{ "content": [ { "type": "text", "text": "# ntp-keygen(8) (man)\n\n**Summary:** ntp-keygen — Create a NTP host key\n\n**Synopsis:** ntp-keygen [-flags] [-flag [value]] [--option-name[[=| ]value]]\nAll arguments must be options.\n\n## Flags\n\n| Flag | Long | Arg | Description |\n|------|------|-----|-------------|\n| -b | --imbits | — | identity modulus bits. This option takes an integer number as its argument. The value of imbits is constrained to being: |\n| -c | --certificate | — | certificate scheme. scheme is one of RSA-MD2, RSA-MD5, RSA-MDC2, RSA-SHA, RSA-SHA1, RSA-RIPEMD160, DSA-SHA, or DSA-SHA1. |\n| -C | --cipher | — | privatekey cipher. Select the cipher which is used to encrypt the files containing private keys. The de‐ fault is three- |\n| -d | --debug-level | — | Increase debug verbosity level. This option may appear an unlimited number of times. |\n| -D | --set-debug-level | — | Set the debug verbosity level. This option may appear an unlimited number of times. This option takes an integer number |\n| -e | --id-key | — | Write IFF or GQ identity keys. Write the public parameters from the IFF or GQ client keys to the standard output. This i |\n| -G | --gq-params | — | Generate GQ parameters and keys. Generate parameters and keys for the GQ identification scheme, obsoleting any that may |\n| -H | --host-key | — | generate RSA host key. Generate new host keys, obsoleting any that may exist. |\n| -I | --iffkey | — | generate IFF parameters. Generate parameters for the IFF identification scheme, obsoleting any that may exist. |\n| -i | --ident | — | set Autokey group name. Set the optional Autokey group name to name. This is used in the file name of IFF, GQ, and MV cl |\n| -l | --lifetime | — | set certificate lifetime. This option takes an integer number as its argument. Set the certificate expiration to lifetim |\n| -m | --modulus | — | prime modulus. This option takes an integer number as its argument. The value of modulus is constrained to being: in the |\n| -M | --md5key | — | generate symmetric keys. Generate symmetric keys, obsoleting any that may exist. |\n| -P | --pvt-cert | — | generate PC private certificate. Generate a private certificate. By default, the program generates public certificates. |\n| -p | --password | — | local private password. Local files containing private data are encrypted with the DES-CBC algorithm and the specified p |\n| -q | --export-passwd | — | export IFF or GQ group keys with password. Export IFF or GQ identity group keys to the standard output, encrypted with t |\n| -s | --subject-name | — | set host and optionally group name. Set the Autokey host name, and optionally, group name specified following an '@' cha |\n| -S | --sign-key | — | generate sign key (RSA or DSA). Generate a new sign key of the designated type, obsoleting any that may exist. By de‐ fa |\n| -T | --trusted-cert | — | trusted certificate (TC scheme). Generate a trusted certificate. By default, the program generates a non-trusted cer‐ ti |\n| -V | --mv-params | — | generate MV parameters. This option takes an integer number as its argument. Generate parameters and keys for the |\n| -v | --mv-keys | — | update MV keys. This option takes an integer number as its argument. This option has not been fully documented. -? |\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **SYNOPSIS** (4 lines)\n- **DESCRIPTION** (55 lines) — 26 subsections\n - Running the Program (101 lines)\n - Trusted Hosts and Groups (32 lines)\n - Identity Schemes (63 lines)\n - Command Line Options (1 lines)\n - -b --imbits (6 lines)\n - -c --certificate (7 lines)\n - -C --cipher (4 lines)\n - -d --debug-level (3 lines)\n - -D --set-debug-level (3 lines)\n - -e --id-key (4 lines)\n - -G --gq-params (3 lines)\n - -H --host-key (2 lines)\n - -I --iffkey (3 lines)\n - -i --ident (7 lines)\n - -l --lifetime (3 lines)\n - -m --modulus (5 lines)\n - -M --md5key (6 lines)\n - -p --password (4 lines)\n - -P --pvt-cert (4 lines)\n - -q --export-passwd (5 lines)\n - -s --subject-key (8 lines)\n - -S --sign-key (4 lines)\n - -T --trusted-cert (3 lines)\n - -V --mv-params (4 lines)\n - Random Seed File (24 lines)\n - Cryptographic Data Files (66 lines)\n- **OPTIONS** (1 lines) — 21 subsections\n - -b --imbits (6 lines)\n - -c --certificate (9 lines)\n - -C --cipher (6 lines)\n - -d --debug-level (3 lines)\n - -D --set-debug-level (4 lines)\n - -e --id-key (5 lines)\n - -G --gq-params (5 lines)\n - -H --host-key (4 lines)\n - -I --iffkey (4 lines)\n - -i --ident (9 lines)\n - -l --lifetime (4 lines)\n - -m --modulus (6 lines)\n - -M --md5key (4 lines)\n - -P --pvt-cert (4 lines)\n - -p --password (7 lines)\n - -q --export-passwd (7 lines)\n - -s --subject-name (11 lines)\n - -S --sign-key (5 lines)\n - -T --trusted-cert (5 lines)\n - -V --mv-params (4 lines)\n - -v --mv-keys (23 lines)\n- **OPTION PRESETS** (7 lines)\n- **USAGE** (1 lines)\n- **ENVIRONMENT** (2 lines)\n- **FILES** (2 lines)\n- **EXIT STATUS** (15 lines)\n- **AUTHORS** (2 lines)\n- **COPYRIGHT** (3 lines)\n- **BUGS** (6 lines)\n- **NOTES** (5 lines)\n\n## Full Content\n\n### NAME\n\nntp-keygen — Create a NTP host key\n\n### SYNOPSIS\n\nntp-keygen [-flags] [-flag [value]] [--option-name[[=| ]value]]\n\nAll arguments must be options.\n\n### DESCRIPTION\n\nThis program generates cryptographic data files used by the NTPv4 authentication and identifi‐\ncation schemes. It can generate message digest keys used in symmetric key cryptography and, if\nthe OpenSSL software library has been installed, it can generate host keys, signing keys, cer‐\ntificates, and identity keys and parameters used in Autokey public key cryptography. These\nfiles are used for cookie encryption, digital signature, and challenge/response identification\nalgorithms compatible with the Internet standard security infrastructure.