Logistic混沌序列和DES算法的图像加密方法

Image encryption algorithm based on Logistic chaotic sequence and DES

为了保证数字图像在网络传输中的安全性和可靠性,基于数据加密标准(DES)算法和Logistic混沌映射,提出了一种结合置乱与扩散的图像加密算法。首先,生成两组经过改进的Logistic混沌序列,应用于迭代运算、比特变换等加密过程;然后,根据对混沌序列排序的顺序,实现像素的置乱的过程;最后,对DES算法的初始置乱和密码函数进行改进,使像素的扩散更为有效,同时结合随机置乱,最终得出加密图像。对该加密系统在信息熵、相关性和密钥空间等方面的安全性能进行分析,结果表明该图像加密方法具有密钥空间大、运算速度快、抗攻击能力强等特点,能够有效并安全的掩盖明文信息,具有较好的加密效果。

To ensure the security and reliability of the transmission of digital images in the network, an image encryption algorithm was proposed based on the sequences of Logistic map and DES（ Data Encryption Standard） combined with scrambling and diffusion. Firstly, two modified chaotic sequences of Logistic maps were generated and applied to encryption processes such as iteration and bit encryption; secondly, pixels were scrambled according to the sorted order of the chaotic sequences; finally, the encrypted image was generated with more effective diffusion and more random scrambling, as the initial scrambling and cryptographic function of DES were modified. After the encryption system was analyzed in terms of entropy,correlation and key space, the result shows that this image encryption method is able to cover up plaintext effectively and safely with huge key space, high speed, good anti-attack capability.