Research On Key Techniques Of Secret Level Marking System For Vector Graphics

With the development of computer science and networks, the security of digitalinformation has become a hot topic in information area. According to the idea of CSI(Computer Security Institute), about 80 percent of the information leaking cases werecaused by the insiders. In order to improve the security of the digital information, weshould build the management system to control the access of different people to differentfiles. Vector graphic is one of the most important carriers for commercial and militarysecrets. So, the researches on the secret identification techniques for vector graphics areof great importance.In this thesis, we first surveyed and analyzed the detailed provisions for secret clas-sification and identification in China. According to the requirement of the detailed pro-visions, we designed the framework of secret level marking system for digital vectorgraphics, with the consideration on the characterization of vector graphics. The systemcontains three modules, including the module for secret level marking, the module for theprotection of the classified files and the module of the role-based access control. Basedon the goal of the system, we have made the following contributions:Firstly, we have designed the secret level marking scheme for digital vector graphicsthat satisfying the standard requirement of the detailed provisions. In this scheme, weused the techniques of watermarking and treated the secret information as watermarks forvector graphics, with which to implement the secret level marking related functions suchas secret generation, embedding, updating, deleting and releasing.Secondly, we surveyed the current digital watermarking algorithms on vector graph-ics and proposed a robust digital watermarking algorithm for vector graphics. This algo-rithm takes advantages of the location of digital numbers in vector graphics representa-tion, and owns the advantages of high capacity, transparency and great robustness.Thirdly, we proposed a role-based access scheme for the classified vector schemewith the help of ePass 2000. By using the ePass 2000 as the tools to classify the role ofthe users, we designed and applied the access strategy of the classified vector graphics toprevent unauthenticated accessing.Taking advantages of the technologies of ObjectARX as the developing tools of AutoCAD, we implemented the proposed digital vector graphic protection system. Thetested results show that the system implemented the required functions and goals. Theformat of the secret level marks and the process of marking satisfy the detailed provisions,and the system works efficiently with high security considerations.