摘要： 当前混沌加密系统普遍采用单向扩散机制，导致计算效率和加解密速度较低，且都忽略了时间延迟现象，使其序列自相关性较高，无法满足安全、实时的传输需求。为此，提出一种双向扩散机制融合时间延迟的图像加密算法。迭代计算超混沌LORENZ系统得到一组超混沌序列，通过时间延迟函数与logistic映射将时间延迟引入到超混沌序列中，得到一组新序列，并利用位置集合置乱方法对该序列所得到的位置集合图像重新设置，采用密钥流机制量化新序列，通过双向扩散机制加密图像。仿真实验结果显示，与传统加密算法相比，该算法的加密机制较安全，密钥空间较大，计算效率较高。
关键词:
双向扩散机制,
时间延迟,
位置集合置乱,
自相关性,
密钥空间,
计算效率
Abstract: To defects such as the low speed of encryption and decryption, as well as the low computation efficiency induced by the single diffusion mechanism in the current chaotic-based encryption system, the high autocorrelation of chaotic sequence is induced by ignoring the time delay, resulting in the misadventure performance of encryption quality, low security, as well as not satisfying the security and real-time transmission in the face of high resolution, large capacity image. The time delay function and bilateral direction diffusion mechanism are proposed, using the fast image encryption algorithm based on bilateral direction diffusion mechanism integration with time delay to solve above problems. The hyper-chaotic LORENZ system is iterated to get one group hyper-chaotic sequence. The time delay is introduced into the hyper-chaotic sequence by the time delay and logistic map to obtain the new sequence. The permutation method of position set is used to permute the pseudo-random sequence on the time delay to get one position set, and it is used to permute the image. The key stream mechanism is used to treat the new pseudo-random sequence, and the bilateral direction diffusion mechanism is used to encrypt image. Experimental results show that the image encryption algorithm has better encryption performance. The key space is larger. The anti-plaintext attack property is greatly enhanced, and the variation of autocorrelation of chaotic sequence is smaller.
Key words:
bilateral direction diffusion mechanism,
time delay,
permutation of position set,
autocorrelation,
key space,
computation efficiency
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