Content-sharing in digital rights management

Designers of digital rights management systems have several options for implementing a controlled degree of sharing of digital objects between users. Each model described in this chapter takes a somewhat different approach, and may be better suited to some circumstances than others: authorised domains capture the notion of a personal, household or office collection of devices; rights transfer protocols mimic the behaviour of works stored on physical media; super-distribution models monetise sharing amongst users; rights lockers capture the notion of ownership of an item of intellectual property; and proximity sharing introduces new possibilities for discovering and sharing art and information. The technologies can, in general, be combined: Coral, for example, uses a rights locker to manage rights in an authorised domain, and it is easy to imagine systems that transfer rights from one rights locker or authorised domain to another. Combined or individually, none of the technologies described in this chapter completely replicate the behaviour of physical media, though rights transfer protocols are arguably close in concept. On one hand, new models of distribution can confuse and frustrate users because they cannot use rights-managed material in the ways that they have come to expect. On the other hand, new technology has the potential to support business models, organisational practices and social behaviours that were not possible using older technology. The authorised domain model is probably the most mature technology described in this chapter, and is probably the most widely deployed. In principle, domains can represent any collection of devices, though most existing visions consider only domains that represent households or individuals. We are not aware of any work that explicitly attempts to identify what users might perceive to be a reasonable definition of a "domain". Interest in rights lockers has increased over the past few years, and lockers are an obvious mechanism for implementing models in which users "own" rights to use digital objects: so long as their devices can connect to Internet, users can exercise their rights anywhere and on any device. The need to connect to the locker may have been a significant barrier to services of this kind in the past, when access to the Internet was comparatively restricted. As Internet connectivity becomes cheaper and more pervasive, however, rights lockers may become more appealing. While the great majority of published papers and specifications for digital rights management systems focus on protection of copyright, rights management also has a place in organisational settings. The requirements for sharing amongst organisations and work colleagues are somewhat different for those for copyright protection, but only a very small number of works so far attempt to address sharing within or amongst organisations.