How to copyrighting a document after being downloaded by the users

I am a relatively new ASP.Net developer.I have involved in a project which needs a requirement as follows.
I have a document (document may be word document or a pdf document) in the server side.This document is not copyrighted and it is free to do whatever the modifications by the developers at the server side. When the users log into the web site, they are given a link to download this document and after they download the document what I want is the downloaded document should be copyrighted so that the downloaded user should only be able to view the document. That user should not be even cut or copy and paste the contents in the document to another document.I came across that this particular restrictions can be done to a word document using the available resources provided with MS Word.but I need to know whether this particular thing can be achieved through web.
can anyone suggest a solution plz.
Regards,
sumithmoratuwa 
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