Ubuntu Manpage: ntp-keygen — Create a NTP host key

Provided by: ntp_4.2.8p10+dfsg-5ubuntu7.3_amd64

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 generates MD5 key files used in symmetric key cryptography. In addition, if the OpenSSL
software library has been installed, it generates keys, certificate and identity files used in public key
cryptography. These files are used for cookie encryption, digital signature and challenge/response
identification algorithms compatible with the Internet standard security infrastructure.

All files are in PEM-encoded printable ASCII format, so they can be embedded as MIME attachments in mail
to other sites and certificate authorities. By default, files are not encrypted.

When used to generate message digest 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 the SHA1 and other message digest algorithms. The message digest 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(1) and ntpdc(1) 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
password for local encrypted files and the -q option the password for encrypted files sent to remote
sites. If no password is specified, the host name returned by the Unix gethostname() function, normally
the DNS name of the host is used.

The pw option of the crypto configuration command specifies the read password for previously encrypted
local files. This must match the local password used by this program. If not specified, the host name
is used. Thus, if files are generated by this program without password, they can be read back by ntpd
without password but only on the same host.

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. The
location of the keys directory can be changed by the keysdir configuration command in such cases.
Normally, this is in /etc.

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
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 with expiration date one year hence. If run again without options, the
program uses the existing keys and parameters and generates only a new certificate with new expiration
date one year hence.

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.

The ntpd(8) configuration command crypto pw password specifies the read password for previously encrypted
files. The daemon expires on the spot if the password is missing or incorrect. For convenience, if a
file has been previously encrypted, the default read password is the name of the host running the
program. If the previous write password is specified as the host name, these files can be read by that
host with no explicit password.

File names begin with the prefix ntpkey_ and end with the postfix _hostname.filestamp, where hostname is
the owner name, usually the string returned by the Unix gethostname() routine, 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.

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 file name extensions, the files for a NFS 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 follows it to
the file name to extract the filestamp. If a link is not present, ntpd(8) 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 timestamp extension for all files generated at one time, so each
generation is distinct and can be readily recognized in monitoring data.

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. When run for the first time,
or if all ntpkey files have been removed, the program generates a RSA host key file and matching RSA-MD5
certificate file, 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, the program uses the same host key file,
but generates a new certificate file and 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 MD2, MD5, SHA, SHA1, MDC2 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 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 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. seconds. seconds.
s 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 often 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. f ntp-keygen is run
again without these options, it generates a new certificate using the same scheme and sign key.

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. However, if the host or sign key is changed, ntpd(8) should be
restarted. When ntpd(8) 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 described on the "Identification Schemes" page (maybe available at
http://www.eecis.udel.edu/%7emills/keygen.html). 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_RSAkey_alice.filestamp and trusted private certificate file
ntpkey_RSA-MD5_cert_alice.filestamp. 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.

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 mail program. Copy or mail 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 doesn't 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 cliens. 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
-c scheme
Select certificate message digest/signature encryption scheme. The scheme can be one of the
following: RSA-MD2, RSA-MD5, RSA-SHA, RSA-SHA1, RSA-MDC2, RSA-RIPEMD160, DSA-SHA, or DSA-SHA1.
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.

-d Enable debugging. This option displays the cryptographic data produced in eye-friendly
billboards.

-e Write the IFF client keys to the standard output. This is intended for automatic key
distribution by mail.

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

-g Generate keys for the GQ identification scheme using the existing GQ parameters. If the GQ
parameters do not yet exist, create them first.

-H Generate new host keys, obsoleting any that may exist.

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

-i name
Set the suject name to name. This is used as the subject field in certificates and in the file
name for host and sign keys.

-M Generate MD5 keys, obsoleting any that may exist.

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

-p password
Encrypt generated files containing private data with password and the DES-CBC algorithm.

-q Set the password for reading files to password.

-S [RSA | 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.

-s name
Set the issuer name to name. This is used for the issuer field in certificates and in the file
name for identity files.

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

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

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. 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 other file formats begin with two lines. The first contains the file name, including the generated
host name and filestamp. The second contains the datestamp in conventional Unix date format. Lines
beginning with # are considered comments and ignored by the ntp-keygen program and ntpd(8) daemon.
Cryptographic values are encoded first using ASN.1 rules, then encrypted if necessary, and finally
written PEM-encoded printable ASCII format preceded and followed by MIME content identifier lines.

The format of the symmetric keys file is somewhat different than the other files in the interest of
backward compatibility. Since DES-CBC is deprecated in NTPv4, the only key format of interest is MD5
alphanumeric strings. Following hte heard the keys are entered one per line in the format
keyno type key
where keyno is a positive integer in the range 1-65,535, type is the string MD5 defining the key format
and key is the key itself, which is a printable ASCII string 16 characters or less in length. Each
character is chosen from the 93 printable characters in the range 0x21 through 0x7f excluding space and
the ‘#’ character.

Note that the keys used by the ntpq(1) and ntpdc(1) 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 MD5 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(1) and ntpdc(1) 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-SHA, RSA-SHA1, RSA-MDC2, RSA-RIPEMD160, DSA-SHA, or
DSA-SHA1.

Select the certificate message digest/signature encryption 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 "@code{-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 IFF or GQ client keys to the standard output. This is intended for automatic key
distribution by mail.

-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's subject and issuer names in
the form host@group and should match the ´crypto ident' or 'server ident' configuration in ntpd's
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, --md5key
generate MD5 keys.

Generate MD5 keys, obsoleting any that may exist.

-m modulus, --modulus=modulus
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.

-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 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.

-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's 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.

-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

       The -p password option specifies the write  password  and  -q  password  option  the  read  password  for
       previously  encrypted  files.   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.

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) 1992-2017 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, from one to several minutes with  modern
       architectures  such  as  UltraSPARC and up to tens of minutes to an hour with older architectures such as
       SPARC IPC.

       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.

Debian                                            March 21 2017                                    NTP_KEYGEN(8)