基于自同步混沌流密码的HEVC视频ROI加密算法

HEVC Video ROI Encryption Algorithm Based on Self-synchronized Chaotic Stream Cipher

在公共网络上广泛传播的视频不可避免地包含有隐私信息。为此很多针对视频的加密方案相继提出。文章针对HEVC视频感兴趣区域(ROI)提出一种自同步混沌流密码加密算法,以人脸所在区域作为感兴趣区域为例,实现对HEVC视频隐私区域的保护。首先,根据动力系统反控制原理,构建出无简并三维离散超混沌系统。在此基础上,提出一种自同步混沌流密码系统。然后,对HEVC视频ROI实现加密,具体如下。对于HEVC视频序列中的I帧,检测人脸所在区域并作为ROI;对于P帧,则利用视频流中压缩域信息追踪ROI。并将ROI信息转化为Tiles索引。利用自同步混沌流密码系统生成的伪随机序列对Tiles索引以及Tile内的语法元素MVD符号位、MVD值和QTC符号位进行加密。解码端的解密算法也同时详细给出。同时,借助补充增强信息(SEI)实现编解码端对ROI信息的同步。实验结果验证了所提方案的有效性。最后,对所提方法的性能和安全性进行了分析,并对所提方法的嵌入对编码器所带来的影响进行了讨论。

Videos that spread widely on public networks contain private information inevitably.For this reason,many selective encryption schemes for videos have been proposed.In this paper,a self-synchronizing chaotic streamcipher algorithmfor ROI of HEVC video is proposed.By taking the face regions as ROI as an example,the privacy area of HEVC video can be protected.According to the anticontrol principle of dynamic systems,a no-degenerate 3D discrete hyperchaotic systemis firstly constructed.On this basis,a self-synchronizing chaotic stream cryptosystem is proposed.Then,the encryption for HEVC video ROI is implemented as follows.For the I frame in the video sequence,the area where the face is located is detected and used as an ROI,and for the P frame,the compressed domain information of the video stream is used to track the ROI.The ROI information is then converted into Tiles index.The Tiles index and the syntax elements MVD symbol bit,MVD value and QTC symbol bit in the Tile are encrypted using the pseudo-randomsequence generated by the self-synchronizing chaotic streamcryptosystem.The decryption algorithm on the decoding end is also given in detail.Meanwhile the ROI information is synchronized by the codec end with the help of supplementary reinforcement information(SEI).Experimental results verify the effectiveness of the proposed scheme.Finally,the performance and security of the proposed method are analyzed.The impact of the embedding of the proposed method on the encoder end is also discussed.