Data processing

A user has a key (5) which may, for example, be in the form of a smart card or SIM used in a cellular telephone system. The user obtains content (6) from a Content Provider. The content comprises encrypted data recorded, for example, on suitable media - such as, for instance, audio or video content recorded on a DVD or CD. A hardware device (8) is in principle capable of receiving the media (6), decrypting it and allowing the user to play it or otherwise "consume" it. The hardware (8) contains a suitable application (10) in the form of software for enabling the content to be played when authorised. If the application (10) is an "approved application" (that is, trusted software from a known software provider), a licensing system (12) can provide the key (5) with a licence for allowing the content to be decrypted and consumed by the application (10) on the device (8), subject to a user authentication process. The licence is therefore not restricted to a particular device (8) but to a particular approved application.