Digital Watermarking And Multimedia Information Security

With the rapidly development of Internet, it is more and more easy to get some digital multi-media information. However, it also causes some problems, such as copyright protection and information encryption, which become more urgency day by day. Therefore, many scholars are attracted by the multi-media information security problem.In this thesis, the author studies one of its branch-digital watermarking of images. First, some basic conceptions, specialties and application domains of it are introduced. Second, the pretreatment of digital watermarking data is discussed one by one, and their shortcomings and excellence are also pointed out. Third, many kinds of embedding technology of digital watermarking data is analyzed carefully, and presented some test datum and analysis of the tracing copyright watermark. Based on upon research, this paper proposes two algorisms; watermarking algorism of reversible wavelet transformation, JPEG2000 image encryption algorism of chaos theory. Author implemented these algorisms and analyzed the results of performances. The experimental results demonstrate that the former algorism has great capability to resist contrast attack and brightness attack while the second algorism is much more robust to resist compression attack. But in the research of this thesis, we discovered that the performance of these two algorism to resist noise interfere is not good enough, they need to be improve in future work. In the last chapter, work of the thesis is summarized, and the further research directions are being discussed.