基于快速响应码约束的光学图像加密算法

Optical Image Encryption Algorithm Based on Quick Response Code Constraint

为提高光学图像加密算法的安全性与解密质量,方便密钥的存储、管理与传输,提出一种基于快速响应(QR)码约束与混沌Gyrator变换的图像加密算法。引入二维耦合混沌系统,利用明文像素对其进行迭代后输出2个随机相位掩码。通过2个混沌序列来计算2个Gyrator变换的旋转角度,然后利用明文生成相应的QR码,并将其置于2个随机相位掩码结构的输入平面,通过两级Gyrator变换输出一个实值密文。同时,借助QR码的支撑约束条件对传统的相位检索技术进行改进,最终从密文中检索到初始的QR码后解密图像。实验结果表明,与借助圆谐分量展开与Gyrator变换实现光学图像加密的算法相比,该算法具有较高的安全性与解密质量,在噪声攻击下,其复原图像的失真度较低。

In order to improve the security and decryption quality of optical image encryption algorithm and facilitate key storage,management and transmission,an image encryption algorithm based on Quick Response(QR)code constraint and chaotic Gyrator transform is proposed.A two-dimensional coupled chaotic system is introduced,and two random phase masks are output after iteration using plaintext pixels.Two chaotic sequences are used to calculate the rotation angles of the two Gyrator transforms,and then the corresponding fast response codes are generated by plaintext.The codes are placed on the input plane of two random phase masks and a real ciphertext is output by two-stage Gyrator transforms.At the same time,the traditional phase retrieval technology is improved by using the support constraints of the QR code,and the original QR code is retrieved from the ciphertext and the decrypted image is decrypted.Experimental results show that the proposed algorithm has higher security and decryption quality than the optical image encryption algorithm based on circular harmonic component expansion and Gyrator transform,under noise attack,the distortion of restored image is lower.