The Design And Implementation Of Multimedia Digital Rights Protection System Based On Mobile Terminals

With the rapid development of mobile Internet and popularity of portable terminals,the service of multimedia on mobile terminal equipment has more and more influence on people's life.An accompanying problem,digital rights protection also becomes more urgent than ever.Now the digital rights management(DRM)technology of mobile terminal equipment has attached extensive research.However,on one hand,most of these studies are only limited to the authorization control to the users' operations of the multimedia content resources,and lack fair and reliable mechanisms in the respect of tracing the source to piracy.On the other hand,in the research field of multimedia digital copyright protection based on technology of encryption and authorization,customer demands for combination or nesting of different types of multimedia resources are not taken into account,and the existing methods of sharing multimedia resources among multiple devices are not practical for mobile terminal equipment.In view of the above problems,on the basis of the predecessors' research work,a multimedia DRM system for mobile terminals is designed in the paper.With the using of the technology of encryption and authorization and the technology of tracing source to piracy,the digital copyright protection goes through the multimedia' s whole life cycle in the system.Meanwhile,the user friendly features are always important considerations in our system.The main work is as follows:(1)The interactive buyer-seller protocols based on watermarking technology are studied and analyzed,and on the basis of the predecessors'research work,we put forward a transaction protocol for multimedia digital products which is fit for mobile end customers.We use both the technology of encryption and authorization and the technology of tracing source to piracy,to make the digital copyright protection goes through the multimedia' s whole life cycle.Besides,the rights and interests of each participant in the commercialization of multimedia products are taken into account.(2)Combined with the core part of the protocol,a multimedia DRM system for mobile terminals is designed in the paper,which includes a series of processes,such as the digital content trading between mobile terminal users and distribution sales agencies,the protection and packaging processing for the multimedia products from the content issuer center,the authorization of the use of digital content on the mobile terminals,and so on.(3)With reference to the OMA DRM standard,a new digital content trading pattern is put forward in the system,which provides more flexible and fine-grained authorization way for customers.The new trading pattern gets rid of the restriction that the protection and packing objects for each transaction can only be the same format.It meets customer demands for combination or nesting of different types of multimedia resources.(4)A simple and practical method for sharing digital content among multiple mobile devices is designed and implemented in the system.We make improvements upon the Microsoft' s binding strategy for digital certificates and equipment.LRU(least recently used)elimination principle is used in the dynamic maintenance and updating of usersmobile devices list,which allows users to change their using mobile equipment and in the same time expensive processing cost in other terminal equipment is avoided.(5)The model of legal and security use of multimedia products on the mobile terminal equipment is designed and implemented,which is mainly about the local database design,the user authentication and the multimedia player.The player is developed to play the stream cipher without plain files being generated in the local storage.