Restrict user by not allowing to copy or move file to other location other than his downloaded one using dotnet

Following is the security that I need to implement:

 1) User downloads the excel file to his desktop from a website. (No issues)

2) Once downloaded user should be able to open and do changes and save. (No issues)

3) He should not be able to copy or move file to other location other than his downloaded one. (Need help on this requirement)

Can you please suggest how can I acheive 3rd requirement using dotnet? Please suggest how can I approach to acheive above requirement? If any alternative solution please suggest on same?

Thanks

Ameer
...