摘要：

图像加密是保护图像安全的重要方法, 现有的图像加密方案安全性不高且加解密效率较低, 无法抵御多种类型的攻击。针对上述问题, 提出一种基于全置乱超混沌序列和多进制脱氧核糖核酸(DNA)编码的图像加密算法, 以提高加密效率同时保证密文图像的安全性。首先, 结合灰度图像的内容, 使用图像哈希算法和外部密钥生成五维超混沌系统和逻辑映射的初始值; 其次, 将原始图像转换为四值图像, 使用五维超混沌系统和逻辑映射生成的混沌序列对图像进行DNA加密, 包括DNA编码、DNA置乱、DNA扩散和DNA解码4个阶段; 最后, 对图像进行位平面分解, 利用五维超混沌系统和逻辑映射生成的随机矩阵分别与高四位平面和低四位平面做异或运算, 得到最终的密文图像。实验结果表明, 该图像加密算法具有密钥空间大、密钥敏感性强、加密效果良好、加密效率高等优点, 能够抵抗统计分析、差分攻击、裁剪攻击、噪声攻击等多种常规攻击方式。

关键词: 图像加密, 超混沌系统, 四值图像, DNA加密, 位平面

Abstract:

Image encryption is a crucial technique for safeguarding image security. However, existing encryption schemes often lack robustness, exhibit low efficiency in encryption and decryption processes, and are vulnerable to various attacks. To address these challenges, this study proposes an image encryption algorithm that integrates fully scrambled hyperchaotic sequences with multi-ary Deoxyribonucleic Acid (DNA) encoding, enhancing encryption efficiency while maintaining robust ciphertext image security. The proposed method involves three main stages. First, the grayscale image content is combined with an image hash algorithm and an external key to generate initial values for the five-dimensional hyperchaotic system and logical map. Second, the image is converted into a four-valued format, and a random sequence derived from the hyperchaotic system and the logical map is used to perform DNA encryption in four stages: DNA encoding, scrambling, diffusion, and decoding. Finally, the image is decomposed into bit planes, where XOR operations are applied to both high and low four-bit planes using a random matrix generated by the hyperchaotic system and logical map, resulting in the final ciphertext image. Experimental results demonstrate that the proposed image encryption algorithm offers a large key space, strong key sensitivity, and high encryption efficiency while delivering effective encryption. Furthermore, it exhibits robust resistance to conventional attacks, including statistical analysis, differential attacks, clipping, and noise-based interference.

Key words: image encryption, hyperchaotic system, four-valued image, DNA encryption, bit plane