Web development question
I am putting together a website and the client would like to have a pay-per-download area. I know how to do the member login part, so they have a members area, but I'm not sure about the pay-per-download. They want to use PayPal, and then have the link download. How do you stop that link from being passed around? How do you make sure no one else can download/see the link unless they are signed in and paid? Anyone have any idea?