Research On Video Chaotic Encryption Technology And Implementation Of Android Platform

Nowadays,everyone's life is inseparable from the mobile phone,and with the rapid development of 5G technology,video gradually becomes the main way to social communication and record life.However,due to the open source feature of Android and the openness and sharing of network transmission,there is a widely concern about the security of video storage and transmission on Android phones.Video is characterized by large data volume,strong correlation between adjacent pixels,and high redundancy in time and space.Therefore text encryption standards like Data Encryption Standard(DES)and Advanced Encryption Standard(AES)are no longer applicable.In recent years,chaos theory has been developed and some inherent characteristics of chaotic systems have been found to be extremely similar to those of encryption systems.After that,cryptography researchers start applying chaos theory to video encryption system.In this paper,two video encryption schemes based on chaos theory are proposed and experimentally tested,and finally the selective encryption scheme is implemented in Android platform.The first encryption algorithm is to encrypt a frame image before performing H.264 compression coding.In the encryption algorithm,a combination of a four-dimensional Lorenz chaos system and DNA coding is proposed to encrypt image.The permutation process based on the DNA coding level not only changes the position of the pixel in image,but also the value of the pixel in permutation stage,which enhances the security of the encryption system.At the same time,the use of random DNA encoding rules for encoding the plain-text pixel values greatly increases the randomness of the encryption system compared to a deterministic DNA encoding rule.In addition,the involvement of the DNA encoding characteristics of the plain-text(PPDC)in the permutation algorithm makes the key stream used for scrambling relevant not only to the key but also to the image to be encrypted,improving the plain-text sensitivity of the encryption algorithm.Therefore,the encryption system is secure and reliable from all aspects.The second encryption scheme is to encrypt syntax elements in the process of H.264 compression coding.Not all syntax elements can be encrypted,some of them would destroy the video format,and some of them would seriously affect the encryption speed or cause problems such as over-expansion of the encrypted video data.Therefore,in order to find out the encryptable syntax element and analyze the experimental results,a detailed analysis of syntax elements is necessary.The paper proposes an encryption algorithm for six syntactic elements in single or combined form.There are prediction mode(luminance,chrominance),quantization parameter offset value,motion vector difference,DC component of discrete cosine transform,AC component symbols and trailing coefficient symbols.The first chaos-based encryption algorithm is improved according to the different value ranges of syntax elements,and the coding schemes of 4-code,2-code and 1-code are proposed.Finally,by analyzing the open source frameworks of X264 and JM codecs,the syntax elements encrypted are found,afterwards the cryptographic algorithm are embedded into the codec process of H.264 to realize the selective encryption scheme for syntax elements,then ultimately transplant the selective encryption scheme to the Android platform for implementation.