\n\nThe message digest symmetric keys file is generated in a format compatible with NTPv3. All\nother files are in PEM-encoded printable ASCII format, so they can be embedded as MIME attach‐\nments in email to other sites and certificate authorities. By default, files are not en‐\ncrypted.\n\nWhen used to generate message digest symmetric keys, the program produces a file containing ten\npseudo-random printable ASCII strings suitable for the MD5 message digest algorithm included in\nthe distribution. If the OpenSSL library is installed, it produces an additional ten hex-en‐\ncoded random bit strings suitable for SHA1, AES-128-CMAC, and other message digest algorithms.\nThe message digest symmetric keys file must be distributed and stored using secure means beyond\nthe scope of NTP itself. Besides the keys used for ordinary NTP associations, additional keys\ncan be defined as passwords for the ntpq(1) and ntpdc(1) utility programs.\n\nThe remaining generated files are compatible with other OpenSSL applications and other Public\nKey Infrastructure (PKI) resources. Certificates generated by this program are compatible with\nextant industry practice, although some users might find the interpretation of X509v3 extension\nfields somewhat liberal. However, the identity keys are probably not compatible with anything\nother than Autokey.\n\nSome files used by this program are encrypted using a private password. The -p option speci‐\nfies the read password for local encrypted files and the -q option the write password for en‐\ncrypted files sent to remote sites. If no password is specified, the host name returned by the\nUnix hostname(1) command, normally the DNS name of the host, is used as the the default read\npassword, for convenience. The ntp-keygen program prompts for the password if it reads an en‐\ncrypted file and the password is missing or incorrect. If an encrypted file is read success‐\nfully and no write password is specified, the read password is used as the write password by\ndefault.\n\nThe pw option of the crypto ntpd(8) configuration command specifies the read password for pre‐\nviously encrypted local files. This must match the local read password used by this program.\nIf not specified, the host name is used. Thus, if files are generated by this program without\nan explicit password, they can be read back by ntpd(8) without specifying an explicit password\nbut only on the same host. If the write password used for encryption is specified as the host\nname, these files can be read by that host with no explicit password.\n\nNormally, encrypted files for each host are generated by that host and used only by that host,\nalthough exceptions exist as noted later on this page. The symmetric keys file, normally\ncalled ntp.keys, is usually installed in /etc. Other files and links are usually installed in\n/usr/local/etc, which is normally in a shared filesystem in NFS-mounted networks and cannot be\nchanged by shared clients. In these cases, NFS clients can specify the files in another direc‐\ntory such as /etc using the keysdir ntpd(8) configuration file command.\n\nThis program directs commentary and error messages to the standard error stream stderr and re‐\nmote files to the standard output stream stdout where they can be piped to other applications\nor redirected to files. The names used for generated files and links all begin with the string\nntpkey* and include the file type, generating host and filestamp, as described in the\nCryptographic Data Files section below.\n\n#### Running the Program\n\nThe safest way to run the ntp-keygen program is logged in directly as root. The recommended\nprocedure is change to the keys directory, usually /usr/local/etc, then run the program.\n\nTo test and gain experience with Autokey concepts, log in as root and change to the keys direc‐\ntory, usually /usr/local/etc. When run for the first time, or if all files with names begin‐\nning with ntpkey* have been removed, use the ntp-keygen command without arguments to generate a\ndefault RSA host key and matching RSA-MD5 certificate file with expiration date one year hence,\nwhich is all that is necessary in many cases. The program also generates soft links from the\ngeneric names to the respective files. If run again without options, the program uses the ex‐\nisting keys and parameters and generates a new certificate file with new expiration date one\nyear hence, and soft link.\n\nThe host key is used to encrypt the cookie when required and so must be RSA type. By default,\nthe host key is also the sign key used to encrypt signatures. When necessary, a different sign\nkey can be specified and this can be either RSA or DSA type. By default, the message digest\ntype is MD5, but any combination of sign key type and message digest type supported by the\nOpenSSL library can be specified, including those using the AES128CMAC, MD2, MD5, MDC2, SHA,\nSHA1 and RIPE160 message digest algorithms. However, the scheme specified in the certificate\nmust be compatible with the sign key. Certificates using any digest algorithm are compatible\nwith RSA sign keys; however, only SHA and SHA1 certificates are compatible with DSA sign keys.\n\nPrivate/public key files and certificates are compatible with other OpenSSL applications and\nvery likely other libraries as well. Certificates or certificate requests derived from them\nshould be compatible with extant industry practice, although some users might find the inter‐\npretation of X509v3 extension fields somewhat liberal. However, the identification parameter\nfiles, although encoded as the other files, are probably not compatible with anything other\nthan Autokey.