| Updated: April 19, 2023 |
Generate cryptographic data files used by NTPv4
ntp-keygen [-flags] [-flag [value]] [--option-name[[=| ]value]]
QNX Neutrino
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 soft-
ware 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 identi-
fication algorithms compatible with the Internet standard security in-
frastructure.
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 algo-
rithms. 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) utility programs.
The remaining generated files are compatible with other OpenSSL appli-
cations and other Public Key Infrastructure (PKI) resources. Certifi-
cates 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 pass-
word, 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 usu-
ally 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 std-
out 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.
This program uses the OpenSSL library for cryptography services.
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 con-
figure it to synchronize from reliable Internet servers. Then config-
ure the other hosts to synchronize to the TH directly or indirectly. A
certificate trail is created when Autokey asks the immediately ascen-
dant host towards the TH to sign its certificate, which is then pro-
vided 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 signa-
ture message digest type is MD5, but any combination of sign key type
and message digest type supported by the OpenSSL library can be speci-
fied 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-gener-
ated.
Additional information on trusted groups and identity schemes is on the
Autokey Public-Key Authentication page.
The ntpd(1) 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 gen-
erated 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(1) 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, usu-
ally /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 pro-
gram 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 speci-
fied 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, includ-
ing 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. Certifi-
cates 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. How-
ever, 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.
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(1) 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, usu-
ally /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 pro-
gram 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 speci-
fied 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, includ-
ing 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. Certifi-
cates 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. How-
ever, 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 certifi-
cate 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 Configura-
tion 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 cer-
tificates. When complete, start the NTP daemons beginning at the low-
est stratum and working up the tree. It may take some time for Autokey
to instantiate the certificate trails throughout the subnet, but set-
ting up the environment is completely automatic.
If it is necessary to use a different sign key or different digest/sig-
nature 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(1) should be restarted. When ntpd(1) is restarted, it loads any
new files and restarts the protocol. Other dependent hosts will con-
tinue as usual until signatures are refreshed, at which time the proto-
col 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 non-
trusted 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 ntp-
key_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 cer-
tificate 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_IFF-
par_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 cer-
tificates 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 ntp-
key_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 ntp-
keys_MVpar_trish.filestamp and client key files ntp-
keys_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: 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 exist-
ing GQ parameters. If the GQ parameters do not yet exist, cre-
ate them first.
-H Generate new host keys, obsoleting any that may exist.
-I Generate parameters for the IFF identification scheme, obsolet-
ing 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 gener-
ates 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 gener-
ates a non-trusted certificate.
-V nkeys
Generate parameters and keys for the Mu-Varadharajan (MV) iden-
tification scheme.
Random Seed File
All cryptographically sound key generation schemes must have means to
randomize the entropy seed used to initialize the internal pseudo-ran-
dom 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 pre-
dictable. Various means dependent on external events, such as key-
stroke 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 dae-
mon 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 can-
not 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 begin-
ning with # are considered comments and ignored by the ntp-keygen pro-
gram and ntpd(1) 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 alphanu-
meric 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 charac-
ter 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) 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 ntp-
key_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. Sub-
sequently, 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) 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 unlim-
ited 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, obsolet-
ing 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 ntpd's config-
uration 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 gener-
ates 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 host-
name.
-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 leav-
ing the host name unchanged while appending @group to the sub-
ject 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 gener-
ates a non-trusted certificate.
-V num, --mv-params=num
generate <num> MV parameters. This option takes an integer num-
ber as its argument.
Generate parameters and keys for the Mu-Varadharajan (MV) iden-
tification 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 con-
figuration 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 load-
ing 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-key-
gen 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
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.