A hacker has reportedly cracked high definition content protection and shared a "master key" on the world wide wibble. The master key means that the system no longer works, as hackers would now be able to create their own source and sink keys, both of which are needed to playback content on HDCP-protected devices.
It means that a perfect connection could always be ensured between transmitting and receiving devices. HDCP-protected content would be copyable.
The movie industry would be able to change the key, but since the hackers have the master key they could simply create a new active key, and build devices that could decode and copy content at its full quality. Furthermore, the studios would have a devil of a job revoking the key anyway as it would stop legitimate copies from working.
The system has been annoying the pants off iTunes users for two years. Some movies will not play on external displays due to those monitors not supporting HDCP. However since it is cheap as chips to set up it has proved popular.
For about a decade researchers were warning that it could be broken through reverse engineering. All the hacker needed was keys from about 50 or so devices.