Newhostkey outputs (into
filename , which can be `-' for standard output)
an RSA private key suitable for this host,
in
/etc/ipsec.secretsformat
(see
ipsec.secrets(5) ). Normally,
newhostkey invokes
rsasigkey (see
ipsec_rsasigkey(8) ) with the
--verbose option, so a narrative of what is being done appears on standard error.
The
--output specifier, although it is syntactically an option and can appear at
any point among the options (it doesn't have to be first),
is not optional.
The specified
filename is created under umask
077 if nonexistent;
if it already exists and is non-empty,
a warning message about that is sent to standard error,
and the output is appended to the file.
The
--quiet option suppresses both the
rsasigkey narrative and the existing-file warning message.
The
--bits option specifies the number of bits in the key;
the current default is 2192 and we do not recommend use of anything
shorter unless unusual constraints demand it.
The
--hostname option is passed through to
rsasigkey to tell it what host name to label the output with
(via its
--hostname option).
The output format is that of
rsasigkey , with bracketing added to complete the
ipsec.secrets format.
In the usual case, where
ipsec.secrets contains only the host's own private key,
the output of
newhostkey is sufficient as a complete
ipsec.secrets file.
Written for the Linux FreeS/WAN project
<http://www.freeswan.org>
by Henry Spencer.
BUGS
As with
rsasigkey , the run time is difficult to predict,
since depletion of the system's randomness pool can cause
arbitrarily long waits for random bits,
and the prime-number searches can also take unpredictable
(and potentially large) amounts of CPU time.
See
ipsec_rsasigkey(8) for some typical performance numbers.
A higher-level tool which could handle the clerical details
of changing to a new key would be helpful.
The requirement for
--output is a blemish,
but private keys are extremely sensitive information
and unusual precautions seem justified.
