空间填充曲线耦合时延映射格子多图像加密算法

Multi-Image Synchronous Encryption Algorithm Based on Space Filling Curve Coupling Time-delay Map Lattices

为了解决当前图像加密算法无法对多个图像(≥3)完成同步扩散的不足,基于叠加融合思想,将多幅图像以矩阵形式融合成信息叠加矩阵,设计了空间填充曲线耦合时延映射格子的多图像同步加密算法。利用DCT(Discrete Cosine Transform)技术将所有初始图像转换为系数矩阵,同时,为了提高算法的自适应性与鲁棒性,引入锯齿空间填充曲线,对这些明文矩阵完成扫描,生成多个1D置乱数组;构造矩阵叠加模型,将这些1D数组迭代成复杂组合矩阵;再利用IDCT(Inverse Discrete Cosine Transform)变换,获取组合置乱密文;并将置乱密文演变成像素数组,基于耦合映射格子,生成密钥流,再嵌入时间变化延迟,设计了像素扩散模型,完成加密。实验数据表明:该算法能够完成多图像(≥3)同步加密,具备较强的防攻击能力;与其他图像加密机制相比,运用该算法得到的初始明文与解密图像之间的相似度更高。

In order to solve the defect that current image encryption algorithm can not finish synchronous diffusion multi-images （ ≥ 3 ） , the multi-image synchronous encryption algorithm based on space filling curve coupling time-delay map lattices according to the superposition fusion idea for transforming multi- images into superposition of information matrix was designed. All the initial images were converted into coefficient matrix by using the DCT（ Discrete Cosine Transform）, at the same time, in order to improve the adaptability and robustness of the algorithm, 1 D permutation array was produced by introducing the space filling curve to scan these plaintexts; Then the matrix superposition model was constructed to convert 1 D iterative array into complex combination matrix; and the permutation cipher was got by IDCT （Inverse Discrete Cosine Transform）; Finally, the pixel diffusion model was designed to finish encryption by key stream generated by coupled map lattice and embedding time variations delay, as well as scrambling ciphertext evolved into an pixels array. Experimental data show that this algorithm can complete multiple images （ ≥ 3 ） synchronization encryption with strong anti-attack capability, and compared with other image encryption mechanism, the similarity between the initial plaintext image and the decrypted image is higher.