Research On Selective Encryption Algorithm Based On HEVC

Video,as an information carrier,can transmit information intuitively and efficiently,and has a large information capacity.It has been widely used in the digital information age.At the same time,due to the advent of the Internet era,the rapid popularization of wireless WiFi and mobile devices,network environment security is facing severe challenges,the leakage of video information is common.On the other hand,people are becoming conscious of information privacy and information security at all levels of society,so it is imperative to protect video information security.Therefore,video encryption has been paid more and more attention.Video itself has a large amount of information,complex data structure and high real-time requirement,so the traditional method of encrypting data is no longer applicable.It is necessary to design specific encryption algorithm according to video coding standards.In this paper,based on the latest international video coding standard-High Efficiency Video Coding(HEVC),some syntax elements of HEVC coding are selectively encrypted through a detailed study of entropy coding.The main contents of this paper are as follows:Firstly,the Context-based Adaptive Binary Arithmetic Coding(CABAC)module of HEVC is studied in detail.Through the analysis of HEVC grammar elements,the syntax elements suitable for encryption are found,and a selective encryption algorithm based on HEVC is proposed.In order to ensure the compatibility of video streams,the syntax elements related to video content should be encrypted.In CABAC,the syntax elements using bypass coding mode after binarization are suitable for encryption because of their standard format and no context model.Five binarization methods are analyzed in detail in this paper.Finally,six grammar elements are selected and encrypted by Rivest Cipher 6-Cipher FeedBack(RC6-CFB)algorithm.The experimental results meet the requirements of compatibility,security,compression rate invariance and real-time performance.Secondly,in order to ensure the compression performance of HEVC,the existing encryption algorithms encrypt the grammar elements using bypass coding,which have a narrow range of choices,or encrypt other grammar elements while reducing the encoding performance of HEVC.To solve the above problems,a selective joint encryption algorithm based on secure Binary Arithmetic Coding(BAC)is proposed,which encrypts the binary arithmetic encoding process in the regular encoding mode.On the basis of encrypting by-pass coding syntax elements,three syntax elements are selected as encrypting objects of secure BAC.The experimental results show that the encrypting effect is good,and no additional bit rate is added.The computational complexity is low,which guarantees real-time performance.Finally,for application scenarios that do not require the highest security,the encryption algorithm should improve the encryption efficiency as much as possible on the premise of ensuring certain security.In this paper,each syntax element is encrypted according to the sensitivity of the codeword,and the encrypted range of the syntax element is reduced.Five syntax elements are selected for joint encryption,and a joint encryption algorithm based on the sensitivity of the codeword is proposed.The experimental results show that the algorithm can further shorten the encrypting time and improve the encrypting efficiency on the premise of satisfying the compatibility,security and invariance of compression rate.