How to set a password for uploading files?

Question

htaccess

You need to put a password in the hosting category for downloading mp3 or zip files.
But the download will be from a C# program.
What ways are there to protect files from third-party downloads, for example, if they select a link, or simply somehow find out the link to the file
so that the files can only be downloaded by the program by pincode or authorization.
Tell me, preferably with examples

Answer 1

Give files by script, put the files themselves in a folder where there is no access via the web
On the side of the script, check access, the password is there or something else. And give, reading bytes into the output with the appropriate headers