How to protect xml file

Question

 

I have a windows application in C#.net.In my application there is a xml file which is updated on every 30 seconds by the application automatically.I don't want the external user to update or tamper the xml file.So how can I protect the xml file so that other users can not read or update the xml file. I want the xml file to be updated automatically by the Application only.


Help me.

Thanks in advance.