Hiawatha is a webserver for Unix and has been build with security in mind. This resulted in a highly secure webserver, in both code and features.
This webserver runs on Linux, BSD, MacOS X and Windows. Although it can run any kind of CGI / FastCGI application, it has been optimized for usage with PHP. Most well known PHP frameworks and CMS applications have been tested with Hiawatha and ran without a problem. Hiawatha supports many web and HTTP features such as CGI/FastCGI, HTTP authentication, virtual host support, request pipelining, keep alive connections, URL rewriting and many more. More information about its features can be found at the features page. If you are interested in some background information, visit the about page.
If you are interested in building secure websites, you should also take a look at the Banshee PHP framework.