In this paper, we propose a novel encryption algorithm using cascaded quaternion gyrator transforms that allows protecting multiple color images with efficiency at once. The originality is reflected in the integration of quaternion algebra with a cascaded encryption structure. First, image RGB channels are constituted into three imaginary parts of a quaternion matrix. A cascaded encryption structure is constructed to cooperate with the vortex phase mask, which is easy to transmit and saves storage. Then, a quaternion gyrator transform is conducted, after which the phase is extracted to serve as the decryption key while the amplitude is used as the real part of the following quaternion matrix. Finally, the amplitude of the last gyrator transform is scrambled to obtain the ciphertext. All phase matrices are further modulated by a secondary image phase mask for additional security. Numerical simulations have been conducted to verify the validity of the proposed algorithm. Experiments on several data test set demonstrate the robustness of the proposed method to various attacks.

在本文中，我们提出了一种使用级联四元数回转器变换的新型加密算法，该算法允许一次有效地保护多个彩色图像。独创性体现在将四元数代数与级联加密结构相结合。首先，图像 RGB 通道被构成一个四元数矩阵的三个虚部。构建级联加密结构与涡旋相位掩码配合，便于传输，节省存储。然后，进行四元数回转器变换，然后提取相位作为解密密钥，而幅度用作以下四元数矩阵的实部。最后对最后一次回转器变换的幅度进行加扰，得到密文。所有相位矩阵都由二次图像相位掩模进一步调制，以提高安全性。已经进行了数值模拟以验证所提出算法的有效性。在几个数据测试集上的实验证明了所提出的方法对各种攻击的鲁棒性。