Visual cryptography

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

A Novel Image Encryption Using Parity Based Visual Cryptography

Abstract: Received: 13 November 2020 Accepted: 29 January 2021 The current era is mainly focused on secured data transmission and every organization takes preventive measures to protect network’s private data. Among different techniques visual cryptography is a prominent one that that encrypts the visual information and decrypts secret using mechanical operations without any computation, but each share need pixel expansion. In the current work, we propose an Image encryption technique using (n, n) Visual cryptography based on simple operations without pixel expansion. The proposed novel technique gives an image encryption using visual cryptography based on Least significant bit (LSB) technique in spatial domain and parity mechanism using ExclusiveOR(XOR) operation. developed for encrypting grey scale image. Image encryption and decryption uses simple Boolean operations. The technique provides better quality of shares and recovers without any loss.

A Probabilistic Essential Visual Cryptographic Scheme for Plural Secret Images

Abstract: In order to reduce the pixel expansion of visual cryptography scheme (VCS), many probabilistic schemes were proposed. Let P = {P 1,P 2,P 3,...,P n } be the set of participants. The minimal qualified set for essential VCS is given by Γ0={A: A ⊆ P, P 1 ∈ A and |A| = k}. In this paper we propose a construction of probabilistic essential VCS for sharing plural secret images simultaneously.

A New Bayer Matrix-based Scheme of Visual Cryptography for Grey Level Images

Abstract: A visual cryptography scheme for a set P of n participants is a method to encode a secret image into n shadow images called shares, where each participant in set P receives one share. The advantage is that the participants in a qualified set will be able to see the secret image without any knowledge of cryptography and without performing any cryptographic computation. The decoding operation is simple, safe and secure. Its efficacious for secret sharing, whereas visual cryptography scheme for Grey Level Images has its shortcomings: the pixel expansion makes the size of the share transparencies very big. In this paper a new Bayer matrix based scheme of Visual cryptography for grey level images is applied.

Multiple image sharing based on colour visual cryptography

Abstract: Traditional visual cryptography is mainly used to hide one secret message in two or more black and white images called share images. The secret message can be revealed by stacking the share images without any computation. Visual cryptography is safe because secret messages cannot be revealed by one of the share images. Traditional visual cryptography is impractical though, as secret messages are always black-and-white text or simple images. Recently, many researchers have used grey-level images or colour images for secret messages that can be much more complex. Furthermore, these complex and large secret messages can be protected employing visual cryptography. This paper presents a new method of producing multicoloured share images based on visual cryptography. A horizontal rotation is employed to reveal a second secret colour message. This proposed method can create share multicoloured secret messages and, moreover, provide safety.

Cheating Immune Visual Cryptographic Scheme with Reduced Pixel Expansion

Abstract: One of the drawbacks in visual cryptography is cheating attacks, where the malicious adversaries can cheat the honest participant by submitting fake shares during reconstruction phase. Cheating immune visual cryptographic schemes are used for mitigating cheating attacks in visual cryptography. There are two types of cheating immune schemes: One is share authentication-based schemes, and the other is blind authentication-based schemes. For the existing blind authentication-based schemes, the pixel expansion value will increase in the order of O(n). In this paper, a blind authentication-based cheating immune visual cryptographic scheme is proposed by modifying the existing scheme based on uniform codes where the pixel expansion value will increase in the order of O(log n).