Spreadsheet Security

I have a spreadsheet that contains confidental information that I want to
share for analysis. I will place it in a shared network folder (secured). I do not want anyone to be able to save, email, copy or update the spreadsheet, other than the owner of the file. This is for viewing only. Has anyone done it or am I wasting my time? The excel security is not sufficeint.

Pretty much wasting your time. Anyone could take screen grabs if the data were important enough to them