Why not install Phorum5 instead? If security is an issue to you, you'll be better of with an application that is maintained than the officially no longer supported and maintained Phorum3.
As for instructions on how to setup the security for Phorum3, please read the docs/install.txt that was packaged in the distribution.
As for instructions on how to setup the security for Phorum3, please read the docs/install.txt that was packaged in the distribution.
