I need the same thing. Let me know if you find an answer.
Somwhere in future i need same thing as well.
I guess it should work over C-level extensibility: http://help.adobe.com/en_US/dreamweaver/cs/extend/WS5b3ccc516d4fbf351e63e3d117f508c8de-7f6 6.html
Because C-files compiled to '.dll-s what is not human readable.
You will write key check functionality in C,
compail dll files,
make you exstension work so, its not working without .dll files.
I'm not sure if this a right way to do.
All other ideas is welcome.