Application Of Visual Cryptography And Some Research

Two novel schemes for authentication based on VCS are proposed to resist QR code tampering in commerce.Further,an improved scheme is proposed for the research of encryption of multi-secret images.The contributions are as follows:(1)OVCS(OR-based VCS)for mobile payment authenticationWith the purpose of resisting QR code tampering during mobile payment,three algorithems based on OVCS are proposed.In algorithem 1: Firstly,the original QR code is regarded as a secret image.It is split into two shadow images formed by black-and-white modules.That can achieve the effect of blending concealment.Then,shadow images and carrier QR code fuse to generate two secret QR code using the Reed-Solomon characteristics.They are respectively stored in the shop and the server.The fusion method using RS(Reed-solomon)XOR characteristics does not affect the decoding.Finally,two secret QR codes are together stcked(OR operation)to recover the original QR code.In algorithem 2,similar block of the background image is replaced by the shadow with Structural Similarity(SSIM).It makes the shadow more concealed in the background image.There are better visual effects.In algorithem 3,the background image in algorithm 2 is replaced by the color image.The fused QR code is generated based on error correction mechanism.The locations of the shadow in the color image are alternative.This algorithem makes the shadow more hidden and has better visual effects.It reduces the attack and more secure.(2)XVCS(XOR-based VCS)for bike-shared service authenticationIn the authentication,there are some problems.They are both limited size of the secret and low contrast of recoverd image.In order to solve problems,two XVCS algorithms are proposed.In algorithm 1: Firstly,the secret QR code is generated based on error correction mechanism of QR code.It is as the first shadow image and stored on the bike-share.That can greatly reduces the probability of being attacked compared with the meaningless shadow image.Then,based on the improved(2,2)-XVCS,the second shadow image is obtained and stored on the server.The secret QR code is used for authentication to obtain the shadow image on the server.They are together stacked(XOR operation)to recover secret image.XOR operation makes the image contrast greatly improved.In algorithm 2,the secret QR code based on XOR'ed characteristic of RS code is generated.Compared with meaningless shadow,the secret QR code as the meaningful shadow can reduce suscessful tempering.And the size of the secret image is larger.(3)MVCS(Multi-secret VCS)using ringed shadowAgainst problems of large pixel expansion and the poor recovered image in the previous MVCS,an improved MVCS is proposed.A ring shadow is generated at random.Another ring shadow is generated based on the rotation.The various secrets are recovered by rotating and stacking.New scheme does not have pixel expansion and the recovered image contrast is higher.