Updated: 2021/Apr/14


NTP_KEYGEN(8)           System Manager's Manual (user)           NTP_KEYGEN(8)

NAME
     ntp-keygen - Create a NTP host key

SYNOPSIS
     ntp-keygen [-flags] [-flag [value]] [--option-name[[=| ]value]]

                All arguments must be options.

DESCRIPTION
     This program generates cryptographic data files used by the NTPv4
     authentication and identification schemes.  It can generate message
     digest keys used in symmetric key cryptography and, if the OpenSSL
     software library has been installed, it can generate host keys, signing
     keys, certificates, and identity keys and parameters used in Autokey
     public key cryptography.  These files are used for cookie encryption,
     digital signature, and challenge/response identification algorithms
     compatible with the Internet standard security infrastructure.

     The message digest symmetric keys file is generated in a format
     compatible with NTPv3.  All other files are in PEM-encoded printable
     ASCII format, so they can be embedded as MIME attachments in email to
     other sites and certificate authorities.  By default, files are not
     encrypted.

     When used to generate message digest symmetric keys, the program produces
     a file containing ten pseudo-random printable ASCII strings suitable for
     the MD5 message digest algorithm included in the distribution.  If the
     OpenSSL library is installed, it produces an additional ten hex-encoded
     random bit strings suitable for SHA1, AES-128-CMAC, and other message
     digest algorithms.  The message digest symmetric keys file must be
     distributed and stored using secure means beyond the scope of NTP itself.
     Besides the keys used for ordinary NTP associations, additional keys can
     be defined as passwords for the ntpq(1ntpqmdoc) and ntpdc(1ntpdcmdoc)
     utility programs.

     The remaining generated files are compatible with other OpenSSL
     applications and other Public Key Infrastructure (PKI) resources.
     Certificates generated by this program are compatible with extant
     industry practice, although some users might find the interpretation of
     X509v3 extension fields somewhat liberal.  However, the identity keys are
     probably not compatible with anything other than Autokey.

     Some files used by this program are encrypted using a private password.
     The -p option specifies the read password for local encrypted files and
     the -q option the write password for encrypted files sent to remote
     sites.  If no password is specified, the host name returned by the Unix
     hostname(1) command, normally the DNS name of the host, is used as the
     the default read password, for convenience.  The ntp-keygen program
     prompts for the password if it reads an encrypted file and the password
     is missing or incorrect.  If an encrypted file is read successfully and
     no write password is specified, the read password is used as the write
     password by default.

     The pw option of the crypto ntpd(1ntpdmdoc) configuration command
     specifies the read password for previously encrypted local files.  This
     must match the local read password used by this program.  If not
     specified, the host name is used.  Thus, if files are generated by this
     program without an explicit password, they can be read back by
     ntpd(1ntpdmdoc) without specifying an explicit password but only on the
     same host.  If the write password used for encryption is specified as the
     host name, these files can be read by that host with no explicit
     password.

     Normally, encrypted files for each host are generated by that host and
     used only by that host, although exceptions exist as noted later on this
     page.  The symmetric keys file, normally called ntp.keys, is usually
     installed in /etc.  Other files and links are usually installed in
     /usr/local/etc, which is normally in a shared filesystem in NFS-mounted
     networks and cannot be changed by shared clients.  In these cases, NFS
     clients can specify the files in another directory such as /etc using the
     keysdir ntpd(1ntpdmdoc) configuration file command.

     This program directs commentary and error messages to the standard error
     stream stderr and remote files to the standard output stream stdout where
     they can be piped to other applications or redirected to files.  The
     names used for generated files and links all begin with the string
     ntpkey* and include the file type, generating host and filestamp, as
     described in the Cryptographic Data Files section below.

   Running the Program
     The safest way to run the ntp-keygen program is logged in directly as
     root.  The recommended procedure is change to the keys directory, usually
     /usr/local/etc, then run the program.