\n\nRunning the program as other than root and using the Unix su(1) command to assume root may not\nwork properly, since by default the OpenSSL library looks for the random seed file .rnd in the\nuser home directory. However, there should be only one .rnd, most conveniently in the root di‐\nrectory, so it is convenient to define the RANDFILE environment variable used by the OpenSSL\nlibrary as the path to .rnd.\n\nInstalling the keys as root might not work in NFS-mounted shared file systems, as NFS clients\nmay not be able to write to the shared keys directory, even as root. In this case, NFS clients\ncan specify the files in another directory such as /etc using the keysdir ntpd(8) configuration\nfile command. There is no need for one client to read the keys and certificates of other\nclients or servers, as these data are obtained automatically by the Autokey protocol.\n\nOrdinarily, cryptographic files are generated by the host that uses them, but it is possible\nfor a trusted agent (TA) to generate these files for other hosts; however, in such cases files\nshould always be encrypted. The subject name and trusted name default to the hostname of the\nhost generating the files, but can be changed by command line options. It is convenient to\ndesignate the owner name and trusted name as the subject and issuer fields, respectively, of\nthe certificate. The owner name is also used for the host and sign key files, while the\ntrusted name is used for the identity files.\n\nAll files are installed by default in the keys directory /usr/local/etc, which is normally in a\nshared filesystem in NFS-mounted networks. The actual location of the keys directory and each\nfile can be overridden by configuration commands, but this is not recommended. Normally, the\nfiles for each host are generated by that host and used only by that host, although exceptions\nexist as noted later on this page.\n\nNormally, files containing private values, including the host key, sign key and identification\nparameters, are permitted root read/write-only; while others containing public values are per‐\nmitted world readable. Alternatively, files containing private values can be encrypted and\nthese files permitted world readable, which simplifies maintenance in shared file systems.\nSince uniqueness is insured by the hostname and filestamp file name extensions, the files for\nan NTP server and dependent clients can all be installed in the same shared directory.\n\nThe recommended practice is to keep the file name extensions when installing a file and to in‐\nstall a soft link from the generic names specified elsewhere on this page to the generated\nfiles. This allows new file generations to be activated simply by changing the link. If a\nlink is present, ntpd(8) follows it to the file name to extract the filestamp. If a link is\nnot present, ntpd(8) extracts the filestamp from the file itself. This allows clients to ver‐\nify that the file and generation times are always current. The ntp-keygen program uses the\nsame filestamp extension for all files generated at one time, so each generation is distinct\nand can be readily recognized in monitoring data.\n\nRun the command on as many hosts as necessary. Designate one of them as the trusted host (TH)\nusing ntp-keygen with the -T option and configure it to synchronize from reliable Internet\nservers. Then configure the other hosts to synchronize to the TH directly or indirectly. A\ncertificate trail is created when Autokey asks the immediately ascendant host towards the TH to\nsign its certificate, which is then provided to the immediately descendant host on request.\nAll group hosts should have acyclic certificate trails ending on the TH.\n\nThe host key is used to encrypt the cookie when required and so must be RSA type. By default,\nthe host key is also the sign key used to encrypt signatures. A different sign key can be as‐\nsigned using the -S option and this can be either RSA or DSA type. By default, the signature\nmessage digest type is MD5, but any combination of sign key type and message digest type sup‐\nported by the OpenSSL library can be specified using the -c option.\n\nThe rules say cryptographic media should be generated with proventic filestamps, which means\nthe host should already be synchronized before this program is run. This of course creates a\nchicken-and-egg problem when the host is started for the first time. Accordingly, the host\ntime should be set by some other means, such as eyeball-and-wristwatch, at least so that the\ncertificate lifetime is within the current year. After that and when the host is synchronized\nto a proventic source, the certificate should be re-generated.\n\nAdditional information on trusted groups and identity schemes is on the “Autokey Public-Key\nAuthentication” page.\n\nFile names begin with the prefix ntpkey and end with the suffix hostname. filestamp, where\nhostname is the owner name, usually the string returned by the Unix hostname(1) command, and\nfilestamp is the NTP seconds when the file was generated, in decimal digits. This both guaran‐\ntees uniqueness and simplifies maintenance procedures, since all files can be quickly removed\nby a rm ntpkey* command or all files generated at a specific time can be removed by a rm\n*filestamp command. To further reduce the risk of misconfiguration, the first two lines of a\nfile contain the file name and generation date and time as comments.\n\n#### Trusted Hosts and Groups\n\nEach cryptographic configuration involves selection of a signature scheme and identification\nscheme, called a cryptotype, as explained in the Authentication Options section of ntp.conf(5).\nThe default cryptotype uses RSA encryption, MD5 message digest and TC identification. First,\nconfigure a NTP subnet including one or more low-stratum trusted hosts from which all other\nhosts derive synchronization directly or indirectly. Trusted hosts have trusted certificates;\nall other hosts have nontrusted certificates. These hosts will automatically and dynamically\nbuild authoritative certificate trails to one or more trusted hosts. A trusted group is the\nset of all hosts that have, directly or indirectly, a certificate trail ending at a trusted\nhost. The trail is defined by static configuration file entries or dynamic means described on\nthe Automatic NTP Configuration Options section of ntp.conf(5).