To solve the large delay problem of video coding by using the chaotic encryption ,a fast security encryption algorithm for H .264／AVC video is proposed .First ,a key generation scheme is designed .Four groups of chaotic sequences are generated with four‐dimensional Quantum Cellular neural Network (QCNN) iteration ,the first three groups are used for chaotic sequence pool ,and the other one is used to generate the initial value of the Logistic map to increase the dynamics of the initial value .Then ,to avoid repeatedly solving the high dimensional chaotic systems ,the sequence of the calculation key is selected from the chaotic sequence pool according to the index generated by the Logistic map .After calculation ,the encryption key is obtained ,which realizes the fast generation of the key .Finally ,some key elements ,such as partial sign bits and information bits in video coding , are effectively encrypted for reducing the amount of encrypted data .Experiments show that the proposed encryption algorithm for 70 frames of video coding delay is less than 0 .6% .Through the key space analysis , NIST SP 800‐22 test , known plaintext attack and inference attack experiment analysis ,it is show n that the proposed video encryption algorithm has the advantages of large key space ,good random key ,strong attack resistance and high security .In addition ,the algorithm does not change the video compression ratio to conform video encoding format specification .By quickly generating secure keys with only encrypting the key video syntax elements ,the H .264／AVC video encryption delay is effectively reduced .%针对采用混沌视频加密算法后视频编码延迟大的问题,提出了一种H .264／AVC视频的快速安全加密算法.首先设计了密钥生成方案,由4维量子细胞神经网络迭代产生4组混沌序列,使用前3组混沌序列作为计算密钥的混沌序列池,后1组混沌序列作为Logistic混沌映射的初值以提高其初值的动态性.然后,利用Logistic混沌映射生成的索引从混沌序列池中选择用于生成密钥的序列组,避免了多次求解高维混沌系统,实现了密钥的快速生成.最后,本算法选择视频编码中的部分关键语法元素作为加密对象,减少了加密的数据量,对70帧的视频编码的延迟小于0 .6%,通过密钥空间分析、NIST SP 800‐22测试、已知明文攻击和推理攻击等实验分析表明,本文提出的视频加密算法具有密钥空间大、密钥随机性好、抗攻击性能强和安全强度高的优点.此外,算法不改变视频压缩比、符合视频编码格式规范,通过快速生成密钥和只加密视频关键语法元素有效地降低了 H .264／AVC视频的加密延迟.
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