     To test and gain experience with Autokey concepts, log in as root and
     change to the keys directory, usually /usr/local/etc.  When run for the
     first time, or if all files with names beginning with ntpkey* have been
     removed, use the ntp-keygen command without arguments to generate a
     default RSA host key and matching RSA-MD5 certificate file with
     expiration date one year hence, which is all that is necessary in many
     cases.  The program also generates soft links from the generic names to
     the respective files.  If run again without options, the program uses the
     existing keys and parameters and generates a new certificate file with
     new expiration date one year hence, and soft link.

     The host key is used to encrypt the cookie when required and so must be
     RSA type.  By default, the host key is also the sign key used to encrypt
     signatures.  When necessary, a different sign key can be specified and
     this can be either RSA or DSA type.  By default, the message digest type
     is MD5, but any combination of sign key type and message digest type
     supported by the OpenSSL library can be specified, including those using
     the AES128CMAC, MD2, MD5, MDC2, SHA, SHA1 and RIPE160 message digest
     algorithms.  However, the scheme specified in the certificate must be
     compatible with the sign key.  Certificates using any digest algorithm
     are compatible with RSA sign keys; however, only SHA and SHA1
     certificates are compatible with DSA sign keys.

     Private/public key files and certificates are compatible with other
     OpenSSL applications and very likely other libraries as well.
     Certificates or certificate requests derived from them should be
     compatible with extant industry practice, although some users might find
     the interpretation of X509v3 extension fields somewhat liberal.  However,
     the identification parameter files, although encoded as the other files,
     are probably not compatible with anything other than Autokey.

     Running the program as other than root and using the Unix su(1) command
     to assume root may not work properly, since by default the OpenSSL
     library looks for the random seed file .rnd in the user home directory.
     However, there should be only one .rnd, most conveniently in the root
     directory, so it is convenient to define the RANDFILE environment
     variable used by the OpenSSL library as the path to .rnd.

     Installing the keys as root might not work in NFS-mounted shared file
     systems, as NFS clients may not be able to write to the shared keys
     directory, even as root.  In this case, NFS clients can specify the files
     in another directory such as /etc using the keysdir ntpd(1ntpdmdoc)
     configuration file command.  There is no need for one client to read the
     keys and certificates of other clients or servers, as these data are
     obtained automatically by the Autokey protocol.

     Ordinarily, cryptographic files are generated by the host that uses them,
     but it is possible for a trusted agent (TA) to generate these files for
     other hosts; however, in such cases files should always be encrypted.
     The subject name and trusted name default to the hostname of the host
     generating the files, but can be changed by command line options.  It is
     convenient to designate the owner name and trusted name as the subject
     and issuer fields, respectively, of the certificate.  The owner name is
     also used for the host and sign key files, while the trusted name is used
     for the identity files.

     All files are installed by default in the keys directory /usr/local/etc,
     which is normally in a shared filesystem in NFS-mounted networks.  The
     actual location of the keys directory and each file can be overridden by
     configuration commands, but this is not recommended.  Normally, the files
     for each host are generated by that host and used only by that host,
     although exceptions exist as noted later on this page.

     Normally, files containing private values, including the host key, sign
     key and identification parameters, are permitted root read/write-only;
     while others containing public values are permitted world readable.
     Alternatively, files containing private values can be encrypted and these
     files permitted world readable, which simplifies maintenance in shared
     file systems.  Since uniqueness is insured by the hostname and filestamp
     file name extensions, the files for an NTP server and dependent clients
     can all be installed in the same shared directory.

     The recommended practice is to keep the file name extensions when
     installing a file and to install a soft link from the generic names
     specified elsewhere on this page to the generated files.  This allows new
     file generations to be activated simply by changing the link.  If a link
     is present, ntpd(1ntpdmdoc) follows it to the file name to extract the
     filestamp.  If a link is not present, ntpd(1ntpdmdoc) extracts the
     filestamp from the file itself.  This allows clients to verify that the
     file and generation times are always current.  The ntp-keygen program
     uses the same filestamp extension for all files generated at one time, so
     each generation is distinct and can be readily recognized in monitoring
     data.

