The Research Of Selective Video Encryption Based On H.264/AVC And HEVC

With the proliferation of video applications over the Internet,such as pay-TV and Video-on-Demand(VoD)service,the privacy and copyright protection of video content are becoming critical issues.In order to ensure that the videos will not be illegally copied in transmission and storage,video encryption emerged.Since video encryption should comprehensively meet with real-time requirements,high security,compression invariance and other features,in designing the encryption algorithm these features should be taken into consideration.As the current most widely used video compression standard,H.264 and HEVC have good network adaptability and excellent compression performance.This paper summarizes the structure and key technologies of H.264/AVC and HEVC encoder.On this basis,the paper combines the features of the two video coding standards to research corresponding video encryption technology.Specifically,the main contributions of this paper are as follows:Firstly,a perceptual encryption algorithm for H.264/AVC videos using two new scan orders is proposed.By analyzing the energy distribution of DCT coefficients encoded by H.264/AVC,two new scanning schemes are presented.It is theoretically proved that they have similar characteristics of zig-zag scanning,and their influences on the efficiency of entropy coding are very limited.By combining them with other two existing scanning schemes,an improved perceptual video encryption algorithm is proposed for H.264/AVC in this paper.It randomly selects one scanning mode from four modes by encryption keys,and incorporates the sign bit-flipping of DC coefficients to further improve the encryption results.Experimental results show that the proposed approach have the advantages of less bitrate increase and lower computational costs.Compared with the existing encryption schemes by randomized zig-zag scanning,the proposed approach is more flexible and has bigger search space,and thus has stronger security and better encryption results.Secondly,based on the prediction mechanism of HEVC,an efficient encryption algorithm is proposed.In this paper,the motion reference ratio(MRR)of CUs is used to describe the inter-frame dependency,then statistics is applied to the MRRs of CUs,and CUs are selected to be encrypted based on the statistical results.At the bitstream layer of CUs,sensitive information including the DCT coefficient signs,motionvectors and Merge_idxs are encypted.Experimental results show that the proposed approach has low computational cost and good scrambling effect.