121 lines
3.3 KiB
Groff
121 lines
3.3 KiB
Groff
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 13, 2000
|
|
.Dt NTP.KEYS 5
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ntp.keys
|
|
.Nd NTP daemon key file format
|
|
.Sh SYNOPSIS
|
|
.Nm /etc/ntp.keys
|
|
.Sh DESCRIPTION
|
|
Following is a description of the format of NTP key files.
|
|
For a description of the use of these files, see the
|
|
.Qq Authentication Support
|
|
section of the
|
|
.Xr ntp.conf 5
|
|
page.
|
|
.Pp
|
|
In the case of DES, the keys are 56 bits long with,
|
|
depending on type, a parity check on each byte.
|
|
In the case of MD5, the keys are 64 bits (8 bytes).
|
|
.Xr ntpd 8
|
|
reads its keys from a file specified using the
|
|
.Fl k
|
|
command line option or the
|
|
.Ic keys
|
|
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 of the keys numbered 1 through 15
|
|
may be arbitrarily set in the keys file.
|
|
.Pp
|
|
The key file uses the same comment conventions
|
|
as the configuration file.
|
|
Key entries use a fixed format of the form
|
|
.Pp
|
|
.D1 Ar keyno type key
|
|
.Pp
|
|
where
|
|
.Ar keyno
|
|
is a positive integer,
|
|
.Ar type
|
|
is a single character which defines the key format,
|
|
and
|
|
.Ar key
|
|
is the key itself.
|
|
.Pp
|
|
The
|
|
.Ar key
|
|
may be given in one of three different formats,
|
|
controlled by the
|
|
.Ar type
|
|
character.
|
|
The four key types, and corresponding formats,
|
|
are listed following.
|
|
.Bl -tag -width X
|
|
.It Li S
|
|
The key is a 64-bit hexadecimal number in the format
|
|
specified in the DES specification;
|
|
that is, the high order seven bits of each octet are used
|
|
to form the 56-bit key
|
|
while the low order bit of each octet is given a value
|
|
such that odd parity is maintained for the octet.
|
|
Leading zeroes must be specified
|
|
(i.e., the key must be exactly 16 hex digits long)
|
|
and odd parity must be maintained.
|
|
Hence a zero key, in standard format, would be given as
|
|
.Ql 0101010101010101 .
|
|
.It Li N
|
|
The key is a 64-bit hexadecimal number in the format
|
|
specified in the NTP standard.
|
|
This is the same as the DES format,
|
|
except the bits in each octet have been rotated one bit right
|
|
so that the parity bit is now the high order bit of the octet.
|
|
Leading zeroes must be specified and odd parity must be maintained.
|
|
A zero key in NTP format would be specified as
|
|
.Ql 8080808080808080 .
|
|
.It Li A
|
|
The key is a 1-to-8 character ASCII string.
|
|
A key is formed from this by using the low order 7 bits
|
|
of each ASCII character in the string,
|
|
with zeroes added on the right
|
|
when necessary to form a full width 56-bit key,
|
|
in the same way that encryption keys are formed from
|
|
.Ux
|
|
passwords.
|
|
.It Li M
|
|
The key is a 1-to-8 character ASCII string,
|
|
using the MD5 authentication scheme.
|
|
Note that both the keys and the authentication schemes (DES or MD5)
|
|
must be identical between a set of peers sharing the same key number.
|
|
.El
|
|
.Pp
|
|
Note that the keys used by the
|
|
.Xr ntpq 8
|
|
and
|
|
.Xr ntpdc 8
|
|
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
|
|
.Bl -tag -width /etc/ntp.drift -compact
|
|
.It Pa /etc/ntp.keys
|
|
the default name of the configuration file
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ntp.conf 5 ,
|
|
.Xr ntpd 8 ,
|
|
.Xr ntpdate 8 ,
|
|
.Xr ntpdc 8
|
|
.Sh BUGS
|
|
.Xr ntpd 8
|
|
has gotten rather fat.
|
|
While not huge, it has gotten larger than might
|
|
be desireable for an elevated-priority daemon running on a workstation,
|
|
particularly since many of the fancy features which consume the space
|
|
were designed more with a busy primary server, rather than a high
|
|
stratum workstation, in mind.
|