An interesting way to copy-protect discs

Macrovision has come out with an interesting way to deter piracy of games/movies. Of course, it's impossible to prevent discs from being copied bit-by-bit unless all hardware is designed to prevent that - something that is practically impossible. The region encoding in DVDs doesn't really work outside in the US. It's extremely easy to obtain DVD players (or even get hacked players from big name brands) in Asia that do not look for the region information in DVDs and hence, will play almost any DVD.

Now this method tries something really interesting. Almost all CD/DVD systems have error correction mechanisms so that discs with minor scratches or dust will still play fine. The macrovision method puts bit sequences on the disk that appear as minor scratches to the player. The bits do not worry the original game/movie which is designed to look out for those bits, but as soon as the disk is copied, those virtual 'scratches' are lost - which signals that the disk is a copied one.

The interesting part about the technology is that instead of completely disabling the software, the games are designed to progressively deteriorate over time if it detects that a pirated version is running. So guns might not aim properly, or balls on a pool table might not have enough gravity to keep them on the table - all this happens after a while, and in stages so that the player is properly hooked to the game by then. It is assumed that the player will be sufficiently interested to go out and buy a proper version to keep playing. For movies, the idea is to stop playing the movie at some interesting point.

Of course, no system can ever be completely hacker proof, but the very concept of having pirated software disintegrate over time, much like a low-quality pirated book is innovative.