Research On Selective Encryption Schemes Based On H.264/AVC Entropy Coding Using Chaos Theories

In recent years,with the rapid development of network technology,applications and services regarding video clips as the information carrier get people's more and more attention and love.As a result,there is a risk that multimedia information may be eavesdropped in its transmission process in public network and video encryption is an effective method to prevent information being stolen.However,using existing password standard to encrypt complete video stream is generally unnecessary and undesirable,because the amount of calculation will not only increase,but also it will destroy the structure of the video,making it impossible to make some interactive operation on video.In order to maintain low-complexity and video's structure,some scholars propose the selective encryption method which will encrypt some important information.In order to meet video's instantaneity,this paper designs a PRNG(Pseudo-Random Number Generator)base on the Logistic chaos dynamic equation to generate pseudo-random sequence.In pseudo-random sequence generation process,there are two key to generate PRNG so that the generated PRNG could have higher security and could fully meet video's instantaneity.This paper proposes two methods which entropy video on the basis of the entropy coding.For different grades,this paper puts forward two encryption algorithms respectively based on CAVLC(Context-based Adaptive Variable Length Coding)and CABAC(context-based binary arithmetic coding).Experimental results show that in encryption algorithm based on CAVLC,time consumption in the process of encoding is almost equal to the normal encoding process,while video spatial expansion after encoding is O.In encryption algorithm based on CABAC,time consumption in the process of encoding is about 0.4%more,while video spatial expansion after encoding is about 2%.It fully meets the requirement of instantaneity.Besides,the spatial expansion is low and the bandwidth requirement is also reduced,maintaining the H.264 video structure.What's more,compared with the decrypted video images after the normal H.264 decoding process,the decrypted video images are completely undamaged.