Abstract: In Authorized Domains the management of which devices that can access content is a key issue. The Authorized Domain must be limited to a relatively small group of devices to get a solution that is acceptable to both content providers and users. However, current solutions are typically either to rigid to be future proof and user friendly or not effective enough in limiting the size of the Authorized Domain. This invention provides a user-friendly, flexible and yet effective method of managing the size of an Authorized Domain. The method proposes to group devices in the Authorized Domain into clusters, if a predetermined requirement is met, and to limit the number of clusters. Such a predetermined requirement could be a proximity requirement.

Abstract: The invention relates to a data carrier (DC) for carrying a data content (CONT) belonging to an authorized domain (AD). Said data carrier (DC) comprises a data carrier data right management system (M-DRM) ruled by first rights (R1) of exporting said data content (CONT) to a reading apparatus (RA). Said authorized domain comprises a domain data right management system (AD-DRM) ruled by second rights (R2) of exporting said data content (CONT) to a reading apparatus (RA), said second rights depending on whether the reading apparatus belongs to the authorized domain. The data carrier (DC) comprises said data content (CONT) stored within a data carrier data content file (CCF) having a data carrier format specified by said data carrier data right management system (M-DRM), a data carrier license (ML) comprising said first rights (R1) and a domain license (DL) comprising said second rights (R2), said domain license (DL) being stored as a data carrier domain license file (CDLF) having said data carrier format.

Abstract: To ensure that digital rights cannot be forged or tampered with, they can be digitally signed. However, this means that updating the digital rights is no longer possible, as this would invalidate the digital signature. The present invention proposes that the issuer of digital rights issues rights which are signed in elementary pieces, rather than as a whole. Rather than issuing a right to play back a piece of content three times, the provider issues for example three rights to play back the content once in a particular AD, of which two may be transferred to other domains. The digital rights are individually protected by signatures and it is no longer possible to forge digital rights. As an enhancement the rights that can be transferred are indicated as such and stored securely to prevent tampering. When the right is transferred, it must be signed by the person who originally received it.