基于改进Lorenz混沌系统的图像加密新算法

发布时间：2018-05-28 22:08

本文选题：Lorenz系统 + 图像加密　；参考：《中南大学学报(自然科学版)》2017年10期

【摘要】：为了提高图像加密算法的加密安全性和抗攻击能力,提出一种基于改进Lorenz混沌系统的图像加密新算法。首先,将Lorenz系统中的1个非线性项用指数函数项与单变量2次平方项的和替代;然后,分析该改进Lorenz系统的动力学特性,证实其混沌特性;最后,利用该混沌映射生成分别用于置乱加密和替代加密的2组密钥序列,进行图像的加密和解密操作:在置乱加密阶段,将图像像素灰度进行升序排列,并与置乱加密密钥序列结合实现像素位置置乱;在替代加密阶段,采用密文反馈的加密方式修改像素灰度。研究结果表明:该算法能有效抵御选择明文攻击,密文图像像素具有类随机均匀分布特性,且相邻像素具有零相关特性,拥有192 bit的密钥空间且对密钥非常敏感。
[Abstract]:In order to improve the encryption security and anti-attack ability of image encryption algorithm, a new image encryption algorithm based on improved Lorenz chaotic system is proposed. First, a nonlinear term in Lorenz system is replaced by the sum of exponential function term and quadratic square term of single variable. Then, the dynamic characteristics of the improved Lorenz system are analyzed and its chaotic properties are proved. The chaotic map is used to generate two sets of key sequences, which are used for scrambling encryption and replacing encryption respectively, and then encrypt and decrypt the image. In the scrambling encryption stage, the grayscale of the image pixels are arranged in ascending order. Combining with the scrambling encryption key sequence, the pixel position scrambling is realized; in the phase of replacing encryption, the pixel gray level is modified by ciphertext feedback encryption. The results show that the algorithm can effectively resist the attack of selective plaintext. The pixels of ciphertext images have the property of random and uniform distribution, and the adjacent pixels have the property of zero correlation. The algorithm has a key space of 192 bit and is very sensitive to the key.
【作者单位】：中南大学软件学院;湖南城市学院信息与电子工程学院;
【基金】：湖南省教育厅科研项目(17C0296) 益阳市指导性科技计划项目(20165111)~~
【分类号】：TP309.7;TP391.41

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