Restricting Some Features Dynamically

Hello,

I am experimenting with restricting some features dynamically in opened
OOo documents.

For instance spreadsheet X would have its printing disabled, whereas
Writer document Y would have editing disabled.

The disabling of rights should happen when the document is opened.

There are two ways that I can see: having an extension coded with UNO
(doesn't look too easy to do that) or adding something to the core,
maybe as a dedicated file format handler.

Is there any other way to do it? Which way is simpler to implement?

Regards,

-- 
Marc-André Laverdière
Software Security Scientist
Innovation Labs, Tata Consultancy Services
Hyderabad, India