Visual cryptography

About: Visual cryptography is a research topic. Over the lifetime, 1724 publications have been published within this topic receiving 25300 citations.

Secure QR Code Scheme Based on Visual Cryptography

Abstract: With the wide application of QR code, the security problem of QR code is serious, such as information leakage and data tampering. In order to solve the QR information security problem, this paper proposed a secure QR code schema based on visual cryptography. The QR code is divided into two share images that can be transmitted separately. The generation of the two share images is based on the pseudo-random matrix, that is, the pixels in the two share images are determined by the corresponding values in the pseudo-random matrix. The two share images can be stacked simply to restore the information. Simulation results show that the QR code image can be well hidden, and it can be restored effectively. Keywords-QR code; visual cryptography; secret sharing; pseudo-random modulation

Watermarking video content using visual cryptography and scene averaged image

Abstract: With the increasing convergence of network, services, and devices, more number of end user devices are accessing digital media content which were hitherto accessible mainly from computers and television sets. This makes the digital media more prone to illegal copying and distribution. In this paper, we propose a robust digital video watermarking scheme for copyright protection using the principles of visual cryptography, scene change detection in videos, and conversion of each scene into an image by averaging the frames in the scene. In the proposed method, data is extracted and stored as one share of the watermark pattern instead of embedding data into the original video as in the conventional watermarking schemes. Since no data is embedded, the method is robust against watermark attacks aimed at detecting and destroying or distorting data embedded into videos. Simulation results show that the method is robust even in the case of 50% frame drop. All the watermarked scenes, not frames, need to be dropped for an effective attack against the watermark. Dropping of scenes makes the video less attractive for illegal copying and distribution.

On the equivalence of two definitions of visual cryptography scheme

Abstract: A visual cryptography scheme (VCS) is a secret sharing method, for which the secret can be decoded by human eyes without needing any cryptography knowledge nor any computation. To the best of our knowledge, there are two different definitions of basis matrix (k,n)-VCS. The definition of unconditional secure basis matrix (k,n)-VCS is the generally accepted one, and has been widely used since the pioneer work of Naor and Shamir in 1994, while the definition of stacking secure basis matrix (k,n)-VCS is relatively new, and has been used in many studies in recent years. Our study shows that the above two definitions are actually equivalent. Furthermore, we generalize the equivalence relation to general access structure basis matrix VCS and general access structure size invariant VCS. But the equivalence relation does not hold for non-basis matrix (k,n)-VCS.

A technique for sharing a secret color image

Abstract: The present invention is related with ""Information Security"". A color image hiding technique developed based on Visual Cryptography is hereby proposed. The technique can very effectively hide a secret color image between any two randomly selected color images having certain significance. In other words, the two color images are used to camouflage the secret image and, therefore, may individually be owned by two participants sharing the secret. When the secret image needs to be restored, the two participants need only to provide each of the camouflaging image them possesses before. By means of simple overlapping and rather simple calculations, the secret image can be restored from the two camouflaging images. The present invention has a high security. It is impossible to restore the secret image if any one of the camouflaging images is not available. Note: The present invention is in the area of ""Information Security"". The related professional advise or assistance may be obtained from ""Information Security Society of the Republic of China"".