Research On DRM System For Streamed MPEG-4 Media

With the wide application of streaming media in network, Streaming media DRM (Digital Rights Management) has attracted more and more attention so as to become a research hot spot. In particular, DRM technology has just been started in domestic circumstance, so the study of DRM for streaming media is of great significance.Grasping the core technology of streaming media DRM not only needs to understand the process of from making media to playing media deeply but also deal well with the problem of encrypting streaming media files. In the thesis, a frame of DRM for streamed MPEG-4 media is proposed based on triple level encryption mechanism, several methods of encrypting MPEG-4 are studied, and the server and client of DRM system for streamed MPEG-4 media are designed in detail. Main works and contributions are outlined as follows.Firstly, functional models of server and client in this DRM system are built. The main function of server is user information management, authorization and MPEG-4 files content encryption. The client's function is to decrypt the streaming media data received from internet, and then play it. In this thesis, tripe level encryption mechanism is proposed. It is a mixed key system which includes Content Key, Service Key and User Key, ensuring the security of this DRM system effectively.Secondly, a new method of encrypting MPEG-4 files without breaking file format is proposed based on the analysis of encryption technology of streaming media, encryption algorithms of MPEG and MPEG-4 data format, and four means of encrypting MPEG-4 using Content Key are designed.Finally, this thesis also designs the streaming media server, content packaging server and authorization server. A steaming media player with DRM is implemented based on DirectShow.