Research On Digital Video Encryption And Privacy Protection Algorithm Based On H.264

With the rapid development of information technology, video has been widelyused in politics, military, business, education and other fields. As H.264is a videocoding standard of the next generation, it has played an important role in real-timevideo communication, network streaming media and various fields due to its superiorcompression performance and excellent network performance. However, its securityproblems have been paid much attention in recent years.In order to cope with the potential threats, a variety of methods includingencryption/decryption, digital watermarking and access control policies are putforward. Since video has a large volume of data, high real-time requirements andother characteristics, it is difficult for them to be applied in the protection of video;meanwhile, most of existed video encryption methods are proposed for MPEGstandard. Therefore, it is desirable to design video encryption algorithm which canmeet different application needs for H.264. The main work of the thesis includes:Some basic knowledge about H.264, video encryption and privacy protectiontechnologies are first introduced, and then the state-of-art are presented. After that,the limitations of the existed methods are analyzed.A selective video encryption scheme based on chaotic is proposed. Apseudorandom sequence generator is constructed by taking full usage of theunpredictability and other characteristics of chaos. Some key data such as intraprediction mode, motion vector difference and residual coefficient of H.264areencrypted by the pseudorandom sequence. Experimental results and analysis indicatethat the scheme has a good encryption effect, a low computational complexity, littleimpact on compression performance and format-compatibility.Aiming at the privacy problem in the video surveillance system, a privacyprotection scheme based on ROI (Region of Interest) and chaos is proposed. The ROIis first detected, and then the FMO (Flexible Macroblock Ordering) is used to map theROI to different groups for encryption. Experimental results and analysis show thatthe proposed scheme can protect the private information successfully. Moreover, ithas a good tradeoff between security and efficiency, and can meet the needs ofreal-time applications.On the basis of the above algorithms, an encryption and privacy protection system for H.264video is designed and implemented. The system integrated H.264codec, encryption/decryption, and playback function, the interface is friendfrifrily, italso provides a platform for the further research on video encryption algorithm.The encryption and privacy protection methods proposed above can effectivelyprotect the content of H.264video, and have potential to be applied in occasions suchas CCTV.