\n\nOn each trusted host as root, change to the keys directory. To insure a fresh fileset, remove\nall ntpkey files. Then run ntp-keygen -T to generate keys and a trusted certificate. On all\nother hosts do the same, but leave off the -T flag to generate keys and nontrusted certifi‐\ncates. When complete, start the NTP daemons beginning at the lowest stratum and working up the\ntree. It may take some time for Autokey to instantiate the certificate trails throughout the\nsubnet, but setting up the environment is completely automatic.\n\nIf it is necessary to use a different sign key or different digest/signature scheme than the\ndefault, run ntp-keygen with the -S type option, where type is either RSA or DSA. The most\nfrequent need to do this is when a DSA-signed certificate is used. If it is necessary to use a\ndifferent certificate scheme than the default, run ntp-keygen with the -c scheme option and se‐\nlected scheme as needed. If ntp-keygen is run again without these options, it generates a new\ncertificate using the same scheme and sign key, and soft link.\n\nAfter setting up the environment it is advisable to update certificates from time to time, if\nonly to extend the validity interval. Simply run ntp-keygen with the same flags as before to\ngenerate new certificates using existing keys, and soft links. However, if the host or sign\nkey is changed, ntpd(8) should be restarted. When ntpd(8) is restarted, it loads any new files\nand restarts the protocol. Other dependent hosts will continue as usual until signatures are\nrefreshed, at which time the protocol is restarted.\n\n#### Identity Schemes\n\nAs mentioned on the Autonomous Authentication page, the default TC identity scheme is vulnera‐\nble to a middleman attack. However, there are more secure identity schemes available, includ‐\ning PC, IFF, GQ and MV schemes described below. These schemes are based on a TA, one or more\ntrusted hosts and some number of nontrusted hosts. Trusted hosts prove identity using values\nprovided by the TA, while the remaining hosts prove identity using values provided by a trusted\nhost and certificate trails that end on that host. The name of a trusted host is also the name\nof its sugroup and also the subject and issuer name on its trusted certificate. The TA is not\nnecessarily a trusted host in this sense, but often is.\n\nIn some schemes there are separate keys for servers and clients. A server can also be a client\nof another server, but a client can never be a server for another client. In general, trusted\nhosts and nontrusted hosts that operate as both server and client have parameter files that\ncontain both server and client keys. Hosts that operate only as clients have key files that\ncontain only client keys.\n\nThe PC scheme supports only one trusted host in the group. On trusted host alice run\nntp-keygen -P -p password to generate the host key file ntpkey RSA keyalice. filestamp and\ntrusted private certificate file ntpkey RSA-MD5 certalice. filestamp, and soft links. Copy\nboth files to all group hosts; they replace the files which would be generated in other\nschemes. On each host bob install a soft link from the generic name ntpkeyhostbob to the\nhost key file and soft link ntpkeycertbob to the private certificate file. Note the generic\nlinks are on bob, but point to files generated by trusted host alice. In this scheme it is not\npossible to refresh either the keys or certificates without copying them to all other hosts in\nthe group, and recreating the soft links.\n\nFor the IFF scheme proceed as in the TC scheme to generate keys and certificates for all group\nhosts, then for every trusted host in the group, generate the IFF parameter file. On trusted\nhost alice run ntp-keygen -T -I -p password to produce her parameter file\nntpkeyIFFparalice.filestamp, which includes both server and client keys. Copy this file to\nall group hosts that operate as both servers and clients and install a soft link from the\ngeneric ntpkeyiffalice to this file. If there are no hosts restricted to operate only as\nclients, there is nothing further to do. As the IFF scheme is independent of keys and certifi‐\ncates, these files can be refreshed as needed.\n\nIf a rogue client has the parameter file, it could masquerade as a legitimate server and\npresent a middleman threat. To eliminate this threat, the client keys can be extracted from\nthe parameter file and distributed to all restricted clients. After generating the parameter\nfile, on alice run ntp-keygen -e and pipe the output to a file or email program. Copy or email\nthis file to all restricted clients. On these clients install a soft link from the generic\nntpkeyiffalice to this file. To further protect the integrity of the keys, each file can be\nencrypted with a secret password.\n\nFor the GQ scheme proceed as in the TC scheme to generate keys and certificates for all group\nhosts, then for every trusted host in the group, generate the IFF parameter file. On trusted\nhost alice run ntp-keygen -T -G -p password to produce her parameter file\nntpkeyGQparalice.filestamp, which includes both server and client keys. Copy this file to\nall group hosts and install a soft link from the generic ntpkeygqalice to this file. In ad‐\ndition, on each host bob install a soft link from generic ntpkeygqbob to this file. As the\nGQ scheme updates the GQ parameters file and certificate at the same time, keys and certifi‐\ncates can be regenerated as needed.