基于复合混沌与仿射变换的彩色图像加密算法

针对彩色图像的特点,提出基于由tent映射和改写Logistic、Cubic、Chebychev映射构造四进制复合混沌系统、三维仿射变换、扰动密钥参数扩散和RGB分量联合置乱的彩色图像空域加密算法。该算法RGB相关性少,密钥空间大,明密文映射关系复杂,能抵抗穷举、明文、差分和统计分析攻击。利用matlab7.0对经典水印、人物、风景类型的彩色图像进行仿真试验。试验结果(加密、直方图分析、相邻像素相关性、密钥和密文敏感性、信息熵、峰值信噪比和相似度)表明,该算法具有加密效果好和安全性高的特点。

Color image encryption algorithm based on complex chaos and affine transform

According to the characteristics of the color image,the color image airspace encryption algorithm was proposed based on quaternary compound chaotic system structured by the tent map and the Logistic, Cubic, Chebychev map rewrited, the three dimensional affine transformation, diffusion of disturbance key parameters and RGB components joint scrambling.The algorithm that correlation of RGB was very small, key space was huge large, bright ciphertext mapping relationship was complex, could resist exhaustion, plaintext, difference and statistical analysis attacks. The simulation experiment of the classic watermark, figures, landscape types of color images were achieved by matlab7.0. The experimental results(encryption, histogram analysis, the correlation between adjacent pixels, key and the ciphertext sensitivity, information entropy, peak signal-to-noise ratio and similarity)showed that the algorithm has good encryption effect and high safety features.