     Run the command on as many hosts as necessary.  Designate one of them as
     the trusted host (TH) using ntp-keygen with the -T option and configure
     it to synchronize from reliable Internet servers.  Then configure the
     other hosts to synchronize to the TH directly or indirectly.  A
     certificate trail is created when Autokey asks the immediately ascendant
     host towards the TH to sign its certificate, which is then provided to
     the immediately descendant host on request.  All group hosts should have
     acyclic certificate trails ending on the TH.

     The host key is used to encrypt the cookie when required and so must be
     RSA type.  By default, the host key is also the sign key used to encrypt
     signatures.  A different sign key can be assigned using the -S option and
     this can be either RSA or DSA type.  By default, the signature message
     digest type is MD5, but any combination of sign key type and message
     digest type supported by the OpenSSL library can be specified using the
     -c option.

     The rules say cryptographic media should be generated with proventic
     filestamps, which means the host should already be synchronized before
     this program is run.  This of course creates a chicken-and-egg problem
     when the host is started for the first time.  Accordingly, the host time
     should be set by some other means, such as eyeball-and-wristwatch, at
     least so that the certificate lifetime is within the current year.  After
     that and when the host is synchronized to a proventic source, the
     certificate should be re-generated.

     Additional information on trusted groups and identity schemes is on the
     "Autokey Public-Key Authentication" page.

     File names begin with the prefix ntpkey_ and end with the suffix
     _hostname. filestamp, where hostname is the owner name, usually the
     string returned by the Unix hostname(1) command, and filestamp is the NTP
     seconds when the file was generated, in decimal digits.  This both
     guarantees uniqueness and simplifies maintenance procedures, since all
     files can be quickly removed by a rm ntpkey* command or all files
     generated at a specific time can be removed by a rm *filestamp command.
     To further reduce the risk of misconfiguration, the first two lines of a
     file contain the file name and generation date and time as comments.

   Trusted Hosts and Groups
     Each cryptographic configuration involves selection of a signature scheme
     and identification scheme, called a cryptotype, as explained in the
     Authentication Options section of ntp.conf(5).  The default cryptotype
     uses RSA encryption, MD5 message digest and TC identification.  First,
     configure a NTP subnet including one or more low-stratum trusted hosts
     from which all other hosts derive synchronization directly or indirectly.
     Trusted hosts have trusted certificates; all other hosts have nontrusted
     certificates.  These hosts will automatically and dynamically build
     authoritative certificate trails to one or more trusted hosts.  A trusted
     group is the set of all hosts that have, directly or indirectly, a
     certificate trail ending at a trusted host.  The trail is defined by
     static configuration file entries or dynamic means described on the
     Automatic NTP Configuration Options section of ntp.conf(5).

     On each trusted host as root, change to the keys directory.  To insure a
     fresh fileset, remove all ntpkey files.  Then run ntp-keygen -T to
     generate keys and a trusted certificate.  On all other hosts do the same,
     but leave off the -T flag to generate keys and nontrusted certificates.
     When complete, start the NTP daemons beginning at the lowest stratum and
     working up the tree.  It may take some time for Autokey to instantiate
     the certificate trails throughout the subnet, but setting up the
     environment is completely automatic.

     If it is necessary to use a different sign key or different
     digest/signature scheme than the default, run ntp-keygen with the -S type
     option, where type is either RSA or DSA.  The most frequent need to do
     this is when a DSA-signed certificate is used.  If it is necessary to use
     a different certificate scheme than the default, run ntp-keygen with the
     -c scheme option and selected scheme as needed.  If ntp-keygen is run
     again without these options, it generates a new certificate using the
     same scheme and sign key, and soft link.

     After setting up the environment it is advisable to update certificates
     from time to time, if only to extend the validity interval.  Simply run
     ntp-keygen with the same flags as before to generate new certificates
     using existing keys, and soft links.  However, if the host or sign key is
     changed, ntpd(1ntpdmdoc) should be restarted.  When ntpd(1ntpdmdoc) is
     restarted, it loads any new files and restarts the protocol.  Other
     dependent hosts will continue as usual until signatures are refreshed, at
     which time the protocol is restarted.

