【作者】 胡忠彪；

【导师】 闫保中；

【作者基本信息】 哈尔滨工程大学 ， 导航、制导与控制， 2011， 硕士

【摘要】 随着移动互联网技术的高速发展及3G运营牌照的发放,我国正式步入了3G时代。用户随时随地都可以接入互联网,访问感兴趣的多媒体数字内容。几乎所有的版权作品数字化以后都能通过网络提供给用户。然而,由于网络环境的开放性以及数字内容拷贝的简易性,各种侵权行为及盗版作品疯狂泛滥,数字内容的知识产权保护和版权管理等问题变得越发突出,并已成为数字世界中一个非常紧迫的议题。本文首先对数字版权管理(Digital Rights Management,DRM)及数字水印技术的发展现状进行研究,在此基础上提出一种改进的移动DRM系统模型。该模型涉及的关键技术有数字加密、数字签名、数字水印、数字权限描述及权限转移机制以及移动代理等。数字水印作为传统DRM系统最有力的补充,提供真假鉴定、权限控制、使用跟踪以及版权验证等功能,使版权保护更加全面,符合未来发展趋势。本文将基于开放移动联盟(Open Mobile Alliance,OMA)2.0标准的DRM系统与数字水印等信息安全技术有效结合,设计了一种新的移动DRM系统方案。文中分析了该方案的内容保护机制及系统安全性,解决了现有移动DRM系统存在的不足,并设计了DRM在移动终端上的实现方法,阐述了移动终端DRM控制器中各实体的职责和信息流,以及终端与服务器之间的接口协议等。深入研究了数字水印技术,分析了一般水印算法的特性及水印攻击类型,着重讨论了用于版权保护的典型水印算法,并从空间域和变换域中各选择了一种代表性算法进行具体分析及仿真测试。实验结果表明,空域算法实时性较强,计算复杂度低,且水印容量较大,缺点是鲁棒性很差,无法抵抗常见的信号处理攻击。而变换域算法鲁棒性要比空域算法好得多,且基于量化的水印算法还可以实现盲检测,但对噪声较敏感。通过对抖动调制水印算法进行改进,提出了结合JPEG量化表和Watson模型的扩展变换抖动调制水印算法。对该算法进行鲁棒性测试,并与相关算法进行比较,测试结果显示改进的水印算法综合性能最佳,可抵抗常见信号处理(如几何变换、滤波以及JPEG压缩等)的攻击,同时缓解了量化水印算法对噪声的敏感程度,可应用于移动DRM系统中,为数字媒体提供版权管理与保护。最后提出了一种在移动DRM系统中同时应用鲁棒水印和脆弱水印为数字内容提供双重保护的方案。更多还原

【Abstract】 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.更多还原