The Research On The Algorithms Of Image Encryption And Watermarking Based On The Itineraries Of Tent Map And Baker Map

With the rapid development of computer network communication technology, the protection of information security has become a common concern. The information hiding in the digital image has also become one of the research hot spots, its main measures include:digital image scrambling, digital image sub-storage technology, digital image hiding technology and digital watermarking technology.Based on the researches on the status of digital watermarking at home and abroad, the watermarking preprocessing is mainly studied in this thesis combined the three-dimensional Hilbert curve and the theory of symbolic dynamical system about itinerary. The main work in this thesis is as follows:(1) The background and significance of digital image processing are shown briefly. The technology and research status of image watermarking are introduced, meanwhile the sources of the topic in this thesis are analyzed.(2) The scrambling and encryption algorithms in the preprocessing of watermarking are studied as follows. The scrambling method based on the three-dimensional Hilbert curve is proposed; simulation verifies that this method is superior to the method based on the two-dimensional Hilbert curve in terms of scrambling degree and robustness. In addition, the scrambling method based on the itinerary of tent map and the encryption algorithm based on the itinerary of Baker map are proposed respectively combined the relation between itinerary in symbolic dynamical system and the K-nary. Meanwhile the effectiveness of the two algorithms is verified in the simulations.(3)Based on the study on preprocessing above, the watermarking algorithms on the spatial and wavelet domain are proposed respectively. The transparency and robustness are also tested.