Xu Jiangjian, Zhao Bing, Wu Zeming
Electronic Engineering College, Heilongjiang University, Harbin 150080, China.
Entropy (Basel). 2022 Jan 26;24(2):186. doi: 10.3390/e24020186.
In response to the problems of high complexity and the large amount of operations of existing color image encryption algorithms, a low-complexity, low-operation color image encryption algorithm based on a combination of bit-plane and chaotic systems is proposed that is interrelated with plaintext information. Firstly, three channels of an RGB image are extracted, and the gray value of each pixel channel can be expressed by an eight-bit binary number. The higher- and lower-four bits of the binary gray value of each pixel are exchanged, and the position of each four-bit binary number is scrambled by a logistic chaotic sequence, and all the four-bit binary numbers are converted into hexadecimal numbers to reduce the computational complexity. Next, the position of the transformed image is scrambled by a logistic chaotic sequence. Then, the Chen chaos sequence is used to permute the gray pixel values of the permuted image. Finally, the gray value of the encrypted image is converted into a decimal number to form a single-channel encrypted image, and the three-channel encrypted image is synthesized into an encrypted color image. Through MATLAB simulation experiments, a security analysis of encryption effects in terms of a histogram, correlation, a differential attack, and information entropy is performed. The results show that the algorithm has a better encryption effect and is resistant to differential attacks.
针对现有彩色图像加密算法复杂度高、运算量大的问题，提出一种基于位平面与混沌系统相结合的低复杂度、低运算量且与明文信息相关的彩色图像加密算法。首先，提取RGB图像的三个通道，每个像素通道的灰度值可用八位二进制数表示。将每个像素二进制灰度值的高四位和低四位进行交换，并用逻辑混沌序列对每个四位二进制数的位置进行置乱，然后将所有四位二进制数转换为十六进制数以降低计算复杂度。接下来，用逻辑混沌序列对变换后的图像位置进行置乱。然后，使用陈氏混沌序列对置乱后图像的灰度像素值进行置换。最后，将加密图像的灰度值转换为十进制数，形成单通道加密图像，并将三通道加密图像合成加密彩色图像。通过MATLAB仿真实验，从直方图、相关性、差分攻击和信息熵等方面对加密效果进行了安全性分析。结果表明，该算法具有较好的加密效果，且能抵抗差分攻击。
