This is a Sharepoint Services v 3.0 project that integrates a digital signature document format ( DigiDoc, see http://www.sk.ee/pages.php/020305010101 )
The project consists of two Features including document libary event handler, custom pages for performing digital signature operations, and a custom IFilter implementation ( C++ ) to provide full-text search for the given file format.
There is also a site-wide customization of document library context menus and some other generally useful pieces of code for WSS 3.0
The packaging format is WSS 3.0 introduced Sharepoint Solution in form of a WSP file.