Research On Content Security Algorithms Of Typical Medias Represented By 2D Vector Graph Model

In this age of universal electronic connectivity, of viruses and hackers, of electronic eavesdropping and electronic fraud, there is indeed no time at which security does not matter. Content security techniques for multimedia, for example cryptography and information hiding techniques, have recently become important in a number of application areas. 2D Vector maps and PDF documents, which are represented by 2D vector graph model, have become more and more prevalent, and applications of these medias have been increasing rapidly. But content security algorithms for 2D Vector maps and PDF documents draw little attention within the security community.Aim at the research of Content security algorithms for medias represented by 2D vector graph model, and to meet the need of a security application project, we have built"A Secure Steganographic System Hiding Data in a kind of PDF Texts", and have presented"A Practical Map Encryption Algorithm Based on Chaos System Under a Network Circumstance"and"An Efficient Lossless Compression Algorithm for a kind of Two-Dimension Vector Maps". We also have given"The Feasibility Analysis of Normalized-Correlation-Based Vector Maps Watermarking Detection Algorithm and the Improved Watermarking Algorithm", and have proposed"A New Geometric Transformation Robust and Practical Embedding Scheme for Watermarking 2D Vector Maps in the Graph Spectral Domain".The major works of this dissertation are as follows:1. A Secure Steganographic System Hiding Data in a kind of PDF Texts We present a novel steganographic technique through hiding data in a kind of PDF texts. we first point out that there are secret channels in a kind of PDF English texts, which individually position each character and produced from documents which make the text be justified to occupy the full line width. In succession, we present the novel steganographic system. In the system, several strategies are applied to improve security: we use some redundancy to compensate security; two chaotic maps are constituted to meet the Kerckhoffs principle and adjust statistical attacks; and the secure hash algorithm is applied to supply integrity service and blind extracting service. In addition, we define the rate of embedding capacity.2. A Practical Map Encryption Algorithm Based on Chaos System Under a Network...