基于超混沌映射的位平面彩色图像加密算法

A Novel Hyper-Chaos-Based Colorimage Encryption Algorithm Using Bit-Level Permutation and Diffusion

摘要: 本文将4D Lorenz混沌映射应用在彩色图像加密中，并简要的分析了4D Lorenz混沌映射的动力学性质，基于这个映射，设计了一种位平面置乱和扩散的图像加密算法。在传统的置乱–扩散结构中，置乱和扩散一般是两个独立的部分，本文算法将位平面置乱和扩散同时进行。位平面置乱采用循环移位，扩散采用异或和取反操作。此外为了提高抵抗已知明文攻击和选择明文攻击的能力，与原文相关的SHA-256将应用在密钥流产生器中，因此不同的明文将产生完全不同的密钥流。最后对本文提出的加密算法进行了相关的性能分析，如密钥分析、敏感性分析、统计分析等等，基于所有仿真实验分析，本文所提出的算法，在数字图像加密中具有较好的性能。

Abstract: In this paper, a 4D Lorenz map is proposed using in cryptography. Performance evaluations show that it has hyper-chaotic behavior, wide chaotic range and large complexity. Based on this map, a novel image encryption algorithm is designed by employing bit-level permutation and diffusion. In traditional permutation-diffusion structure, the permutation and substitution generally are two independent parts. In this article, encryption algorithm is designed by employing bit-level permutation and diffusion simultaneously. The bit-level permutation is performed by circular shifting, and the bit-level diffusion is carried out by exclusive or (xor) and reverse operations. In addition, to achieve the better ability of resisting chosen-plaintext or known-plaintext attack, the substitution key stream generated using SHA-256 in our method is dependent on the plain image. Consequently, different plain images produce the distinct key stream for substitution. The simulation results and performance analysis show that the proposed image encryption algorithm is both secure and reliable for image encryption.