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 1-65534;
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) 1992-2017 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.
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.