基于差异混合掩码与混沌Gyrator变换的光学图像加密算法

Optical Image Encryption Algorithm Based on Differential Mixed Mask and Chaotic Gyrator Transform

为了提高光学加密技术的抗选择明文攻击能力与未知攻击下的解密质量,该文设计了基于差异混合掩码与混沌Gyrator变换的光学图像加密算法。将输入明文转换成相应的快速响应码;考虑明文特性,根据Logistic映射,生成一个混沌相位掩码;同时,联合径向希尔伯特与波带片相位函数,将其与混沌相位掩码融合,构建了混合相位掩码;随后,利用明文图像迭代Logistic映射所输出的随机序列来计算Gyrator变换的旋转角度,结合混合相位掩码,对快速响应码进行调制,形成Gyrator频谱;引入等量分解技术,将Gyrator频谱分割为两个分量,并设置不同的阶数,形成两个差异螺旋相位掩码;利用奇异值分解(SVD)方法,将其中一个Gyrator频谱分量进行处理,并联合两个差异螺旋相位掩码,分别对其相应的正交矩阵进行编码;最后,通过组合编码后的正交矩阵与对角矩阵,基于可逆SVD技术,输出加密密文。理论分析了所提算法抵抗明文攻击和裁剪攻击的能力,以及加密结果针对密钥变化的敏感性水平。实验结果验证了所提算法拥有良好的安全性能。

In order to improve the ability of anti-chosen plaintext attack and decryption quality under unknown attack in current optical encryption technology,an optical image encryption algorithm based on chaotic Gyrator transform and differential mixed mask is proposed.The input plaintext is converted into its corresponding Quick Response(QR)code.The chaotic phase mask is generated according to the Logistic map.At the same time,the radial Hilbert and the zone plate phase function are combined to fuse with the chaotic phase mask for constructing the mixed phase mask.Then,a random sequence of Logistic chaotic maps is used to calculate the rotation angle of the Gyrator transformation,and the QR code is modulated to form Gyrator spectrum by combining the mixed phase mask.The Gyrator spectrum is divided into two components by introducing the equivalent decomposition technique,and two differential spiral phase masks are obtained by setting up different orders.Then,the Singular Value Decomposition(SVD)is introduced to process one of the Gyrator spectral components so that its corresponding orthogonal matrix is encoded by combining two differential phase masks.Finally,by combining the encoded orthogonal matrix and diagonal matrix,the encrypted cipher is outputted based on thereversible SVD technology.The ability of resisting plaintext attack and clipping attack,as well as the sensitivity level of the encryption results to key change is analyzed theoretically.Experimental results show that the algorithm has good security performance.