Research On Video Stream Encryption Algorithm Based On Sequence Ciphe

With the frequent occurrence of network security events,people pay more attention to privacy security.In particular,the demand for video content protection in real-time areas such as computer vision,security monitoring and military confidentiality is also increasing.For real-time application scenarios,it is very important to achieve efficient encryption while guaranteeing the quality of video transmission.This paper studies the feasibility of applying ZUC,a sequence cipher algorithm in the field of communication,to video stream encryption in software environment.In this paper,two video stream encryption methods based on quantized DCT coefficients encryption and encoding slice load encryption are proposed in H.264 macroblock encoding phase and video stream pushing phase,respectively.Based on these two encryption methods,a real-time video stream encryption system is designed and implemented,and the security and applicability of the encryption method are verified under this system.The main work of this paper is as follows:1.By explaining the development of video encoding and transmission technology and several common video stream encryption strategies,this paper analyses the applicability and limitations of various encryption algorithms in the video encoding process,and designs and counts the number of macroblocks in GOP and the number of DCT calls,which verifies the theoretical feasibility of the ZUC sequence cipher algorithm for video stream encoding.Therefore,two methods of encrypting based on ZUC and encrypting after encoding are presented in this paper.The former encrypts the predicted residual through DCT transformation and quantified encoding coefficients,while the latter encrypts the load of VLC layer slices in the stream by analyzing NAL.2.Based on the above two encryption methods,a real-time video stream encryption system with security features is designed and implemented in this paper.By introducing the ZUC sequence generator into the source code of the x264 codec,the encrypted content is protected.In addition,NAL analysis is implemented through the open source library of h264 bitstream,encrypting the load of encoding slices,so as to protect the video content without destroying the encoding encapsulation format.In addition,the system uses JWT and SM2 public key cryptography algorithm to implement the security authentication and key exchange protocol,and uses ffmpeg and nginx to convert the format of real-time image frames and multiple forwarding of real-time video streams.3.Based on this system,experiments are designed to verify the applicability of the ZUC sequence cipher algorithm to encoding.The experimental results show that the encryption algorithm can achieve perceptual security and ciphertext security while encrypting,and the video fluid volume of encrypted encoding expands below 10%.The correlation coefficient of adjacent pixels in three directions of encrypted image frame is between 0.3 and 0.6,which has some anti-attack characteristics,and the quality of decrypted image is not affected.The two encryption schemes proposed in this paper have good practical prospects.The pre-encoding encryption algorithm can be applied to customized codec scenarios and has good encryption characteristics.The bitstream-oriented NAL parsing encryption algorithm can be applied to all kinds of video stream encryption services more generally and has good NAL layer format compatibility.