云计算环境下的QR码双重加密复合数字水印算法

Digital Watermarking Algorithm of QR Code Double Encryption Composite in Cloud Computing Environment

为了确保上传到“云”端环境下的数字产品的隐蔽性和安全性,在逐渐向“云”端转移的快速响应(Quick Response, QR)码的理论基础上研究并提出了一种QR码双重加密复合数字水印算法,防止QR码“云”端丢失的可能性。对“云”水印图像进行QR码编码生成QR码水印图像,确保水印信息的安全性,再对QR码水印信息实施加密置乱;对“云”上载体Lena图像进行非下采样轮廓波变换(Non-subsampled Contourlet Transform, NSCT),选择储存信息更多的低频部分进行离散小波变换(Discrete Wavelet Transform, DWT),对图像抵抗力较强的低频图像进行奇异值分解(Singular Value Decomposition, SVD),在分解的奇异值中加权加密的QR码水印。通过对算法进行实验验证,该算法在视觉效果较好的前提下,考虑实用性,将复合算法和加密相结合,提高了算法的抵抗力,尤其是旋转攻击和JPEG压缩攻击。

In order to ensure the concealment and security of digital products uploaded to the “cloud” environment, on the basis of the theory of Quick Response(QR)code which is gradually transferred to the “cloud” side, a composite digital watermarking algorithm is studied and proposed to prevent the loss possibility of QR codes on the “cloud” side. First, the watermark image on the “cloud” is executed QR code encoding to generate a QR code watermark image, and then the QR code watermark information is implementted encryption and scrambling to ensure the security of the watermark information. Second, the carrier Lena image on the “cloud” is conducted Non-subsampled Contourlet Transform(NSCT). The low frequency part which stores more information is selected for Discrete Wavelet Transform(DWT). The low-frequency images with strong image resistance is coducted Singular Value Decomposition(SVD). The encrypted QR code watermark is weighted in decomposed singular values.The experimental results show that under the premise of good visual effect, the algorithm which combines the composite algorithm and encryption considering the practicality, improves the resistance of the algorithm, especially the rotation attack and JPEG compression attack.