Study And Simulation Of Encryption Scheme In Digital TV Terrestrial Broadcasting System

With the fast development of multimedia, the network and the communication technology, digital television, regarded as the most popular dissemination media, has widely applied in the economy, the education, the politics, the military affairs and so on, at the same time, the multimedia information security problem receives more and more attention. The high BER (Bit Errot Rate) in the wireless transmission system gives a serious impact on the secret transmiision of multimedia information. It is in conformity with the information security request of the nation and the army to study on the secret transmission of digital television in wireless system.As the first part, the digital television and its standard specification as well as the current situations of the encryption technology of digital television system have been introduced, the problems of transmission of secret digital television by the ground broadcast wireless system have also been raised. Then the format of MPEG-2 provided by the DVB standard is introduced, a deep study of the encryption technology of different code format of each layer has been maked too, at the end of the second part, a summary of the request in the ground broadcast system encryption is provided. In the third part, according to the characteristic of the source, an audio encryption scheme based on the scrabling and a video encryption scheme based on the error control are designed, with the analyzing of simulation results, it is indicated that when transmitt the audio or video information separately, a better efficiency will be obtained. In the next part, a policy used to update and transmission of the key that fitted with the wireless system has been proposed, the compartion results between the policy and the key transmission scheme in CAS prove that this policy have both the well security and real-time quality. Finally, the transmission process of sound/video and keys is simulated in System View end-to-end. Simulation, the simulation result indicated, the encryption scheme has characteristic in safe and the real-time which suitable for secrity transmission in DTTB system, it also can reduce error and error diffuse effectively.