\n\nFor the MV scheme, proceed as in the TC scheme to generate keys and certificates for all group\nhosts. For illustration assume trish is the TA, alice one of several trusted hosts and bob one\nof her clients. On TA trish run ntp-keygen -V n -p password, where n is the number of revok‐\nable keys (typically 5) to produce the parameter file ntpkeysMVpartrish.filestamp and client\nkey files ntpkeysMVkeyd trish. filestamp where d is the key number (0 < d < n). Copy the\nparameter file to alice and install a soft link from the generic ntpkeymvalice to this file.\nCopy one of the client key files to alice for later distribution to her clients. It does not\nmatter which client key file goes to alice, since they all work the same way. Alice copies the\nclient key file to all of her clients. On client bob install a soft link from generic\nntpkeymvkeybob to the client key file. As the MV scheme is independent of keys and certifi‐\ncates, these files can be refreshed as needed.\n\n#### Command Line Options\n\n#### -b --imbits\n\nSet the number of bits in the identity modulus for generating identity keys to modulus\nbits. The number of bits in the identity modulus defaults to 256, but can be set to\nvalues from 256 to 2048 (32 to 256 octets). Use the larger moduli with caution, as\nthis can consume considerable computing resources and increases the size of authenti‐\ncated packets.\n\n#### -c --certificate\n\nSelect certificate signature encryption/message digest scheme. The scheme can be one\nof the following: RSA-MD2, RSA-MD5, RSA-MDC2, RSA-SHA, RSA-SHA1, RSA-RIPEMD160,\nDSA-SHA, or DSA-SHA1. Note that RSA schemes must be used with an RSA sign key and DSA\nschemes must be used with a DSA sign key. The default without this option is RSA-MD5.\nIf compatibility with FIPS 140-2 is required, either the DSA-SHA or DSA-SHA1 scheme\nmust be used.\n\n#### -C --cipher\n\nSelect the OpenSSL cipher to encrypt the files containing private keys. The default\nwithout this option is three-key triple DES in CBC mode, des-ede3-cbc. The openssl -h\ncommand provided with OpenSSL displays available ciphers.\n\n#### -d --debug-level\n\nIncrease debugging verbosity level. This option displays the cryptographic data pro‐\nduced in eye-friendly billboards.\n\n#### -D --set-debug-level\n\nSet the debugging verbosity to level. This option displays the cryptographic data pro‐\nduced in eye-friendly billboards.\n\n#### -e --id-key\n\nWrite the IFF or GQ public parameters from the IFFkey or GQkey client keys file previ‐\nously specified as unencrypted data to the standard output stream stdout. This is in‐\ntended for automatic key distribution by email.\n\n#### -G --gq-params\n\nGenerate a new encrypted GQ parameters and key file for the Guillou-Quisquater (GQ)\nidentity scheme. This option is mutually exclusive with the -I and -V options.\n\n#### -H --host-key\n\nGenerate a new encrypted RSA public/private host key file.\n\n#### -I --iffkey\n\nGenerate a new encrypted IFF key file for the Schnorr (IFF) identity scheme. This op‐\ntion is mutually exclusive with the -G and Fl V options.\n\n#### -i --ident\n\nSet the optional Autokey group name to group. This is used in the identity scheme pa‐\nrameter file names of IFF, GQ, and MV client parameters files. In that role, the de‐\nfault is the host name if no group is provided. The group name, if specified using -i\nor -s following an ‘@’ character, is also used in certificate subject and issuer names\nin the form host @ group and should match the group specified via crypto ident or\nserver ident in the ntpd configuration file.\n\n#### -l --lifetime\n\nSet the lifetime for certificate expiration to days. The default lifetime is one year\n(365 days).\n\n#### -m --modulus\n\nSet the number of bits in the prime modulus for generating files to bits. The modulus\ndefaults to 512, but can be set from 256 to 2048 (32 to 256 octets). Use the larger\nmoduli with caution, as this can consume considerable computing resources and increases\nthe size of authenticated packets.\n\n#### -M --md5key\n\nGenerate a new symmetric keys file containing 10 MD5 keys, and if OpenSSL is available,\n10 SHA keys. An MD5 key is a string of 20 random printable ASCII characters, while a\nSHA key is a string of 40 random hex digits. The file can be edited using a text edi‐\ntor to change the key type or key content. This option is mutually exclusive with all\nother options.\n\n#### -p --password\n\nSet the password for reading and writing encrypted files to passwd. These include the\nhost, sign and identify key files. By default, the password is the string returned by\nthe Unix hostname command.\n\n#### -P --pvt-cert\n\nGenerate a new private certificate used by the PC identity scheme. By default, the\nprogram generates public certificates. Note: the PC identity scheme is not recommended\nfor new installations.\n\n#### -q --export-passwd\n\nSet the password for writing encrypted IFF, GQ and MV identity files redirected to\nstdout to passwd. In effect, these files are decrypted with the -p password, then en‐\ncrypted with the -q password. By default, the password is the string returned by the\nUnix hostname command.\n\n#### -s --subject-key\n\nSpecify the Autokey host name, where host is the optional host name and group is the\noptional group name. The host name, and if provided, group name are used in host @\ngroup form as certificate subject and issuer. Specifying -s -@ group is allowed, and\nresults in leaving the host name unchanged, as with -i group. The group name, or if no\ngroup is provided, the host name are also used in the file names of IFF, GQ, and MV\nidentity scheme client parameter files. If host is not specified, the default host\nname is the string returned by the Unix hostname command.\n\n#### -S --sign-key\n\nGenerate a new encrypted public/private sign key file of the specified type. By de‐\nfault, the sign key is the host key and has the same type. If compatibility with FIPS\n140-2 is required, the sign key type must be DSA.