基于多参数分阶角变换与四元超复数的多图像同步无损加密算法

Multi-image Synchronization Encryption Algorithm Based on Multi-parameter Fractional Angle Transformation and Four Element Super-complex Number

为了对多幅图像实现同步无损加密,设计了基于多参数分阶角变换与四元超复数的多图像同步加密算法.首先,利用4个输入明文的像素,设计混沌置乱技术,充分改变每幅图像的像素位置,输出4个混淆密文;利用DCT(Discrete Cosine Transform)技术与锯齿扫描机制,将置乱图像变成4个一维DCT系数矩阵;引入四元超复数方法,将其中1个置乱密文对应的DCT系数作为实部,剩余3个混淆图像为虚部,从而构成融合矩阵;基于逆DCT变换,将融合系数矩阵变为复合图像;建立了多参数分阶角变换,构建了加密函数,输出幅度与相位信息,消除解密图像的失真问题.测试数据显示:与已有多图像加密机制相比,所提技术可对4幅图像完成同步加密,可消除解密失真,具备更高的安全性.

In order to achieve simultaneous lossless encryption for multiple images,a multi-image synchronization encryption algorithm based on multi-parameter fractional angle transformation and four element discrete Fourier transform has been proposed in this paper.Firstly,the chaotic permutation mechanism was designed based on four plain pixels to change the pixel position of each image.Then these permutation ciphers were transformed into 1 DDCT coefficient matrix based on DCT technology and sawtooth scanning mechanism.The four element discrete Fourier transform was designed by embedding the complex-number method into Fourier transform,and the fusion matrix was constructed by taking the DCT coefficients as the real part,while remaining three confused images as imaginary part.Then the fusion coefficient matrix was transformed into a composite image based on inverse Fourier transform.Finally,the multi-parameter fractional angle transformation was constructed to design the encryption function for outputting diffusion cipher and phase.The experimental results show that this algorithm can achieve the simultaneous encryption of four images,and has stronger sensitivity and the ability of anti-plaintext attack,as well as higher quality of decryption compared with the current multi image encryption technology.