云环境下加密域可逆信息隐藏的新方法研究

Reversible data hiding in encrypted domain is a novel data hiding technique that can preserve the privacy of multimedia of users in cloud computing. However, some defects still remain in reversible data hiding in encrypted domain: the basic model of reversible data hidng in ecnrypted domain still to be improved; most existing methods cannot be applied to encrypted audio or videos; the embedding rate and the probability for lossless recovering the multimedia in reversible data hiding in encrypted domain are relatively low. To solve the above mentioned problems, multimedia signal processing algorithms including data sharing for encrypted multimedia, compress algorithm for encrypted multimedia with high compression rate and reversible data hiding in encrypted images with high embedding rate and reversibility are investigated in this project. First of all, typical methods of reversible data hiding in encrypted domain are studied. Then, some improved reversible data hiding methods for encrypted multimedia are proposed based on homomorphic encryption, visual cryptography, conventional data compression, entropy coding, matrix embedding. These proposed methods are further improved according to the analysis and extensive experimental results. And finally, a set of reversible data hiding algorithms in encrypted domain is demonstrated for cloud computing. Meanwhile, five or more research papers and one patents are formed in this project to further improve the technique of reversible data hiding in encrypted domain.

加密域可逆信息隐藏技术是为保障云计算环境下用户多媒体数据隐私性、安全性而提出的新型数据隐藏方法。然而，加密域可逆信息隐藏的研究处于初级阶段，仍存在以下的问题：真正融合密码学与信息隐藏技术的理论模型尚未成熟；大多算法仅能处理加密图像，无法处理加密音、视频；已有算法的嵌入率不高、可逆性不强，部分算法存在安全隐患。为解决以上问题，项目组计划从分析已有的加密域可逆信息隐藏方法入手，结合同态加密、视觉密码、传统的图像/视频压缩理论，熵编码和矩阵编码等理论，研究基于同态加密、视觉密码的加密域可逆信息隐藏的理论模型，通过实现通用数据嵌入、统一表示模型的方法来完成多种加密媒体的可逆信息嵌入，并从预测编码、内容盲压缩等手段提升算法的性能。到本项目结束时，希望能形成5篇以上的高水平论文及1项国家发明专利，同时，通过本项目的研究，进一步推动加密域可逆信息隐藏的发展。

加密域可逆信息隐藏技术是为保障云计算环境下用户多媒体数据隐私性、安全性而提出的新型数据隐藏、标记方法。针对加密域可逆信息隐藏中存在的一系列问题，项目组提出了多种融合同态加密、秘密分享的加密域可逆信息隐藏算法，从理论上对所提出的算法进行了推导及验证，并进行了大量的数据实验及对比。所提出的算法能进一步夯实融合密码学技术和信息隐藏技术的理论基础。并在一定程度上，有效提升了加密域可逆信息隐藏算法的主要性能指示。截止到本项目结题时，课题组已在国际知名计算机期刊(SCI索引)上发表学术论文9篇。此外，所提出的算法已形成一个初步的可适用于云环境的加密域可逆信息隐藏平台，为加密域可逆信息隐藏的发展做出贡献。