\n\n#### -T --trusted-cert\n\nGenerate a trusted certificate. By default, the program generates a non-trusted cer‐\ntificate.\n\n#### -V --mv-params\n\nGenerate nkeys encrypted server keys and parameters for the Mu-Varadharajan (MV) iden‐\ntity scheme. This option is mutually exclusive with the -I and -G options. Note: sup‐\nport for this option should be considered a work in progress.\n\n#### Random Seed File\n\nAll cryptographically sound key generation schemes must have means to randomize the entropy\nseed used to initialize the internal pseudo-random number generator used by the library rou‐\ntines. The OpenSSL library uses a designated random seed file for this purpose. The file must\nbe available when starting the NTP daemon and ntp-keygen program. If a site supports OpenSSL\nor its companion OpenSSH, it is very likely that means to do this are already available.\n\nIt is important to understand that entropy must be evolved for each generation, for otherwise\nthe random number sequence would be predictable. Various means dependent on external events,\nsuch as keystroke intervals, can be used to do this and some systems have built-in entropy\nsources. Suitable means are described in the OpenSSL software documentation, but are outside\nthe scope of this page.\n\nThe entropy seed used by the OpenSSL library is contained in a file, usually called .rnd, which\nmust be available when starting the NTP daemon or the ntp-keygen program. The NTP daemon will\nfirst look for the file using the path specified by the randfile subcommand of the crypto con‐\nfiguration command. If not specified in this way, or when starting the ntp-keygen program, the\nOpenSSL library will look for the file using the path specified by the RANDFILE environment\nvariable in the user home directory, whether root or some other user. If the RANDFILE environ‐\nment variable is not present, the library will look for the .rnd file in the user home direc‐\ntory. Since both the ntp-keygen program and ntpd(8) daemon must run as root, the logical place\nto put this file is in /.rnd or /root/.rnd. If the file is not available or cannot be written,\nthe daemon exits with a message to the system log and the program exits with a suitable error\nmessage.\n\n#### Cryptographic Data Files\n\nAll file formats begin with two nonencrypted lines. The first line contains the file name, in‐\ncluding the generated host name and filestamp, in the format ntpkeykey name. filestamp,\nwhere key is the key or parameter type, name is the host or group name and filestamp is the\nfilestamp (NTP seconds) when the file was created. By convention, key names in generated file\nnames include both upper and lower case characters, while key names in generated link names in‐\nclude only lower case characters. The filestamp is not used in generated link names. The sec‐\nond line contains the datestamp in conventional Unix date format. Lines beginning with ‘#’ are\nconsidered comments and ignored by the ntp-keygen program and ntpd(8) daemon.\n\nThe remainder of the file contains cryptographic data, encoded first using ASN.1 rules, then\nencrypted if necessary, and finally written in PEM-encoded printable ASCII text, preceded and\nfollowed by MIME content identifier lines.\n\nThe format of the symmetric keys file, ordinarily named ntp.keys, is somewhat different than\nthe other files in the interest of backward compatibility. Ordinarily, the file is generated\nby this program, but it can be constructed and edited using an ordinary text editor.\n\n# ntpkeyMD5keybk.ntp.org.3595864945\n# Thu Dec 12 19:22:25 2013\n1 MD5 L\";Nw<`.Il0%XXK9O'51VwV MV parameters. This option takes an integer number as its argument.\n\nGenerate parameters and keys for the Mu-Varadharajan (MV) identification scheme.\n\n#### -v --mv-keys\n\nupdate MV keys. This option takes an integer number as its argument.\n\nThis option has not been fully documented.\n\n-?, --help\nDisplay usage information and exit.\n\n-!, --more-help\nPass the extended usage information through a pager.\n\n-> [cfgfile], --save-opts [=cfgfile]\nSave the option state to cfgfile. The default is the last configuration file listed in\nthe OPTION PRESETS section, below. The command will exit after updating the config\nfile.\n\n-< cfgfile, --load-opts=cfgfile, --no-load-opts\nLoad options from cfgfile. The no-load-opts form will disable the loading of earlier\nconfig/rc/ini files. --no-load-opts is handled early, out of order.\n\n--version [{v|c|n}]\nOutput version of program and exit. The default mode is `v', a simple version. The\n`c' mode will print copyright information and `n' will print the full copyright notice.\n\n### OPTION PRESETS\n\nAny option that is not marked as not presettable may be preset by loading values from configu‐\nration (\"RC\" or \".INI\") file(s) and values from environment variables named:\nNTPKEYGEN or NTPKEYGEN\nThe environmental presets take precedence (are processed later than) the configuration files.\nThe homerc files are \"$HOME\", and \".\". If any of these are directories, then the file .ntprc\nis searched for within those directories.\n\n### USAGE\n\n### ENVIRONMENT\n\nSee OPTION PRESETS for configuration environment variables.\n\n### FILES\n\nSee OPTION PRESETS for configuration files.\n\n### EXIT STATUS\n\nOne of the following exit values will be returned:\n\n0 (EXITSUCCESS)\nSuccessful program execution.\n\n1 (EXITFAILURE)\nThe operation failed or the command syntax was not valid.\n\n66 (EXNOINPUT)\nA specified configuration file could not be loaded.\n\n70 (EXSOFTWARE)\nlibopts had an internal operational error. Please report it to auto‐\ngen-users@lists.sourceforge.net. Thank you.