I thought about how to do an extra security precaution for key codes and such... I'm sure that someone has done it before but here it is...
Make a sort of dummy program that you would have as your main download file... now have it so that it is the program that you register the game or program with... (with the user first having to enter their keycode) then have the program log into a server with the ip address and keycode; I would say that if you notice a large amount of users using the same keycode its safe to assume that it has been either hacked or leached :P) Now because the program would just be a small downloader most people who were not too familiar with computer protocol wouldn't ever know the actual download location... and even then you could rename or rotate the file location (so you do not have to re-upload) and then change the download location in the small downloader to match the main download location...
Of course this wouldn’t faze much if you had a very small download file (though it would be convenient to package your programs with small downloader's so they don’t have to worry about getting disconnected)

Has anyone tried this?

/pkeod