1. Jau-Wu Huang1 Digital Rights Management for Visual Content in Mobile Applications Trimeche, M.; Chebil, F.; Nokia Research Center Control, Communications and Signal Processing, 2004. First International Symposium on, 2004. Pages:95 - 98

2. Jau-Wu Huang2 Outline Introduction DRM in OMA DRM for Mobile Visual Content Encryption Watermarking Watermarking of images and video Conclusion

3. Jau-Wu Huang3 Introduction Secure distribution, storage, exchange and management of copyright- protected contents Audio Video Game, … A balance between content owner and consumer’s rights

4. Jau-Wu Huang4 Conflicts of Rights Content Owners I create the content Revenue flow for every single copy sold No resale of content No copying of content Content used only by original buyer Limited use of content

5. Jau-Wu Huang5 Conflicts of Rights(Cont.) Consumers I paid for the content Fair use right to copy the content Resale the content in a different form Share contents with others Unlimited use of contents Why pay for something if I can get it free

6. Jau-Wu Huang6 DRM System End-to-end security Every link in the delivery chain has to be secured 2 major content distribution channels Distribution of electronic files via the Internet or digital bus interface Distribution via pre-recorded or recordable physical media Only accessible to authorized/authenticated person or compliance devices Rights are correctly executed and enforced

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8. 8 DRM Formula DRM = Contents + Rights + Enforcement Contents Audio track, VCD, DVD, … Rights Copy once, copy never, unlimited listening, 10 downloads per day, … Enforcement Rights executed as specified with technology and legal support

9. Jau-Wu Huang9 DRM in OMA OMA (Open Mobile Alliance) Formed in June 2002 By “ Open Mobile Architecture Initiative ” and “ WAP Forum ” Introduce/Promote open standards and specifications for mobile industry OMA DRM V2.0 3GPP move the MDRM(Mobile DRM) standardization to OMA

10. Jau-Wu Huang10 DRM in OMA(Cont1.) Right expression 4 key components Principal (user, compliance devices) Rights (copy, play, download, view, print, … ) Resource (the digital content) Condition (when, how, how much times, … ) Example Registered user 8043 can have 10 downloads from compliance device 132 starting from time xxx to time yyy

11. Jau-Wu Huang11 DRM in OMA(Cont2.) DRM package includes Rights Define how the device is allowed to render the content Copy, play, download … The usage right REL(Right Expression Language) A language to specify rights and their condition ODRL (Open Digital Right Language) Support an extensible language and data dictionary

12. Jau-Wu Huang12 DRM in OMA(Cont3.) Based on public key cryptography to enhance security support 3 download modes Forward Lock Allows single purchase and single delivery Content cannot forwarded to other devices Clear content WAP download Combined Delivery Clear content + rights WAP download Device conforms to rights Enable usage rules to be sent for the media object Add a RO(Right Object) to the DRM message

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15. Jau-Wu Huang15 DRM in OMA(Cont4.) Separate Delivery Protect higher-value media and enable right refreshment encrypted content WAP download Rights + key separately delivered Super distribution and separate channel Media is encrypted into DCF(DRM Content Format) Use symmetric encryption The rights hold the CEK(Content Encryption Key)

16. Jau-Wu Huang16 DRM in MPEG MPEG-4 IPMP Separate content stream (IPMP-ES) and associated rights (IPMP-Ds) Provides an interface between DRM-specific content and MPEG-4 terminal MPEG-21 IPMP An open interoperable framework for multimedia delivery and exchange Content encapsulation in Digital Item (regardless of format) REL standardized a way to associate rights with content The MPEG-21 REL is an XML-based language

17. Jau-Wu Huang17 DRM for Mobile Visual Content Multimedia portable device Small display size (screen) Power management Processor utilization Lower computational and memory capability Security issue Fulfill strict quality and bit rate requirement in real-time streaming application

18. Jau-Wu Huang18 Encryption Content encryption Block cipher technology DES (Data Encryption Standard) Selective encryption Only encrypt the compressed code stream header Only Intra frames could be encrypted in video

19. Jau-Wu Huang19 Watermarking Embedded information into digital content irremovably and invisibly Technology has its limitation Keep watermarking casting secret False alarm is more severe than missing Can still be a valuable component in a DRM system

20. Jau-Wu Huang20 Watermarking(Cont.) Fig. 2 shows that the use of watermarking to enhance DRM security MMS (Multimedia Message Service) content Stamp watermarks into the media object It ’ s only a stand-alone solution, not part of any OMA Spec.

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22. Jau-Wu Huang22 Watermarking of images and video Capacity Low-resolution image The carrier signal has lowered bandwidth A smaller capability for data hiding Content adaptation Watermark has to resist content adaptation It can consist of spatial subsampling of images/video to fit display size, color space reductions, or format conversion, …

23. Jau-Wu Huang23 Watermarking of images and video(Cont.) Computational complexity Watermark has to be simple to extract Security issue Further study of preventing abuse and security leakage strategy have to be carried out in open mobile platform

24. Jau-Wu Huang24 Conclusion Propose a system that integrate watermarking technology to stamp media content in MMS The limitations and requirements of the mobile visual content should be taken into consideration in mobile application