结合超混沌系统和Logistic映射的视频图像加密算法

对视频图像使用传统的单幅图像加密算法，容易出现算法耗时长、效率低等问题。为提高视频图像加密效率，通过使用细胞神经网络（CNN）超混沌系统和Logistic混沌映射，提出一种单帧逐一加密和多帧组合加密相结合的算法。根据视频帧使用SHA-256生成Logistic初值，经过Logistic映射迭代得到Logistic混沌序列，利用生成的混沌序列对视频帧逐帧扩散。将视频帧以二进制的形式组合成一个矩阵，把根据组合矩阵产生的初值代入CNN超混沌系统，利用得到的混沌序列对组合矩阵进行置乱，视频所有帧各像素点扩散、置乱一步完成，从而缩短加密时间。在此基础上，将组合矩阵重新分解为单帧图像，得到最终加密的视频图像。实验结果表明，在算法中使用高维超混沌系统安全性更高，能够有效缩短加密视频图像的耗时，且能抵抗统计攻击、差分攻击和暴力攻击，具有较好的安全性。

Encryption Algorithm of Video Images Combining Hyper-Chaotic System and Logistic Mapping

Using the traditional single image encryption algorithm for video images is time-consuming and inefficient. To improve the efficiency of video image encryption, combined with the Cellular Neural Network(CNN) hyper-chaotic system and Logistic chaos mapping, an algorithm combining single frame encryption one by one and multi-frame combination encryption is proposed.According to the video frame, SHA-256 generates the initial value of logistic, and the logistic chaotic sequence is obtained through Logistic mapping iteration.The generated chaotic sequence diffuses the video frame by frame.The video frames are combined into a matrix in binary form, and the initial value generated by using the hash function according to the combination matrix is substituted into CNN hyper-chaotic system.The obtained chaotic sequence scrambles the combination matrix, and the diffusion and scrambling of each pixel of all video frames are completed in one step to shorten the encryption time.Simultaneously, the combination matrix is re-decomposed into a single frame image to obtain the final encrypted video image.Experiments show that using a high-dimensional hyper-chaotic system in the algorithm has higher security, effectively shortens the time spent encrypting video images, and can resist statistical attacks, differential attacks, and violent attacks.