A two-dimensional code security authentication method based on digital watermarking

A security authentication method of QR code based on digital watermarking is proposed to improve the security of two-dimensional code. This method can be applied to verify the authenticity of QR code. Firstly, the host image is partitioned into blocks and then the Two-dimensional Discrete Cosine Transform(2D-DCT) is applied for each block. Secondly, a smaller block is selected from each block in the process above, and then the Singular Value Decomposition (SVD) is applied for the smaller block. At last, the 2D-DCT and SVD transforms are applied for the image of watermark, after that the watermark is embedded by modifying the characteristic value of the SVD. The process of extracting watermark image is opposite to the process of embedding watermark. Computer simulation and experimental results prove this method has the characteristics of strong robustness, invisibility, high security and low computational cost.