Interoperable systems and methods for peer-to-peer service orchestration

Systems and methods for managing access to a piece of content in a peer-to-peer computing system are disclosed. A client device comprises a user interface (1000; 1210) for receiving a request from a user to access a piece of protected content, a host application (1002; 1200) for recognising a protected content object format and issuing a request to a digital rights management engine (1220) to evaluate digital rights management objects that make up a licence, and a digital rights management engine (1000; 1220) for executing the control program (1324) to determine whether permission to access the protected content should be granted. The licence comprises a set of objects that protect the content and govern its use, including a control object (1320), the control object including a control program (1324). Executing the control program comprises determining whether there exists a set of link objects (1420) representing relationships between nodes that can establish a path to a target node.