Research On Mobile DRM Based On Digital Watermarking And Encryption Technology

Along with the rapid development of mobile Internet technology and the issuance of 3G operating licenses in China, We formally entered the 3G era. Users can access the Internet anywhere to browse their interesting digital contents. Almost all copyright works can provide for users after digitalization. However, due to the openness of the network and the simplicity of copying, all kinds of infringement and piracy are crazy rampant. Intellectual property protection and copyright authentication of digital content have become increasingly prominent, even a very urgent issue in the digital world.Based on the study of the digital rights management and digital watermarking technology, the paper put forward a new mobile DRM system model. There are six key technology involved in this model, that is digital encryption, digital signature, digital watermarking, permissions description and transfer, XML language, and mobile agents. Digital watermarking as the most powerful complement to traditional DRM system, it provide more comprehensive protection of copyright by authenticity of identification, use of control and tracking.The paper designed a new mobile DRM system combining the theory of OMA DRM 2.0 with digital watermarking, analyzed the system's content protection mechanisms and security, solved the existing system deficiency, gave the realization in mobile terminal, described the responsibilities of the entities and information flow in the DRM controller, and designed the interface between terminal and server.Further researched on digital watermarking algorithm, introduced the attack types and characteristics of algorithm, analyzed the typical watermarking algorithm for copyright protection, and presented a simulation test for each representative algorithm in spatial domain and transform domain. Experimental results show that algorithms in spatial domain have real-time property, smaller computational complexity and larger capacity, but poor robustness that can not resist common signal processing attacks. While robustness of algorithm in transform domain is much better than in space. Quantization-based watermarking algorithm can be detected blindly, but more sensitive to noise.In order to improve the performance of DM, this paper proposes a watermarking algorithm that is a combination of JPEG quantization table and Watson model for the spread transform dither modulation. The simulation results show that the algorithm can be applied to Mobile DRM system for copyright management and protection because it has stronger robustness that it can resist common attacks for digital watermark and alleviate the sensitivity effectively to noise for quantization watermarking algorithm. Finally, put forward an application solution using robust watermarking and fragile watermarking to provide dual protection for digital content in the mobile DRM system.