   Identity Schemes
     As mentioned on the Autonomous Authentication page, the default TC
     identity scheme is vulnerable to a middleman attack.  However, there are
     more secure identity schemes available, including PC, IFF, GQ and MV
     schemes described below.  These schemes are based on a TA, one or more
     trusted hosts and some number of nontrusted hosts.  Trusted hosts prove
     identity using values provided by the TA, while the remaining hosts prove
     identity using values provided by a trusted host and certificate trails
     that end on that host.  The name of a trusted host is also the name of
     its sugroup and also the subject and issuer name on its trusted
     certificate.  The TA is not necessarily a trusted host in this sense, but
     often is.

     In some schemes there are separate keys for servers and clients.  A
     server can also be a client of another server, but a client can never be
     a server for another client.  In general, trusted hosts and nontrusted
     hosts that operate as both server and client have parameter files that
     contain both server and client keys.  Hosts that operate only as clients
     have key files that contain only client keys.

     The PC scheme supports only one trusted host in the group.  On trusted
     host alice run ntp-keygen -P -p password to generate the host key file
     ntpkey_ RSA key_alice. filestamp and trusted private certificate file
     ntpkey_ RSA-MD5 _ cert_alice. filestamp, and soft links.  Copy both files
     to all group hosts; they replace the files which would be generated in
     other schemes.  On each host bob install a soft link from the generic
     name ntpkey_host_bob to the host key file and soft link ntpkey_cert_bob
     to the private certificate file.  Note the generic links are on bob, but
     point to files generated by trusted host alice.  In this scheme it is not
     possible to refresh either the keys or certificates without copying them
     to all other hosts in the group, and recreating the soft links.

     For the IFF scheme proceed as in the TC scheme to generate keys and
     certificates for all group hosts, then for every trusted host in the
     group, generate the IFF parameter file.  On trusted host alice run
     ntp-keygen -T -I -p password to produce her parameter file
     ntpkey_IFFpar_alice.filestamp, which includes both server and client
     keys.  Copy this file to all group hosts that operate as both servers and
     clients and install a soft link from the generic ntpkey_iff_alice to this
     file.  If there are no hosts restricted to operate only as clients, there
     is nothing further to do.  As the IFF scheme is independent of keys and
     certificates, these files can be refreshed as needed.

     If a rogue client has the parameter file, it could masquerade as a
     legitimate server and present a middleman threat.  To eliminate this
     threat, the client keys can be extracted from the parameter file and
     distributed to all restricted clients.  After generating the parameter
     file, on alice run ntp-keygen -e and pipe the output to a file or email
     program.  Copy or email this file to all restricted clients.  On these
     clients install a soft link from the generic ntpkey_iff_alice to this
     file.  To further protect the integrity of the keys, each file can be
     encrypted with a secret password.

     For the GQ scheme proceed as in the TC scheme to generate keys and
     certificates for all group hosts, then for every trusted host in the
     group, generate the IFF parameter file.  On trusted host alice run
     ntp-keygen -T -G -p password to produce her parameter file
     ntpkey_GQpar_alice.filestamp, which includes both server and client keys.
     Copy this file to all group hosts and install a soft link from the
     generic ntpkey_gq_alice to this file.  In addition, on each host bob
     install a soft link from generic ntpkey_gq_bob to this file.  As the GQ
     scheme updates the GQ parameters file and certificate at the same time,
     keys and certificates can be regenerated as needed.

     For the MV scheme, proceed as in the TC scheme to generate keys and
     certificates for all group hosts.  For illustration assume trish is the
     TA, alice one of several trusted hosts and bob one of her clients.  On TA
     trish run ntp-keygen -V n -p password, where n is the number of revokable
     keys (typically 5) to produce the parameter file
     ntpkeys_MVpar_trish.filestamp and client key files ntpkeys_MVkeyd _
     trish. filestamp where d is the key number (0 < d < n).  Copy the
     parameter file to alice and install a soft link from the generic
     ntpkey_mv_alice to this file.  Copy one of the client key files to alice
     for later distribution to her clients.  It does not matter which client
     key file goes to alice, since they all work the same way.  Alice copies
     the client key file to all of her clients.  On client bob install a soft
     link from generic ntpkey_mvkey_bob to the client key file.  As the MV
     scheme is independent of keys and certificates, these files can be
     refreshed as needed.

