.TH ntp.keys 5 "06 Jun 2023" "4.2.8p17" "File Formats"
.\"
.\"  EDIT THIS FILE WITH CAUTION  (ntp.man)
.\"
.\"  It has been AutoGen-ed  June  6, 2023 at 04:37:47 AM by AutoGen 5.18.16
.\"  From the definitions    ntp.keys.def
.\"  and the template file   agman-file.tpl
.Sh NAME
.Nm ntp.keys
.Nd NTP symmetric key file format

.\"
.SH NAME
ntp.keys \- NTP symmetric key file format configuration file
.de1 NOP
.  it 1 an-trap
.  if \\n[.$] \,\\$*\/
..
.ie t \
.ds B-Font [CB]
.ds I-Font [CI]
.ds R-Font [CR]
.el \
.ds B-Font B
.ds I-Font I
.ds R-Font R
.SH SYNOPSIS
\f\*[B-Font]\fP
[\f\*[B-Font]\-\-option-name\f[]]
[\f\*[B-Font]\-\-option-name\f[] \f\*[I-Font]value\f[]]
.sp \n(Ppu
.ne 2

All arguments must be options.
.sp \n(Ppu
.ne 2

.SH DESCRIPTION
This document describes the format of an NTP symmetric key file.
For a description of the use of this type of file, see the
"Authentication Support"
section of the
\fCntp.conf\f[]\fR(5)\f[]
page.
.sp \n(Ppu
.ne 2

\fCntpd\f[]\fR(8)\f[]
reads its keys from a file specified using the
\f\*[B-Font]\-k\f[]
command line option or the
\f\*[B-Font]keys\f[]
statement in the configuration file.
While key number 0 is fixed by the NTP standard
(as 56 zero bits)
and may not be changed,
one or more keys numbered between 1 and 65535
may be arbitrarily set in the keys file.
.sp \n(Ppu
.ne 2

The key file uses the same comment conventions
as the configuration file.
Key entries use a fixed format of the form
.sp \n(Ppu
.ne 2

.in +4
\f\*[I-Font]keyno\f[] \f\*[I-Font]type\f[] \f\*[I-Font]key\f[] \f\*[I-Font]opt_IP_list\f[]
.in -4
.sp \n(Ppu
.ne 2

where
\f\*[I-Font]keyno\f[]
is a positive integer (between 1 and 65535),
\f\*[I-Font]type\f[]
is the message digest algorithm,
\f\*[I-Font]key\f[]
is the key itself, and
\f\*[I-Font]opt_IP_list\f[]
is an optional comma-separated list of IPs
where the
\f\*[I-Font]keyno\f[]
should be trusted.
that are allowed to serve time.
Each IP in
\f\*[I-Font]opt_IP_list\f[]
may contain an optional
\f\*[B-Font]/subnetbits\f[]
specification which identifies the number of bits for
the desired subnet of trust.
If
\f\*[I-Font]opt_IP_list\f[]
is empty,
any properly-authenticated message will be
accepted.
.sp \n(Ppu
.ne 2

The
\f\*[I-Font]key\f[]
may be given in a format
controlled by the
\f\*[I-Font]type\f[]
field.
The
\f\*[I-Font]type\f[]
\f[C]MD5\f[]
is always supported.
If
\f[C]ntpd\f[]
was built with the OpenSSL library
then any digest library supported by that library may be specified.
However, if compliance with FIPS 140-2 is required the
\f\*[I-Font]type\f[]
must be either
\f[C]SHA\f[]
or
\f[C]SHA1\f[].
.sp \n(Ppu
.ne 2

What follows are some key types, and corresponding formats:
.sp \n(Ppu
.ne 2

.TP 7
.NOP \f[C]MD5\f[]
The key is 1 to 16 printable characters terminated by
an EOL,
whitespace,
or
a
\f[C]#\f[]
(which is the "start of comment" character).
.sp \n(Ppu
.ne 2

.br
.ns
.TP 7
.NOP \f[C]SHA\f[]
.br
.ns
.TP 7
.NOP \f[C]SHA1\f[]
.br
.ns
.TP 7
.NOP \f[C]RMD160\f[]
The key is a hex-encoded ASCII string of 40 characters,
which is truncated as necessary.
.PP
.sp \n(Ppu
.ne 2

Note that the keys used by the
\fCntpq\f[]\fR(8)\f[]
and
\fCntpdc\f[]\fR(8)\f[]
programs are checked against passwords
requested by the programs and entered by hand,
so it is generally appropriate to specify these keys in ASCII format.
.SH FILES
.TP 14
.NOP \fI/etc/ntp.keys\f[]
the default name of the configuration file
.PP
.SH "SEE ALSO"
\fCntp.conf\f[]\fR(5)\f[],
\fCntpd\f[]\fR(1)\f[],
\fCntpdate\f[]\fR(1)\f[],
\fCntpdc\f[]\fR(1)\f[],
\fCsntp\f[]\fR(1)\f[]
.SH "AUTHORS"
The University of Delaware and Network Time Foundation
.SH "COPYRIGHT"
Copyright (C) 1992-2023 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>.
.SH "BUGS"
Please send bug reports to: https://bugs.ntp.org, bugs@ntp.org
.SH NOTES
This document was derived from FreeBSD.
.sp \n(Ppu
.ne 2

This manual page was \fIAutoGen\fP-erated from the \fBntp.keys\fP
option definitions.