基于交叉控制与多方向异扩散的图像加密算法

Image encryption algorithm based on cross control and multi-direction different diffusion

为了削弱当前加密密文存在的周期性,改善算法的安全性与动态性,提出了一种多方向扩散图像加密算法。将初始图像分割为2个均等的子块,引入Logistic映射获取2个随机序列。通过设计量化机制形成新的数组,并将其重新组合为2个矩阵,建立像素交叉控制策略,对子块完成高度混淆,降低置乱周期性。设计了4方向折叠加密方法,每一个不同的扩散方向对应一个扩散函数,从4个方向来实现像素扩散,削弱扩散周期性。结果表明与当前混沌加密技术相比,所提算法具有更高的加密安全性与抗攻击能力及较高的保密性,能够提高图像抵御网络攻击的能力,确保图像信息安全。

In order to weaken the periodicity of encrypted cipher and improve security and dynamics of the algorithm, an image encryption algorithm based on multi-direction diffusion is proposed. The initial image is divided into two equal blocks, and two random sequences are obtained by introducing Logistic mapping. New arrays are formed by designing quantization mechanism, and they are recombined into two matrices. The pixel cross control strategy is established. Highly confusion of sub-blocks is achieved and the periodicity of scrambling is reduced. The four direction folding encryption method is designed in which each diffusion direction corresponds to a diffusion function for diffusing the pixels form four directions to weaken diffusion periodicity. Results show that proposed algorithm has higher encryption security, anti-attack resistance and privacy compared with the current chaotic encryption techniques, which can improve the ability to resist network attacks of image, and ensure the image information security.