面向多媒体加密的复变量混沌伪随机序列研究

Chaos-based encryption technique is cost-effective and time-efficient. So it is very fit for protecting the security of the multimedia files with massive data. One of the key techniques is generation and analysis of pseudorandom sequence. This project studies the generation of pseudorandom sequence with chaos and the encryption of multimedia data. Existing methods generate pseudorandom sequence with real variable chaos. As a result, the theory basis is weak and the performance is degenerated after discretization. Aiming at the two issues, this project studies complex variable chaos based pseudorandom sequence generation and multimedia data encryption. 1) the research of chaos-based pseudorandom sequence is extended from the real number field to complex number field. A complex number-based chaos model is constructed and proved with strict mathematics reasoning. 2) Aiming at the characteristics of complex number-based chaos model, high-efficiency pseudorandom sequence generating methods fit for complex number-based chaotic sequence are researched. 3) complex number-based chaotic pseudorandom sequence is applied to protect the security of multimedia data such as images and videos. The secure and high-efficiency encryption algorithms are proposed. This project will provide a new idea for the theory study of chaos based encryption technique. It will also provide a feasible security protection method for high resolution images, remote sensing images and video data in military affairs and spaceflight fields and multimedia data in network communication.

基于混沌的密码技术，实现效率高而花费代价小，非常适合保护数据量大的多媒体文件，其中一个关键技术是伪随机序列产生及分析。本项目研究利用混沌技术产生伪随机序列并加密多媒体数据。现有方法利用实变量混沌技术产生伪随机序列，理论基础薄弱，且容易导致离散化后性能退化等问题。本项目针对这两个问题，研究基于复变量的混沌伪随机序列产生及多媒体数据加密：1）将混沌多媒体数据加密的研究从实数域扩展到复数域，用严格的数学推理构造和证明复变量混沌模型；2）针对复变量混沌模型的特征，构造适合复变量混沌序列的高效伪随机序列产生方法；3）利用复变量混沌伪随机序列加密图像和视频等多媒体数据，实现安全、高效的加密算法。本项目的研究，为混沌密码技术的理论研究提供一种新的思路，也为军事、航天等领域中高分、遥感图像和视频数据及网络通信中的多媒体数据提供切实可行的安全保护方法。

本项目研究了基于复变量的混沌模型，产生伪随机序列并加密多媒体数据。构造并优化了性能良好的复数混沌模型，利用严格的数学推理证明模型的混沌性，给出其参数特征，并利用仿真实验对模型进行验证。提出并优化了适用于复数的混沌序列离散化方法，并将伪随机序列作为密钥，提出了多个加密算法，保护多媒体文件的安全性。理论分析和实验测试表明：与现有混沌模型相比，提出的模型在Lyapunov指数以及序列复杂性方面具有较大优势，其所产生的伪随机序列具有长周期、高复杂性和随机性等特征；构建的适合图像及视频等海量数据的多媒体文件保护算法具有较高的安全性和加密速度，能够较好的保护多媒体数据。本项目的研究，为军事、航天等领域中高分、遥感图像和视频数据及网络通信中的多媒体数据提供切实可行的安全保护方法。