMENT" 1037See \fBOPTION PRESETS\fP for configuration environment variables. 1038.Sh "FILES" 1039See \fBOPTION PRESETS\fP for configuration files. 1040.Sh "EXIT STATUS" 1041One of the following exit values will be returned: 1042.Bl -tag 1043.It 0 " (EXIT_SUCCESS)" 1044Successful program execution. 1045.It 1 " (EXIT_FAILURE)" 1046The operation failed or the command syntax was not valid. 1047.It 66 " (EX_NOINPUT)" 1048A specified configuration file could not be loaded. 1049.It 70 " (EX_SOFTWARE)" 1050libopts had an internal operational error. Please report 1051it to autogen\-users@lists.sourceforge.net. Thank you. 1052.El 1053.Sh "AUTHORS" 1054The University of Delaware and Network Time Foundation 1055.Sh "COPYRIGHT" 1056Copyright (C) 1992\-2016 The University of Delaware and Network Time Foundation all rights reserved. 1057This program is released under the terms of the NTP license, <http://ntp.org/license>. 1058.Sh BUGS 1059It can take quite a while to generate some cryptographic values, 1060from one to several minutes with modern architectures 1061such as UltraSPARC and up to tens of minutes to an hour 1062with older architectures such as SPARC IPC. 1063.Pp 1064Please report bugs to http://bugs.ntp.org . 1065.Pp 1066Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org 1067.Sh NOTES 1068Portions of this document came from FreeBSD. 1069.Pp 1070This manual page was \fIAutoGen\fP\-erated from the \fBntp\-keygen\fP 1071option definitions. 1072