To obtain a more secure colour image cryptosystem without complex construction, this paper presents a general simple colour image encryption model with a very high level of security, and that is based on two nearby orbits of chaotic systems. First, the initial value of a one-dimensional (1D) chaotic map is obtained using plaintext. Then, we obtain two nearby orbits of 1D chaotic maps to generate three new chaotic signals. Next, the generated systems independently encrypt the red, green and blue components (RGB) of the colour image. Finally, the three encrypted images are combined to obtain the final encrypted image. Simulation results show that our method is simple, effective and passed all NIST tests and part of TestU01 test. Since the proposed method is related to plaintext, it has much higher security level compared with the most recently reported chaos-based image algorithms. More importantly, the 1D logistic cryptosystem based on our method has a large key space with higher security.

为了获得一个没有复杂结构的更安全的彩色图像加密系统，本文提出了一种具有很高安全级别的通用简单彩色图像加密模型，该模型基于两个相邻的混沌系统轨道。首先，使用明文获得一维（1D）混沌图的初始值。然后，我们获得1D混沌图的两个相邻轨道，以生成三个新的混沌信号。接下来，生成的系统独立加密彩色图像的红色，绿色和蓝色分量（RGB）。最后，将三个加密图像组合以获得最终的加密图像。仿真结果表明，该方法简单，有效，并通过了所有NIST测试和部分TestU01测试。由于建议的方法与纯文本相关，与最近报道的基于混沌的图像算法相比，它具有更高的安全级别。更重要的是，基于我们的方法的一维逻辑密码系统具有较大的密钥空间和更高的安全性。