Provided by: libreswan_4.7-1ubuntu1_amd64 bug


       ipsec_rsasigkey - generate RSA signature key


       ipsec rsasigkey [--verbose] [--seeddev device] [--seed numbits] [--nssdir nssdir]
             [--password nsspassword] [--hostname hostname] [nbits]


       rsasigkey generates an RSA public/private key pair, suitable for digital signatures, of
       (exactly) nbits bits (that is, two primes each of exactly nbits/2 bits, and related
       numbers) and emits it on standard output as ASCII (mostly hex) data.  nbits must be a
       multiple of 16.

       The public exponent is forced to the value 3, which has important speed advantages for
       signature checking. Beware that the resulting keys have known weaknesses as encryption
       keys and should not be used for that purpose.

       The --verbose option makes rsasigkey give a running commentary on standard error. By
       default, it works in silence until it is ready to generate output.

       The --seeddev option specifies a source for random bits used to seed the crypto library's
       RNG. The default is /dev/random (see random(4)). FreeS/WAN and Openswan without NSS
       support used this option to specify the random source used to directly create keys.
       Libreswan only uses it to seed the NSS crypto libraries RNG. Under Linux with hardware
       random support, special devices might show up as /dev/*rng* devices. However, these should
       never be accessed directly using this option, as hardware failures could lead to extremely
       non-random values (streams of zeroes have been observed in the wild)

       The --seedbits option specifies how many seed bits are pulled from the random device to
       seed the NSS PRNG. The default of 480bit comes from FIPS requirements. Seed bits are
       rounded up to a multiple of 8.

       The use of a different random device or a reduction of seedbits from the default value is
       prevented when the system is running in FIPS mode.

       The --nssdir option specifies the directory to use for the nss database. This is the
       directory where the NSS certificate, key and security modules databases reside. The
       default value is /var/lib/ipsec/nss.

       The --password option specifies the nss cryptographic module authentication password if
       the NSS module has been configured to require it. A password is required by hardware
       tokens and also by the internal software token module when configured to run in FIPS mode.
       If the argument is /etc/ipsec.d/nsspassword, the password comes from that file; otherwise
       argument is the password.

       The US patent on the RSA algorithm expired 20 Sept 2000.


       ipsec rsasigkey --verbose 4096
           generates a 4096-bit signature key and stores this key in the NSS database. The public
           key can then be extracted and edited into the ipsec.conf (see ipsec_showhostkey(8)).


       /dev/random, /dev/urandom


       random(4), rngd(8), ipsec_showhostkey(8), Applied Cryptography, 2nd. ed., by Bruce
       Schneier, Wiley 1996, RFCs 2537, 2313, GNU MP, the GNU multiple precision arithmetic
       library, edition 2.0.2, by Torbj Granlund


       Originally written for the Linux FreeS/WAN project <> by Henry
       Spencer. Updated for the Libreswan Project by Paul Wouters.

       The --round and --noopt options were obsoleted as these were only used with the old
       non-library crypto code

       The --random device is only used for seeding the crypto library, not for direct random to
       generate keys


       There is an internal limit on nbits, currently 20000.

       rsasigkey's run time is difficult to predict, since /dev/random output can be arbitrarily
       delayed if the system's entropy pool is low on randomness, and the time taken by the
       search for primes is also somewhat unpredictable. Specifically, embedded systems and most
       virtual machines are low on entropy. In such a situation, consider generating the RSA key
       on another machine, and copying ipsec.secrets and the /var/lib/ipsec/nss directory tree to
       the embedded platform. Note that NSS embeds the full path in the DB files, so the path on
       proxy machine must be identical to the path on the destination machine.


       Paul Wouters
           placeholder to suppress warning