1. A digital rights management system for digital broadcasting based on home servers IEEE TRANACTIONS ON BROADCASTING, VOL.52, NO.2, JUNE 2006 Yusei Nishimoto, Akitsugu Baba, Tatsuya Kurioka, and Seiichi Namba

2. Outline  Introduction  Problems with DRM system  Novel DRM system  Prototype DRM system for evaluation  Experimental results for Non-Linear playback  Experimental results for Fast-Forward playback  Conclusion

3. Introduction  DBHS will enable viewers to enjoy ‘television anytime/anywhere’ by utilizing receivers with large- capacity storage devices.  Conventional broadcasting systems have used the conditional access (CA) technique to protect the rights of broadcasting content sent from the broadcaster to the receives.

4. Problems with DRM system  CA system cannot safeguard stored content.  When playing stored content, the viewer also requires functions such as nonlinear playback and ‘trick-play’ modes.

5. Novel DRM system  The protection of content and decryption keys.  Advanced access control of individual stored content should be possible.  The reception of conventional digital broadcasting by the DRM system should be possible.  Nonlinear playback and trick-play functions, even in the case of content protected by DRM systems, should be feasible.

6. Novel DRM system  A scramble key (Ks) encrypts the content and changes approximately once per second.  A work key (Kw) is unique to each individual broadcaster.  A master key (Km) is unique to the security module of receiver.

7. Novel DRM system ECM section

8. Novel DRM system

10. Prototype DRM system for evaluation

11. Experimental results for Non-Linear playback The nonlinear playback of content encrypted using the four encryption keys could be processed in real time.

12. Experimental results for Fast-Forward playback Fast-forward playback mechanism for encrypted contents by four encryption key.

13. Experimental results for Fast-Forward playback Evaluated ECM-Kc sending method.

14. Experimental results for Fast-Forward playback  The system achieve functionality equal to, or greater than, that of commercially available hard disk records.

15. Conclusion  Novel DRM system enables conventional viewing during broadcasting reception and achieves usage control for viewing after storage.  Novel DRM system is suitable ‘one-to-many’ content transmission.