   Command Line Options
     -b --imbits= modulus
             Set the number of bits in the identity modulus for generating
             identity keys to modulus bits.  The number of bits in the
             identity modulus defaults to 256, but can be set to values from
             256 to 2048 (32 to 256 octets).  Use the larger moduli with
             caution, as this can consume considerable computing resources and
             increases the size of authenticated packets.

     -c --certificate= scheme
             Select certificate signature encryption/message digest scheme.
             The scheme can be one of the following: RSA-MD2, RSA-MD5,
             RSA-MDC2, RSA-SHA, RSA-SHA1, RSA-RIPEMD160, DSA-SHA, or DSA-SHA1.
             Note that RSA schemes must be used with an RSA sign key and DSA
             schemes must be used with a DSA sign key.  The default without
             this option is RSA-MD5.  If compatibility with FIPS 140-2 is
             required, either the DSA-SHA or DSA-SHA1 scheme must be used.

     -C --cipher= cipher
             Select the OpenSSL cipher to encrypt the files containing private
             keys.  The default without this option is three-key triple DES in
             CBC mode, des-ede3-cbc.  The openssl -h command provided with
             OpenSSL displays available ciphers.

     -d --debug-level
             Increase debugging verbosity level.  This option displays the
             cryptographic data produced in eye-friendly billboards.

     -D --set-debug-level= level
             Set the debugging verbosity to level.  This option displays the
             cryptographic data produced in eye-friendly billboards.

     -e --id-key
             Write the IFF or GQ public parameters from the IFFkey or GQkey
             client keys file previously specified as unencrypted data to the
             standard output stream stdout.  This is intended for automatic
             key distribution by email.

     -G --gq-params
             Generate a new encrypted GQ parameters and key file for the
             Guillou-Quisquater (GQ) identity scheme.  This option is mutually
             exclusive with the -I and -V options.

     -H --host-key
             Generate a new encrypted RSA public/private host key file.

     -I --iffkey
             Generate a new encrypted IFF key file for the Schnorr (IFF)
             identity scheme.  This option is mutually exclusive with the -G
             and Fl V options.

     -i --ident= group
             Set the optional Autokey group name to group.  This is used in
             the identity scheme parameter file names of IFF, GQ, and MV
             client parameters files.  In that role, the default is the host
             name if no group is provided.  The group name, if specified using
             -i or -s following an `@' character, is also used in certificate
             subject and issuer names in the form host @ group and should
             match the group specified via crypto ident or server ident in the
             ntpd configuration file.

     -l --lifetime= days
             Set the lifetime for certificate expiration to days.  The default
             lifetime is one year (365 days).

     -m --modulus= bits
             Set the number of bits in the prime modulus for generating files
             to bits.  The modulus defaults to 512, but can be set from 256 to
             2048 (32 to 256 octets).  Use the larger moduli with caution, as
             this can consume considerable computing resources and increases
             the size of authenticated packets.

     -M --md5key
             Generate a new symmetric keys file containing 10 MD5 keys, and if
             OpenSSL is available, 10 SHA keys.  An MD5 key is a string of 20
             random printable ASCII characters, while a SHA key is a string of
             40 random hex digits.  The file can be edited using a text editor
             to change the key type or key content.  This option is mutually
             exclusive with all other options.

     -p --password= passwd
             Set the password for reading and writing encrypted files to
             passwd.  These include the host, sign and identify key files.  By
             default, the password is the string returned by the Unix hostname
             command.

     -P --pvt-cert
             Generate a new private certificate used by the PC identity
             scheme.  By default, the program generates public certificates.
             Note: the PC identity scheme is not recommended for new
             installations.

     -q --export-passwd= passwd
             Set the password for writing encrypted IFF, GQ and MV identity
             files redirected to stdout to passwd.  In effect, these files are
             decrypted with the -p password, then encrypted with the -q
             password.  By default, the password is the string returned by the
             Unix hostname command.

