基于超混沌系统的多权限多图像加密算法

为有效改善多图像加密质量及其对数据传输的安全性,提出一种基于超混沌系统的多权限多图像加密算法.首先,将L幅明文图像分别进行分段线性混沌映射(piece-wise linear chaotic map, PWLCM)的双层交叉耦合操作,并通过异或进行合并得到类噪声图像;接着,采用最低有效位嵌入算法将类噪声图像嵌入到第L+1幅明文图像信息中,得到半加密图像;最后,通过结合一维的cubic映射和一维帐篷映射,产生一个二维cubic-帐篷混沌映射(two-dimensional cubic-tent modular map, 2D-CTMM),利用其对半加密图像扩散后进行双层阶梯置乱,得到密文图像.实验结果表明:所提方法对明文以及密钥十分敏感,密钥空间大,可以有效抵御统计攻击和差分攻击,并且该算法在保证安全性的前提下,实现了用户多权限解密以及用户部分解密工作.

Multi-authority Multi-image Encryption Algorithm Based on Hyperchaotic System

To effectively improve the quality of multi-image encryption and its security for data transmission, this study proposes a multi-authority multi-image encryption algorithm based on a hyperchaotic system. Specifically, bilayer cross-coupling based on the piece-wise linear chaotic map (PWLCM) is applied to L plaintext images respectively. The results are merged by exclusive-OR (XOR) to obtain a noise-like image. Then, the least significant bit embedding algorithm is used to embed the noise-like image into the (L+1)th plaintext image to obtain a semi-encrypted image. Finally, a one-dimensional cubic map is combined with a one-dimensional tent map to generate a two-dimensional cubic-tent modular map (2D-CTMM). A ciphertext image is obtained by two-step scrambling of the semi-encrypted image after it is diffused with the 2D-CTMM. The experimental results show that the proposed method, highly sensitive to plaintext and key with a large key space, can effectively resist statistical attacks and differential attacks. Moreover, the proposed algorithm enables multi-authority decryption and partial decryption by different authorized users.