Visual cryptography

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

An image zero-watermarking scheme based on visual cryptography utilizing contour-wavelet

Abstract: To achieve the copyright protection of digital image,a zero-watermarking scheme based on visual cryptography(VC) is proposed.Firstly,a novel multiscale geometric analysis(MGA): contour-wavelet transform(CWT) is implemented;then in the transform domain,the coefficients are selected properly from the mid-subband which has the largest energy;finally,the zero-watermark signal is constructed by concealing the binary watermark into two shares according to the selected coefficients and a predefined VC codebook.The experimental results show the proposed scheme protects the copyright of digital image without modifying the host image,and it has quite robust against common image processing attacks such as JPEG compression,cropping,noise adding,sharpening and rotation.

Implementation K out of N visual cryptography using K out of K scheme

Abstract: Visual cryptography is a method to protect image-based secrets having less computation decoding process. In this technique, number of parts is generated from one image. The parts are sent to the destination and the original image is constructed by stacking all the share images. Different parts are generated for different types of images (binary, gray and color). Naor and Shamir introduced K out of K visual cryptography scheme which is a well known visual cryptography algorithm. In this study K out of N visual Cryptography (by permutation) is implemented using K out of K scheme. Experimental result shows the effectiveness of the approach.

A novel technique of visual cryptography for maintaining the security of visual information transaction

Abstract: As the growth in the technology increases maintaining the security of visual information during its transaction has to be increased. Rapid growth in the techniques for doing so is also increasing. Internet has become most commonly used media for communication and hence text, voice, video, Images and many more are transmitted through Internet. These might include Military Secrets, Commercial Secrets and Information of individuals and therefore it has to be transmitted by safer means with enhanced security. In the process of Visual Cryptography a secret image is encrypted into shares which refuse to divulge information about the original secret image. In this paper, Chaotic Pseudo - Random Number generation, Zigzag Scan Pattern Method, Method to reduce the degradation of the resultant image is proposed by an extension from gray to color image. Pixel Index Method is discussed to improve the security for images.

Involutory matrix in visual cryptography

Abstract: In Hill cipher encryption, the complexity of finding the inverse of the matrix during decryption is eliminated by adopting self invertible matrices. Authentication of hall tickets for candidates during examination is a complicated issue. By evaluating simultaneously encryption and decryption with details of text, photos and signatures of candidates it is easy to prevent malpractices during examination held at various centres of the institution.

Revisiting the False Acceptance Rate Attack on Biometric Visual Cryptographic Schemes

Abstract: Visual cryptography is an increasingly popular cryptographic technique which allows for secret sharing and encryption of sensitive data. This method has been extended and applied to secure biometric data in various protocols. In this paper, we propose a general framework to help assess the security of these extended biometric visual cryptographic schemes (e-BVC). First, we formalize the notion of “perfect resistance against false authentication” under our framework and show that our formalization captures the traditional false acceptance attack under plausible assumptions. Second, we modify the traditional false acceptance attack and propose a new and generic strategy for attacking e-BVC schemes. As an application, we present a case analysis for a recent implementation of a face recognition protocol and verify the practical impact of our proposed framework and attack in detail.