Question : hide a txt file

Hi. I have a commercial sofware that is able to log events in a txt file. My goal is to avoid that someone may modify it,  in other word only the application is allowed to update the log file. How I can do that? I was thinking to create the txt log file as hidden file...Any idea? This application run on Windows 2003 sp2.

Thx

Answer : hide a txt file

So give just Administrator access and the users shouldn't be able to change the file, unless they are logging on as Administrator.