Text file problem


I have a project on hand that need to use text file to store some important informations instead of using database. So when i place it and test it in my localhost, i can access the text file by just simply type the url of the txt file. This let others to see the content of it, i cannot let others to view the content since it was confidential.

In this text file, it allow user to write into it using a form, but for viewing purpose it suppose to allow administrator to see it, while public user cannot view it.

So, the question is how to make it work that allow the content to be updated by public but not allow them to view it. Only the admin user can view it. I'm using IIS ver6. Do i need to do any configuration or write any code? And I'm using ASP to do the site.