A number of defensive methods have been created to counter copyright infringement of digital products. They are known collectively as Digital Rights Management (DRM).
This is a large area but the greatest and most visible use is the prevention of copying of movies from DVDs. This generally requires mechanisms to be active in one or both of the DVD disk itself and the DVD player or computer used.
- the need to keep a Satellite Television receiver box connected to the public telephone network.
- certain high definition film disks can only be played back on a computer which is connected to the internet.
- the latest large screen television displays need a special module to display high definition DVD movies. If this module is not present, the output from the DVD player is disabled. The presence of the module guarantees that the incoming digital signal is not being copied.
- regional coding of DVDs prevents a DVD disk purchased in the USA from being played on a European region DVD player.
Digital watermarking involves inserting an encrypted digital code into an image. It is of particular use with images which are placed on websites and thus easily copied. It is invisible to the casual user but provides a tracking mechanism for owners. It is a digital code, which can be unique to the image or used for all the owner’s images.
Digital fingerprints are unique labels inserted into different copies of the same content (eg: an e-book, video or music file) prior to distribution. Each digital fingerprint is assigned to a specific recipient, and thus provides the capability to trace those who use their content for unintended purposes. Fingerprints are closely associated with the content and difficult to remove.
Next: The Data Protection Act