I don't understand. There is a perfect copyright-protection system out there already. It's called Steam. Maybe there is a way around it, but I wouldn't know how, and I am more technical than 99% of their customers.
People who are willing to download a gigabyte on bittorrent and risk viruses and who knows what are people with lots of time and no money, anyways.
People who are willing to download a gigabyte on bittorrent and risk viruses and who knows what are people with lots of time and no money, anyways.