基于快速响应码的非线性光学图像加密算法

Nonlinear optical image encryption based on fast response code

为增强加密系统的抗破译能力,提出快速响应码耦合Shearlet变换的非线性光学加密算法。引入非线性复合混沌系统,构建交叉置乱方法,改变明文的像素位置;借助二维码生成器,将置乱结果转换成对应的快速响应码QR(quick response)码;采用Shearlet变换,对QR码实施5级分解,输出5个剪切系数,利用一个安全图像与第一个剪切系数互换,联合其它4个系数,借助可逆Shearlet变换,生成过渡图像;设计调制融合掩码,基于Gyrator变换,对过渡图像实施加密,获取Gyrator频谱;通过幅度-相位截断,将Gyrator频谱实施分割,输出密文。测试数据表明,与已有的光学加密方法相比,所提方案具备更高加密安全性与复原质量。

To enhance the anti-cracking ability of encryption system,a non-linear optical image encryption algorithm based on quick response code and Shearlet transform was designed.The cross-scrambling method was constructed by introducing a non-linear compound chaotic system to change the pixel position of the initial image.The permutation result was converted into the corresponding quick response code by means of a two-dimensional code generator.The QR code was decomposed into five Shear coefficients by five levels of Shearlet transform.A secure image and the first shearing coefficient were used to interchange,combining the other four coefficients,the transition image was generated by reversible Shearlet transform.The modulation fusion mask was designed,and the Gyrator spectrum was obtained using the Gyrator transform to encrypt the transition image.By means of amplitude-phase truncation,the Gyrator spectrum was divided into the ciphertext.The test data show that compared with the existing optical encryption methods,the proposed scheme has better encryption security and restoration quality.