\n\n### AUTHORS\n\nThe University of Delaware and Network Time Foundation\n\n### COPYRIGHT\n\nCopyright (C) 1992-2020 The University of Delaware and Network Time Foundation all rights re‐\nserved. This program is released under the terms of the NTP license, .\n\n### BUGS\n\nIt can take quite a while to generate some cryptographic values.\n\nPlease report bugs to http://bugs.ntp.org .\n\nPlease send bug reports to: http://bugs.ntp.org, bugs@ntp.org\n\n### NOTES\n\nPortions of this document came from FreeBSD.\n\nThis manual page was AutoGen-erated from the ntp-keygen option definitions.\n\nBSD June 23 2020 BSD\n\n" } ], "structuredContent": { "command": "ntp-keygen", "section": "8", "mode": "man", "summary": "ntp-keygen — Create a NTP host key", "synopsis": "ntp-keygen [-flags] [-flag [value]] [--option-name[[=| ]value]]\nAll arguments must be options.", "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [ { "flag": "-b", "long": "--imbits", "arg": null, "description": "identity modulus bits. This option takes an integer number as its argument. The value of imbits is constrained to being: in the range 256 through 2048 The number of bits in the identity modulus. The default is 256." }, { "flag": "-c", "long": "--certificate", "arg": null, "description": "certificate scheme. scheme is one of RSA-MD2, RSA-MD5, RSA-MDC2, RSA-SHA, RSA-SHA1, RSA-RIPEMD160, DSA-SHA, or DSA-SHA1. Select the certificate signature encryption/message digest scheme. Note that RSA schemes must be used with a RSA sign key and DSA schemes must be used with a DSA sign key. The default without this option is RSA-MD5." }, { "flag": "-C", "long": "--cipher", "arg": null, "description": "privatekey cipher. Select the cipher which is used to encrypt the files containing private keys. The de‐ fault is three-key triple DES in CBC mode, equivalent to \"-C des-ede3-cbc\". The openssl tool lists ciphers available in \"openssl -h\" output." }, { "flag": "-d", "long": "--debug-level", "arg": null, "description": "Increase debug verbosity level. This option may appear an unlimited number of times." }, { "flag": "-D", "long": "--set-debug-level", "arg": null, "description": "Set the debug verbosity level. This option may appear an unlimited number of times. This option takes an integer number as its argument." }, { "flag": "-e", "long": "--id-key", "arg": null, "description": "Write IFF or GQ identity keys. Write the public parameters from the IFF or GQ client keys to the standard output. This is intended for automatic key distribution by email." }, { "flag": "-G", "long": "--gq-params", "arg": null, "description": "Generate GQ parameters and keys. Generate parameters and keys for the GQ identification scheme, obsoleting any that may exist." }, { "flag": "-H", "long": "--host-key", "arg": null, "description": "generate RSA host key. Generate new host keys, obsoleting any that may exist." }, { "flag": "-I", "long": "--iffkey", "arg": null, "description": "generate IFF parameters. Generate parameters for the IFF identification scheme, obsoleting any that may exist." }, { "flag": "-i", "long": "--ident", "arg": null, "description": "set Autokey group name. Set the optional Autokey group name to name. This is used in the file name of IFF, GQ, and MV client parameters files. In that role, the default is the host name if this op‐ tion is not provided. The group name, if specified using -i/--ident or using -s/--sub‐‐ ject-name following an '@' character, is also a part of the self-signed host certifi‐ cate subject and issuer names in the form host@group and should match the ´crypto ident' or 'server ident' configuration in the ntpd configuration file." }, { "flag": "-l", "long": "--lifetime", "arg": null, "description": "set certificate lifetime. This option takes an integer number as its argument. Set the certificate expiration to lifetime days from now." }, { "flag": "-m", "long": "--modulus", "arg": null, "description": "prime modulus. This option takes an integer number as its argument. The value of modulus is constrained to being: in the range 256 through 2048 The number of bits in the prime modulus. The default is 512." }, { "flag": "-M", "long": "--md5key", "arg": null, "description": "generate symmetric keys. Generate symmetric keys, obsoleting any that may exist." }, { "flag": "-P", "long": "--pvt-cert", "arg": null, "description": "generate PC private certificate. Generate a private certificate. By default, the program generates public certificates." }, { "flag": "-p", "long": "--password", "arg": null, "description": "local private password. Local files containing private data are encrypted with the DES-CBC algorithm and the specified password. The same password must be specified to the local ntpd via the \"crypto pw password\" configuration command. The default password is the local host‐ name." }, { "flag": "-q", "long": "--export-passwd", "arg": null, "description": "export IFF or GQ group keys with password. Export IFF or GQ identity group keys to the standard output, encrypted with the DES-CBC algorithm and the specified password. The same password must be specified to the re‐ mote ntpd via the \"crypto pw password\" configuration command. See also the option --id-key (-e) for unencrypted exports." }, { "flag": "-s", "long": "--subject-name", "arg": null, "description": "set host and optionally group name. Set the Autokey host name, and optionally, group name specified following an '@' char‐ acter. The host name is used in the file name of generated host and signing certifi‐ cates, without the group name. The host name, and if provided, group name are used in host@group form for the host certificate subject and issuer fields. Specifying '-s @group' is allowed, and results in leaving the host name unchanged while appending @group to the subject and issuer fields, as with -i group. The group name, or if not provided, the host name are also used in