I was wondering if i could implement some type of authentification to disallow the downloading of certain files....

What i'm trying to do is implement a downloading system based on user accounts...something like Rapidshare..but just the basic : ask for the user pass before downloading...
it would be nice if i could implement this through a PHP or page
but i don't want to serve with PHP ..through headers, because then nginx won't take over the serving of the files, and resume won't be available, of course the performance will be affeceted very badly

Thank you for your replies

Cris