Hello. Sorry for my bad english.
I am going to store files on my server.
When the buyer has paid the purchase, he gets a link to the file. In that case, if the file is on my server, the link turns out like this:
www.mysite.com/file.ext?unique_parameters_which_added_by_ejunkie
It turns out that dropping these parameters, the user will be able to download this file multiple times. Tell us how we can provide a truly unique link, and not only the unique parameters og GET-line?