Do you need to protect uploaded files so they can only be viewed by logged-in users? If so, then check out our plugin for WordPress, MCM Protected File View.
This plugin does not work with the media library. It only protects files uploaded through the plugin itself.
Requires a web server that supports .htaccess files for access control, such as Apache on Linux.
If you're interested in helping develop this plugin, you're welcome to collaborate with us on GitHub.