     -s --subject-key= file ... [host] [@ group]
             Specify the Autokey host name, where host is the optional host
             name and group is the optional group name.  The host name, and if
             provided, group name are used in host @ group form as certificate
             subject and issuer.  Specifying -s -@ group is allowed, and
             results in leaving the host name unchanged, as with -i group.
             The group name, or if no group is provided, the host name are
             also used in the file names of IFF, GQ, and MV identity scheme
             client parameter files.  If host is not specified, the default
             host name is the string returned by the Unix hostname command.

     -S --sign-key= [RSA | DSA]
             Generate a new encrypted public/private sign key file of the
             specified type.  By default, the sign key is the host key and has
             the same type.  If compatibility with FIPS 140-2 is required, the
             sign key type must be DSA.

     -T --trusted-cert
             Generate a trusted certificate.  By default, the program
             generates a non-trusted certificate.

     -V --mv-params nkeys
             Generate nkeys encrypted server keys and parameters for the
             Mu-Varadharajan (MV) identity scheme.  This option is mutually
             exclusive with the -I and -G options.  Note: support for this
             option should be considered a work in progress.

   Random Seed File
     All cryptographically sound key generation schemes must have means to
     randomize the entropy seed used to initialize the internal pseudo-random
     number generator used by the library routines.  The OpenSSL library uses
     a designated random seed file for this purpose.  The file must be
     available when starting the NTP daemon and ntp-keygen program.  If a site
     supports OpenSSL or its companion OpenSSH, it is very likely that means
     to do this are already available.

     It is important to understand that entropy must be evolved for each
     generation, for otherwise the random number sequence would be
     predictable.  Various means dependent on external events, such as
     keystroke intervals, can be used to do this and some systems have
     built-in entropy sources.  Suitable means are described in the OpenSSL
     software documentation, but are outside the scope of this page.

     The entropy seed used by the OpenSSL library is contained in a file,
     usually called .rnd, which must be available when starting the NTP daemon
     or the ntp-keygen program.  The NTP daemon will first look for the file
     using the path specified by the randfile subcommand of the crypto
     configuration command.  If not specified in this way, or when starting
     the ntp-keygen program, the OpenSSL library will look for the file using
     the path specified by the RANDFILE environment variable in the user home
     directory, whether root or some other user.  If the RANDFILE environment
     variable is not present, the library will look for the .rnd file in the
     user home directory.  Since both the ntp-keygen program and
     ntpd(1ntpdmdoc) daemon must run as root, the logical place to put this
     file is in /.rnd or /root/.rnd.  If the file is not available or cannot
     be written, the daemon exits with a message to the system log and the
     program exits with a suitable error message.

   Cryptographic Data Files
     All file formats begin with two nonencrypted lines.  The first line
     contains the file name, including the generated host name and filestamp,
     in the format ntpkey_key _ name. filestamp, where key is the key or
     parameter type, name is the host or group name and filestamp is the
     filestamp (NTP seconds) when the file was created.  By convention, key
     names in generated file names include both upper and lower case
     characters, while key names in generated link names include only lower
     case characters.  The filestamp is not used in generated link names.  The
     second line contains the datestamp in conventional Unix date format.
     Lines beginning with `#' are considered comments and ignored by the
     ntp-keygen program and ntpd(1ntpdmdoc) daemon.

     The remainder of the file contains cryptographic data, encoded first
     using ASN.1 rules, then encrypted if necessary, and finally written in
     PEM-encoded printable ASCII text, preceded and followed by MIME content
     identifier lines.

     The format of the symmetric keys file, ordinarily named ntp.keys, is
     somewhat different than the other files in the interest of backward
     compatibility.  Ordinarily, the file is generated by this program, but it
     can be constructed and edited using an ordinary text editor.