the file names of IFF, GQ, and MV client pa‐ rameter files." }, { "flag": "-S", "long": "--sign-key", "arg": null, "description": "generate sign key (RSA or DSA). Generate a new sign key of the designated type, obsoleting any that may exist. By de‐ fault, the program uses the host key as the sign key." }, { "flag": "-T", "long": "--trusted-cert", "arg": null, "description": "trusted certificate (TC scheme). Generate a trusted certificate. By default, the program generates a non-trusted cer‐ tificate." }, { "flag": "-V", "long": "--mv-params", "arg": null, "description": "generate MV parameters. This option takes an integer number as its argument. Generate parameters and keys for the Mu-Varadharajan (MV) identification scheme." }, { "flag": "-v", "long": "--mv-keys", "arg": null, "description": "update MV keys. This option takes an integer number as its argument. This option has not been fully documented. -?, --help Display usage information and exit. -!, --more-help Pass the extended usage information through a pager. -> [cfgfile], --save-opts [=cfgfile] Save the option state to cfgfile. The default is the last configuration file listed in the OPTION PRESETS section, below. The command will exit after updating the config file. -< cfgfile, --load-opts=cfgfile, --no-load-opts Load options from cfgfile. The no-load-opts form will disable the loading of earlier config/rc/ini files. --no-load-opts is handled early, out of order. --version [{v|c|n}] Output version of program and exit. The default mode is `v', a simple version. The `c' mode will print copyright information and `n' will print the full copyright notice." } ], "examples": [], "see_also": [], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 4, "subsections": [] }, { "name": "DESCRIPTION", "lines": 55, "subsections": [ { "name": "Running the Program", "lines": 101 }, { "name": "Trusted Hosts and Groups", "lines": 32 }, { "name": "Identity Schemes", "lines": 63 }, { "name": "Command Line Options", "lines": 1 }, { "name": "-b --imbits", "lines": 6, "flag": "-b", "long": "--imbits" }, { "name": "-c --certificate", "lines": 7, "flag": "-c", "long": "--certificate" }, { "name": "-C --cipher", "lines": 4, "flag": "-C", "long": "--cipher" }, { "name": "-d --debug-level", "lines": 3, "flag": "-d", "long": "--debug-level" }, { "name": "-D --set-debug-level", "lines": 3, "flag": "-D", "long": "--set-debug-level" }, { "name": "-e --id-key", "lines": 4, "flag": "-e", "long": "--id-key" }, { "name": "-G --gq-params", "lines": 3, "flag": "-G", "long": "--gq-params" }, { "name": "-H --host-key", "lines": 2, "flag": "-H", "long": "--host-key" }, { "name": "-I --iffkey", "lines": 3, "flag": "-I", "long": "--iffkey" }, { "name": "-i --ident", "lines": 7, "flag": "-i", "long": "--ident" }, { "name": "-l --lifetime", "lines": 3, "flag": "-l", "long": "--lifetime" }, { "name": "-m --modulus", "lines": 5, "flag": "-m", "long": "--modulus" }, { "name": "-M --md5key", "lines": 6, "flag": "-M", "long": "--md5key" }, { "name": "-p --password", "lines": 4, "flag": "-p", "long": "--password" }, { "name": "-P --pvt-cert", "lines": 4, "flag": "-P", "long": "--pvt-cert" }, { "name": "-q --export-passwd", "lines": 5, "flag": "-q", "long": "--export-passwd" }, { "name": "-s --subject-key", "lines": 8, "flag": "-s", "long": "--subject-key" }, { "name": "-S --sign-key", "lines": 4, "flag": "-S", "long": "--sign-key" }, { "name": "-T --trusted-cert", "lines": 3, "flag": "-T", "long": "--trusted-cert" }, { "name": "-V --mv-params", "lines": 4, "flag": "-V", "long": "--mv-params" }, { "name": "Random Seed File", "lines": 24 }, { "name": "Cryptographic Data Files", "lines": 66 } ] }, { "name": "OPTIONS", "lines": 1, "subsections": [ { "name": "-b --imbits", "lines": 6, "flag": "-b", "long": "--imbits" }, { "name": "-c --certificate", "lines": 9, "flag": "-c", "long": "--certificate" }, { "name": "-C --cipher", "lines": 6, "flag": "-C", "long": "--cipher" }, { "name": "-d --debug-level", "lines": 3, "flag": "-d", "long": "--debug-level" }, { "name": "-D --set-debug-level", "lines": 4, "flag": "-D", "long": "--set-debug-level" }, { "name": "-e --id-key", "lines": 5, "flag": "-e", "long": "--id-key" }, { "name": "-G --gq-params", "lines": 5, "flag": "-G", "long": "--gq-params" }, { "name": "-H --host-key", "lines": 4, "flag": "-H", "long": "--host-key" }, { "name": "-I --iffkey", "lines": 4, "flag": "-I", "long": "--iffkey" }, { "name": "-i --ident", "lines": 9, "flag": "-i", "long": "--ident" }, { "name": "-l --lifetime", "lines": 4, "flag": "-l", "long": "--lifetime" }, { "name": "-m --modulus", "lines": 6, "flag": "-m", "long": "--modulus" }, { "name": "-M --md5key", "lines": 4, "flag": "-M", "long": "--md5key" }, { "name": "-P --pvt-cert", "lines": 4, "flag": "-P", "long": "--pvt-cert" }, { "name": "-p --password", "lines": 7, "flag": "-p", "long": "--password" }, { "name": "-q --export-passwd", "lines": 7, "flag": "-q", "long": "--export-passwd" }, { "name": "-s --subject-name", "lines": 11, "flag": "-s", "long": "--subject-name" }, { "name": "-S --sign-key", "lines": 5, "flag": "-S", "long": "--sign-key" }, { "name": "-T --trusted-cert", "lines": 5, "flag": "-T", "long": "--trusted-cert" }, { "name": "-V --mv-params", "lines": 4, "flag": "-V", "long": "--mv-params" }, { "name": "-v --mv-keys", "lines": 23, "flag": "-v", "long": "--mv-keys" } ] }, { "name": "OPTION PRESETS", "lines": 7, "subsections": [] }, { "name": "USAGE", "lines": 1, "subsections": [] }, { "name": "ENVIRONMENT", "lines": 2, "subsections": [] }, { "name": "FILES", "lines": 2, "subsections": [] }, { "name": "EXIT STATUS", "lines": 15, "subsections": [] }, { "name": "AUTHORS", "lines": 2, "subsections": [] }, { "name": "COPYRIGHT", "lines": 3, "subsections": [] }, { "name": "BUGS", "lines": 6, "subsections": [] }, { "name": "NOTES", "lines": 5, "subsections": [] } ] } }