基于Logistic-Sine-Cosine映射的图像加密算法

为了提高数字图像加密的速度和算法的安全性，提出了基于Fridrich框架的加密算法。通过Fisher-Yates变换置乱原始图像打破像素间的强相关性，再利用滤波器在RGB平面上进行滤波得到密文。Logistic-Sine-Cosine复合混沌系统具有良好的混沌特性，且时间复杂度低。密钥由输入参数和明文的SHA-512值共同决定，对明文高度敏感。二维滤波器扩散效果良好，其滤波器模板由明文和密钥决定并引入了伪随机像素值，在提升扩散效果的同时增强了系统抗差分攻击的能力。仿真结果表明，密文图像像素分布近似均匀、像素关联性弱、密钥空间足够大、密钥敏感性高，能够有效抵抗暴力、裁剪、差分等常见攻击，具有较高的安全性，且算法时间复杂度较低。

Image Encryption Algorithm Based on Logistic-Sine-Cosine Mapping

Aiming at improving the speed and security of digital image encryption, an encryption algorithm based on the Fridrich framework is proposed. The Fisher-Yates transform is used to scramble the original image to break the strong correlation between pixels, and then the filter is used to filter the image on the RGB plane to obtain the ciphertext. Logistic-Sine-Cosine compound chaotic system has good chaotic characteristics and low time complexity. The key is determined by the input parameters and the plaintext SHA-512 value, and is highly sensitive to the plaintext. The two-dimensional filter diffuses well, its filter template is determined by plaintext and key , and pseudo random pixel value is introduced to improve the diffusion effect and enhance the system''s resistance to differential attacks at the same time. Simulation results show that the ciphertext image has an approximately uniform pixel distribution, weak pixel correlation, a large key space and high key sensitivity. The algorithm can resist common attacks such as brute force attack, cropping attack and differential attack with high security and low time complexity.