基于混沌系统与元胞自动机的图像加密算法

Image Encryption Algorithm Based on Chaotic System and Cellular Automata

摘要: 由于互联网的开放性和共享性，作为重要信息载体的图像在传输过程中时刻面临着巨大风险。图像加密是保证图像安全的重要手段，通过将图像加密为密文来保护图像的原始信息。本文提出了一种针对RGB彩色图像的加密算法，该加密算法基于混沌系统与元胞自动机，并且可以利用彩色图像三通道的特性。加密算法使用一个常见的三维混沌系统生成加密所需的随机序列，并结合第三类初等元胞自动机进一步提高了这些序列的随机性。为了保证图像的整体质量，本文设计了一种RGB像素合并的方法，将彩色图像三个通道对应的像素合并起来处理，并在过程中混淆三个通道的像素来改变图像的原始像素信息。为了进一步提高安全性，算法还使用了祖冲之算法中的替换盒替换图像的像素信息来模糊密文和密钥的关系。实验结果表明，提出的图像加密算法可以有效加密图像信息，并具备抵抗多种攻击的能力。

Abstract: Due to the openness and sharing nature of the internet, images, as important carriers of information, face significant risks during transmission. Image encryption is an essential method to ensure image security, protecting the original information of the image by converting it into ciphertext. This paper proposes an encryption algorithm for RGB color images, which is based on chaotic system and cellular automata, and takes advantage of the three-channel nature of color images. The algorithm uses a commonly used three-dimensional chaotic system to generate random sequences required for encryption and further enhances the randomness of these sequences by combining them with a third-class elementary cellular automaton. To ensure the overall quality of the image, this paper designs a method for RGB pixels merging, where the pixels corresponding to the three channels of the color image are combined for processing, and during this process, the pixels of the three channels are shuffled to alter the original pixel information of the image. To further improve security, the algorithm also utilizes substitution boxes from ZUC algorithm to replace the image’s pixel information, thereby obscuring the relationship between the ciphertext and the key. Experimental results show that the proposed image encryption algorithm can effectively encrypt image information and is capable of resisting various types of attacks.