Methods of and devices (D1) for authorizing an operation requested by a first user (P2) on a content item (C1) in accordance with a user right (UR1). The user right may identify the first user or a second user (P) and authorizes the user in question to perform the requested operation on the content item....http://www.google.com.au/patents/US20060021065?utm_source=gb-gplus-sharePatent US20060021065 - Method and device for authorizing content operations
