This paper presents an ongoing Digital Right Management (DRM) standard: Digital Media Project (DMP), which is active as an interoperable DRM solution in recent three years. We start by reviewing the important works of DRM standards at present, mainly focusing on their interoperability issues. Then we describe the core techniques in DMP and explain how they fit into an interoperable DRM system. We also give a report on the development of the reference software of DMP – Chillout, which is an open source project. Finally, we outline several tasks that we will undertake in the next step of DMP to optimize this technical standard.