You can use a Formmail script and PHP which can be downloaded from www.boaddrink.com/projects/phpformmail/index.php
A simple demo Form that can be viewed via www.easyzone.net/phpformmail/ which has instructions on this Form on how to use it with the PHP Formmail script
To compare you can see a simple normal CGI Form via http://www.easyzone.net/formtest.html
The information you need to setup PGP and Formmail is available at www.verysimple.com/products.php/simplesecure.html