In order to build the Photuris daemon you need the following libraries
 - gmp-2.0.2
 - libdes-4.0.1

You can find the sources for the above library also at the following
location: http://www.physnet.uni-hamburg.de/provos/photuris/

Compile them and change the directories in the Makefile accordingly.
Look for the right definitions for your OS in the Makefile. At the moment
there are sections for AIX, Solaris, Linux and OpenBSD. 
For Security Associations to be setup in the kernel you need to
add -DIPSEC to the CFLAGS.

Run make.

After starting the photurisd on two machines, you can start the program
startkey dst=<ip-number-of-the-other-machine> to start a key exchange.

For the daemon to work with other IPSec implementations you should look
in the sources for #ifdef IPSEC.

You might also want to customize the following files:
photuris.conf
attributes.conf
secrets.conf

If you compiled the daemon without -DDEBUG, you also need an
entry in /etc/services like that:
photuris	468/udp		# photuris keymangement daemon

More complete instructions can be found in README.howtouse