           # ntpkey_MD5key_bk.ntp.org.3595864945
           # Thu Dec 12 19:22:25 2013
           1  MD5 L";Nw<`.I<f4U0)247"i  # MD5 key
           2  MD5 &>l0%XXK9O'51VwV<xq~  # MD5 key
           3  MD5 lb4zLW~d^!K:]RsD'qb6  # MD5 key
           4  MD5 Yue:tL[+vR)M`n~bY,'?  # MD5 key
           5  MD5 B;fx'Kgr/&4ZTbL6=RxA  # MD5 key
           6  MD5 4eYwa`o}3i@@V@..R9!l  # MD5 key
           7  MD5 `A.([h+;wTQ|xfi%Sn_!  # MD5 key
           8  MD5 45:V,r4]l6y^JH6"Sh?F  # MD5 key
           9  MD5 3-5vcn*6l29DS?Xdsg)*  # MD5 key
           10 MD5 2late4Me              # MD5 key
           11 SHA1 a27872d3030a9025b8446c751b4551a7629af65c  # SHA1 key
           12 SHA1 21bc3b4865dbb9e920902abdccb3e04ff97a5e74  # SHA1 key
           13 SHA1 2b7736fe24fef5ba85ae11594132ab5d6f6daba9  # SHA1 key
           14 SHA  a5332809c8878dd3a5b918819108a111509aeceb  # SHA  key
           15 MD2  2fe16c88c760ff2f16d4267e36c1aa6c926e6964  # MD2  key
           16 MD4  b2691811dc19cfc0e2f9bcacd74213f29812183d  # MD4  key
           17 MD5  e4d6735b8bdad58ec5ffcb087300a17f7fef1f7c  # MD5  key
           18 MDC2 a8d5e2315c025bf3a79174c87fbd10477de2eabc  # MDC2 key
           19 RIPEMD160 77ca332cafb30e3cafb174dcd5b80ded7ba9b3d2  # RIPEMD160 key
           20 AES128CMAC f92ff73eee86c1e7dc638d6489a04e4e555af878  # AES128CMAC key
           Figure 1. Typical Symmetric Key File

     Figure 1 shows a typical symmetric keys file used by the reference
     implementation.  Following the header the keys are entered one per line
     in the format
           keyno type key
     where keyno is a positive integer in the range 1-65535; type is the key
     type for the message digest algorithm, which in the absence of the
     OpenSSL library must be MD5 to designate the MD5 message digest
     algorithm; if the OpenSSL library is installed, the key type can be any
     message digest algorithm supported by that library; however, if
     compatibility with FIPS 140-2 is required, the key type must be either
     SHA or SHA1; key is the key itself, which is a printable ASCII string 20
     characters or less in length: each character is chosen from the 93
     printable characters in the range 0x21 through 0x7e ( `'!  through `~' )
     excluding space and the `#' character, and terminated by whitespace or a
     `#' character.  An OpenSSL key consists of a hex-encoded ASCII string of
     40 characters, which is truncated as necessary.

     Note that the keys used by the ntpq(1ntpqmdoc) and ntpdc(1ntpdcmdoc)
     programs are checked against passwords requested by the programs and
     entered by hand, so it is generally appropriate to specify these keys in
     human readable ASCII format.

     The ntp-keygen program generates a symmetric keys file
     ntpkey_MD5key_hostname.filestamp.  Since the file contains private shared
     keys, it should be visible only to root and distributed by secure means
     to other subnet hosts.  The NTP daemon loads the file ntp.keys, so
     ntp-keygen installs a soft link from this name to the generated file.
     Subsequently, similar soft links must be installed by manual or automated
     means on the other subnet hosts.  While this file is not used with the
     Autokey Version 2 protocol, it is needed to authenticate some remote
     configuration commands used by the ntpq(1ntpqmdoc) and ntpdc(1ntpdcmdoc)
     utilities.

OPTIONS
     -b imbits, --imbits=imbits
             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.

     -c scheme, --certificate=scheme
             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.

     -C cipher, --cipher=cipher
             privatekey cipher.

             Select the cipher which is used to encrypt the files containing
             private keys.  The default is three-key triple DES in CBC mode,
             equivalent to "-C des-ede3-cbc".  The openssl tool lists ciphers
             available in "openssl -h" output.

