Adaptive Video Encryption Algorithm, And In The Maritime Radio Monitoring System

This thesis analyzes the characteristics of video encryption used in military field and proposes the requests of the ocean wireless monitor system. Then it compares several video encryption algorithms which are commonly used. The algorithms'performances, including security, complexity, impacts on the compression and error resistance, have also been researched, especially for the DCT coefficients disordering algorithm. The frequency disordering algorithm and the Zig-Zag disordering algorithm are deeply researched with a practical instance. On these bases, this thesis proposes a special method named Adaptive and Integrative DCT Coefficients Disordering Encryption Algorithm(AIDCDEA). The frequency disordering algorithm and the Zig-Zag disordering algorithm have respective strongpoint and shortcomings. The AIDCDEA combines these two algorithms efficiently and reaches high performances in all aspects mentioned above. This thesis analyzes the main factors which affect the algorithm's performance and illustrates the principle by which some important parameters can be evaluated. Some key operations carried during the process haves been given feasible method, for example, the calculation of the position of the DCT coefficients divisions, and the disordering process with the given secret key. At the end of this thesis, the excellent performances of AIDCDEA have been studied in both theories and practice.