Research And Realization Of Digital Watermark Image And Multi-images Encryption Via Chaos Sequence

Multimedia information has been attacking by different kinds of means with the development of communication technology, and thus information safety has become a hot research topic now. Digital watermark has been an important protection for all kinds of information copyright. Thus, how to encrypt digital watermark effectively has been paid attention to researchers. Most of chaotic system encrypt single image, which result in a low effective for information. However, how to create high-dimensional chaotic system for producing multi-sequence to encrypt multi-images at the same time has also become a hot topic. Chaotic encryption technology has a wide application for its own particular advantages, such as a lot of keys, large key space and sensitivity of keys.Chaotic theory has been applied into the area of static digital images in paper. A matlab simulation system was built for encrypting the digital image via the popular image processing techniques (DWT, SVD) and chaotic technology. The matlab system includes five modules:digital watermark encryption, embeddeding, extracting, attracks and decryption. Some popular basic attracks were used for testing the safety of the system. We also realize the system via PC and ARM boards. To overcome the traditional limitations that a chaotic system can only encrypt or decrypt one image, this paper initiates a new approach to design 7-dimensional (7-D) discrete time chaotic controlled systems via some variables anti-control, which can achieve multipath drive-response synchronization, which are used for multi-images encryption and decryption.The details can be listed as following:(1) The history of chaos theory, digital watermark and embedded technology are introduced and we analyse the tenique of chaos theory combine to digital watermark.(2) A chaotic system is created in order to produce good performance chaotic sequence. We analyse its dynamics performance and test its random performance via NIST testing.(3) The matlab system is built for realizing the designation, including five modules: digital watermark encryption and decryption, embeddeding, extracting and physical attrack. Analyze the embedded system platform hardware and port the Linux operating system to the experimental platform. Specifically, bootloader, Linux Kernel, root file system and some application programs are included. Lastly, an embedded digital watermark communication system is designed via Mini2440 ARM boards.(4) A systematic methodology is developed for multi-images encryption and decryption and field programmable gate array (FPGA) embedded implementation by using single discrete time chaotic system. A generalized design principle and the corresponding implementation steps are also given. Based on the FPGA embedded hardware system working platform with XUP Virtex-Ⅱ type, a chaotic secure communication system for three digital color images encryption and decryption by using a 7D discrete time chaotic system is designed, and the related system design and hardware implementation results are demonstrated, with the related mathematical problems analyzed.