为实现对多幅图像完成同步加密，并提高密文的安全性与抗几何变换攻击能力，提出基于快速响应码 (QR)与级联分数阶 Fourier变换的多图像光学加密算法。借助 Logistic映射，获取随机掩码，联合 Fresnel波带 、 Hilbert模型，构建调制掩码；引入复数理论，借助模板图像对第一幅明文实施处理，形成复数图像；采用分数阶 Fourier变换，借助调制掩码，对复数图像实施处理，并基于相位-幅度截断机制，得到相位分布与密钥； 再结合相位截断方法与分数阶 Fourier变换，设计级联快速傅里叶变换( FFT)加密机制，通过调制掩码与相位分布，对剩余的多幅明文实施频域变换处理，输出融合幅度图像，并将其转换为对应的 QR码；引入 Gyrator变换 ，通过相应的光电装置，利用激光束对 QR码完成干涉处理，得到密文。测试数据表明：相对已有的多图像光学加密技术，本算法具备更高的保密安全性与抗攻击能力，在裁剪变换下，其复原图像的失真度更小。

In order to achieve synchronous encryption of multiple images and improve the security of ciphertext and the ability to resist geometric transformation attacks, the multi-image optical encryption algorithm based on quick response and cascaded fractional transform is proposed in this paper. By introducing complex number theory, the first plaintext is processed with template image to form complex image. The complex image is decomposed based on the phase–amplitude truncation mechanism to obtain the phase distribution. With the help of Logistic map, the random masks are obtained, and the modulation masks are constructed by combining Fresnel band and Hilbert models. Combining the phase truncation method with fractional order Fourier transform, a cascaded Fast Fourier Transform(FFT) encryption mechanism is designed, and the remaining plaintext is processed by frequency domain transformation based on modulating mask and phase distribution to output the amplitude image, then it is converted into corresponding Quick Response(QR) code. The Gyrator transform is introduced, and the QR code is interfered by laser beam through the corresponding photoelectric device to get the cipher. The test data show that compared with the existing multi-image optical encryption technology, the proposed algorithm has higher security and anti-attack ability, and the distortion of the restored image is smaller under the clipping transformation.