Visual cryptography

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

The image multiple secret sharing schemes without pixel expansion

Abstract: In this paper, two secret sharing schemes were proposed. The two schemes both have the characteristic that the share images they produced are with no pixel expansion. In encoding phase, the rotated share scheme creates two share images for hiding three secret images, whereas the Exclusive OR rotated scheme achieve three share images for hiding four secret images. In decoding phase, the first scheme get secret information by stacking images and rotating image with different angles (0°, 90°, 180°). The second scheme get secret information by doing XOR operation, stacking, and rotating image with different angles (0°, 90°, 180°, 270°). Compare with other schemes of Visual Cryptography, our schemes not only increase the quantity of secret information, but also enhance quality of share image without increasing embed data.

On the difficulty of aligning VSS random grids

Abstract: Visual secret sharing (VSS) schemes are classified into two categories-visual cryptography-based (VC) and random grid-based (RG)-with the purpose of encoding a secret into several meaningless shared images that can be superimposed to reveal the secret again. VC-based VSS suffers from the problems of pixel expansion and difficulty in alignment. Although the first problem has been solved by RG-based VSS, the latter remains. This paper proposes a new deviation-tolerant RG-based VSS method without pixel expansion. To demonstrate its feasibility, experiments are conducted to show that the reconstructed secret image is still recognizable visually when one shared image shifts by one or more pixels. Compared with related works, the proposed scheme not only has higher misalignment tolerance but also avoids the significant drawbacks in the related work. Recover the secret image without the need to align the shares precisely.A deviation-tolerant RG-based VSS method without pixel expansion.The proposed scheme has higher misalignment tolerance.

A new visual cryptography scheme for STS based access structures

Abstract: Visual Cryptography Scheme (VCS) for general access structure was developed by Ateniese, Blundo, Santis and Stinson in 1996 for black and white image and subsequently different schemes have been developed. In this paper, we propose a new model for Steiner Triple Systems (STS) based access structures by using “stacking” i.e. “superimposition” and “machine operation” which are mathematically equivalent to “OR” and “XOR” respectively. The concept of qualified set is extended. The technique to construct the VCS is developed for the model. The structure of the VCS is analysed. The contrast of the reconstructed secret image (SI) under the two operations is studied. Finally we introduce STS based (3, n)-Visual Threshold Scheme (VTS) and derive the ratio of its pixel expansion and the number of qualified sets.

A novel visual cryptography scheme based on substitution cipher

Abstract: Security of information communication through open channels has been the prime concern during the last few decades Apart from many conventional cryptographic schemes, visual cryptographic techniques have also been in use for data and information security Visual Cryptography is basically a cryptographic method in which decryption is performed by human visual system In this paper, we present a novel visual cryptography scheme based on a substitution cipher and random grid The scheme uses two-fold encryption In the first fold of encryption, Caeser cipher is used to encrypt the image row wise and then column wise using a key of the size equal to the greatest common devisor of the number of rows and columns in the secret image Then a random matrix is generated and the transformed secret image is XORed with this random matrix to enhance the security The scheme is shown to be secure and decryption is also lossless

The Secured Anti Phishing Approach Using Image Based Validation

Abstract: Anti-phishing schemes in the websites presently work on helping users to confirm whether a web site is honest or not. Phishing on the web pages is an attempt by an individual or a group to threats/hackers seeking to retrieve an individual’s personal private information such as passwords, usernames/confidential information, credit card information etc. In this paper, I am proposing a new approach named as “The secured anti phishing approach using image based validation" to solve the problem of phishing. Textual keyword validation along with visual cryptography is a key advantage of this paper. The original image is divided into many blocks and rearrangement can be done. The use of visual cryptography technique((2,2) VCS scheme) is explored to reserve the privacy of image by degenerating the original image into two dissimilar image shares by manipulating the black and white pixel value of the image . Part of the image share will be stored in the servers such that the original image can be revealed only when both (client, server) of the shares are concurrently available. The individual share images do not reveal the identity of the original image . After the original image is revealed later merging different shares, which can be used as the password. Dynamically generating the image by the system is one of the major advantages of the system.