     -d, --debug-level
             Increase debug verbosity level.  This option may appear an
             unlimited number of times.


     -D number, --set-debug-level=number
             Set the debug verbosity level.  This option may appear an
             unlimited number of times.  This option takes an integer number
             as its argument.


     -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 is intended for automatic key distribution
             by email.

     -G, --gq-params
             Generate GQ parameters and keys.

             Generate parameters and keys for the GQ identification scheme,
             obsoleting any that may exist.

     -H, --host-key
             generate RSA host key.

             Generate new host keys, obsoleting any that may exist.

     -I, --iffkey
             generate IFF parameters.

             Generate parameters for the IFF identification scheme, obsoleting
             any that may exist.

     -i group, --ident=group
             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 option is not
             provided.  The group name, if specified using -i/--ident or using
             -s/--subject-name following an '@' character, is also a part of
             the self-signed host certificate subject and issuer names in the
             form host@group and should match the 'crypto ident' or 'server
             ident' configuration in the ntpd configuration file.

     -l lifetime, --lifetime=lifetime
             set certificate lifetime.  This option takes an integer number as
             its argument.

             Set the certificate expiration to lifetime days from now.

     -m modulus, --modulus=modulus
             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.

     -M, --md5key
             generate symmetric keys.

             Generate symmetric keys, obsoleting any that may exist.

     -P, --pvt-cert
             generate PC private certificate.

             Generate a private certificate.  By default, the program
             generates public certificates.

     -p passwd, --password=passwd
             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
             hostname.

     -q passwd, --export-passwd=passwd
             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 remote ntpd via the
             "crypto pw password" configuration command.  See also the option
             --id-key (-e) for unencrypted exports.

     -s host@group, --subject-name=host@group
             set host and optionally group name.

             Set the Autokey host name, and optionally, group name specified
             following an '@' character.  The host name is used in the file
             name of generated host and signing certificates, 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 parameter files.

     -S sign, --sign-key=sign
             generate sign key (RSA or DSA).

             Generate a new sign key of the designated type, obsoleting any
             that may exist.  By default, the program uses the host key as the
             sign key.

     -T, --trusted-cert
             trusted certificate (TC scheme).

             Generate a trusted certificate.  By default, the program
             generates a non-trusted certificate.

     -V num, --mv-params=num
             generate <num> MV parameters.  This option takes an integer
             number as its argument.

             Generate parameters and keys for the Mu-Varadharajan (MV)
             identification scheme.

     -v num, --mv-keys=num
             update <num> 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.

OPTION PRESETS
     Any option that is not marked as not presettable may be preset by loading
     values from configuration ("RC" or ".INI") file(s) and values from
     environment variables named:
       NTP_KEYGEN_<option-name> or NTP_KEYGEN
     The environmental presets take precedence (are processed later than) the
     configuration files.  The homerc files are "$HOME", and ".".  If any of
     these are directories, then the file .ntprc is searched for within those
     directories.

USAGE
ENVIRONMENT
     See OPTION PRESETS for configuration environment variables.

FILES
     See OPTION PRESETS for configuration files.

EXIT STATUS
     One of the following exit values will be returned:

     0  (EXIT_SUCCESS)
             Successful program execution.

     1  (EXIT_FAILURE)
             The operation failed or the command syntax was not valid.

     66  (EX_NOINPUT)
             A specified configuration file could not be loaded.

     70  (EX_SOFTWARE)
             libopts had an internal operational error.  Please report it to
             autogen-users@lists.sourceforge.net.  Thank you.

AUTHORS
     The University of Delaware and Network Time Foundation

COPYRIGHT
     Copyright (C) 1992-2020 The University of Delaware and Network Time
     Foundation all rights reserved.  This program is released under the terms
     of the NTP license, <http://ntp.org/license>.

BUGS
     It can take quite a while to generate some cryptographic values.

     Please report bugs to http://bugs.ntp.org .

     Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org

NOTES
     Portions of this document came from FreeBSD.

     This manual page was AutoGen-erated from the ntp-keygen option
     definitions.

NetBSD 9.99                      March 3 2020                      NetBSD 9.99