Using chaotic system for image encryption is a feasible and popular research interest. In this paper, a compound Sine-Piecewise Linear Chaotic Map is proposed to improve the chaotic characteristics of the original chaotic map. Compared with the original chaotic system, the proposed compound chaotic system has better dynamics performances, larger parameter space, which is more suitable for cryptographic applications. Furthermore, an image encryption algorithm based on this chaotic model and varying DNA coding is proposed. In this encryption algorithm, a novel method is provided to convert decimal numbers to binary numbers. Several numerical experiments show that the proposed encryption algorithm has good security performances, and is competitive with other chaos-based image encryption algorithms.

使用混沌系统进行图像加密是一个可行且流行的研究兴趣。本文提出了一种复合正弦-分段线性混沌图，以改善原始混沌图的混沌特性。与原混沌系统相比，所提出的复合混沌系统具有更好的动力学性能，更大的参数空间，更适合密码学应用。此外，提出了一种基于该混沌模型和可变DNA编码的图像加密算法。在该加密算法中，提供了一种将十进制数转换为二进制数的新方法。多次数值实验表明，所提出的加密算法具有良好的安全性能，与其他基于混沌的图像加密算法相比具有竞争力。