Research On Electronic Document Anti-counterfeiting Technology Based On QR Code And Seal Watermark

Certificates are documents used by people to prove their identities and experiences,and their importance is self-evident.Their importance is self-evident.Nowadays,with the rapid development of computer technology,these documents have gradually become electronic and networked.This change makes people's lives and work more convenient.At the same time,it also provides criminals with forged and tampered documents to some extent opportunity.Therefore,the protection of electronic certificates is urgent.The seal is a credible stationery on the certificate,which means identification or signature.However,due to the single color and simple structure,the stamp image is easy to be forged.In recent years,two-dimensional code technology has been widely used in the field of anti-counterfeiting.It is a bar code technology with natural anti-counterfeiting function,but the encoding is open,so its anti-counterfeiting performance is not high.Digital watermarking technology is an information hiding technology that can effectively protect the copyright of digital products.Therefore,the combination of digital watermark technology,seal image and two-dimensional code technology in the field of anti-counterfeiting can greatly improve the anti-counterfeiting performance and provide strong protection for the anti-counterfeiting of electronic documents.In order to enable the effective protection of electronic documents,this paper studies the characteristics of electronic documents,the characteristics of seal images and the characteristics of two-dimensional code images.Combined with digital watermarking technology,an anti-counterfeiting technology for electronic documents based on QR codes and seal watermarks is proposed.First,a binary image watermarking algorithm is proposed based on the characteristics of QR code images.This algorithm uses QR code(PNG image)as the carrier image,and uses MD5(Message-Digest Algorithm 5)algorithm to encode the core information of the file,and the encoding result is used as the watermark information.Combining the characteristics of the binary image and the structural characteristics of the QR code,the pixel values of the QR code image are read into a one-dimensional sequence by column,and then a two-dimensional hyperchaotic map is used to generate a position sequence.The watermark information is used to replace the one-dimensional sequence of the image according to the position sequence,and the watermark is embedded in the spatial domain.Secondly,a watermarking algorithm based on the seal image is proposed.The algorithm divides the seal image(PNG image)into three layers of R,G,and B,and extracts the transparent channel alpha of the image.The R layer and alpha are used as carriers,the file information is used as watermark information,and segmentation is performed according to a certain step.The discrete cosine watermarking algorithm and the LSB spatial watermarking algorithm are respectively embedded in the R layer and the alpha to complete the information hiding.Finally,the paper proposes a step-by-step anti-counterfeiting scheme.By comparing the QR code decoded information with the credential information,the extracted QR code watermark information and the information obtained by applying the MD5 algorithm again,and the extracted seal image watermark information and credential information,a three-step anti-counterfeit verification is achieved.It should be noted that the authenticity of the certificate can be proved if and only if the three-step anti-counterfeit verification is passed.The experimental results show that the space watermarking algorithm based on QR code and the watermarking algorithm based on seal image have good resistance to common attacks such as salt and pepper noise and Gaussian noise.When the parameter values of salt and pepper noise and Gaussian noise reach 0.05 and 0.1,the QR code can still be decoded normally,and the NC values are greater than 0.94.When the parameter values of salt and pepper noise and Gaussian noise reach 0.01 and 0.005,the PSNR of the stamp image is greater than 44 and the NC values are greater than 0.97.It shows that the two algorithms have good invisibility and strong robustness.The electronic certificate anti-counterfeiting authentication scheme based on QR.code and seal image proposed in this paper can identify general tampering and forgery,and can effectively implement the electronic certificate anti-counterfeiting authentication.