Research And Application Of QR Code Security Authentication

QR code is easy to be replaced,forged or falsified.Many researchers have studied the QR code authentication mechanism but most algorithls cannot resist the print-cam attack.This thesis proposes three QR code authentication algorithms that resist print-cam attack based on visual cryptography and data hiding technology.The main work of this paper is as follows:(1)QR code security authentication strategies based on Visual Cryptography SchemeThree algorithms based on visual cryptography are proposed.In the first algorithm,the payment QR code is treated as a secret image and its modules are split into two sharing images.Then,these two sharing images are fused with carrier QR codes to generate two encrypted QR codes.One encrypted QR code is placed in the cloud service and the other is placed in the store.The fusion method utilizes the XOR feature of RS(Reed-solomon)code without decreasing the QR code decoding rate.When the encrypted QR code is scanned for authentication,the other encrypted QR code will be downloaded from the server.The original payment QR code will be recovered through the XOR operation.The sharing image of the first algorithm has better concealment.In the second algorithm,the different levels of secret images are split into several sharing images.These images are fused with carrier QR codes to generate encrypted QR codes.The corresponding secret image is obtained after passing different levels of authentication.This algorithm has higher security.In the third algorithm,the secret image is split into n sharing images,and the n sharing images are superimposed to recover the secret image.The secret image can be recoved not only by directly superimposing the QR code(OR operation),but also by using mobile phone reading(XOR operation).(2)A security authentication algorithm for color QR code based on periodic texture patternFirstly,the background image is fused with the conventional QR code through the Positive Base Vector Matrix(PBVM).Color QR codes are generated to better hide information.Secondly,the authentication information is encoded with Hamming code and Gray code,and converted into texture pattern.Finally,this texture pattern is embedded into the color QR code image.Among them,the spatial masking component and background brightness function are combined to make the visual effect better by modifying the JND(Just Noticeable Difference)model.In the authentication procedure,firstly the peak value is calculated by the autocorrelation function of image block.Secondly,the texture direction can be obtained by Hough transformation.Finally,the authentication information is recovered.This algorithm not only is robust to the process of printing and photographing,but also achieves better concealment and visual effect.(3)QR code security authentication algorithm based on(7,4)Hamming codeIn this algorithl,authentication information is embedded in the QR code generation process.Firstly,QR code information is encoded as data module matrix.The data modules in the matrix are grouped.Secondly,the module group is randomly selected by security key and one of the modules is choosed to embed 3-bits authentication information.Finally,the final QR code is generated by masking the module matrix.This algorithm not only resist the attack of printing and photographing,but also has the characteristics of large information embedding capacity.