My ASP Paypal E-Goods ProtectorPaypal's \"return url\" variables is very hacker friendly, everyone knows this, even Paypal. I developed this software to protect my own applications, after each successful payment, the download url is sent automatically by email to the customer.
MA.P.E.P. is written in ASP/VBscript using Macromedia Ultradev, it is 100% customizable and extendible. Easy straight forward setup.