XOR-based Visual Cryptography Research Articles

Security enhancement of an (n, n) threshold non-expansible XOR-based visual cryptography with unique meaningful shares

Security enhancement of an (n, n) threshold non-expansible XOR-based visual cryptography with unique meaningful shares

Sharing Multiple Secrets in XOR-Based Visual Cryptography by Non-Monotonic Threshold Property

Multiple-secret visual cryptography scheme (MVCS) and fully incrementing visual cryptography scheme (FIVCS) have the same functionality that different secrets are gradually revealed by stacking different numbers of shadows. In essence, MVCS and FIVCS are the same. However, both of the two schemes suffer from large pixel expansion and deteriorated reconstructed image quality. In addition, MVCS and FIVCS require intensive computations to create base matrices. In this research, we exploit the capacity of sharing multiple secrets in XOR-based VCS (XVCS). First of all, three efficient base matrix constructions are proposed for realizing the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(k, n)$ </tex-math></inline-formula> non-monotonic XVCS (NXVCS), where the secret image is only revealed by XOR-ing exact <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k$ </tex-math></inline-formula> shadows. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(k, n)$ </tex-math></inline-formula> -NXVCS is adopted to constitute the multiple-secret XVCS (MXVCS). Theoretical analysis on the proposed constructions is provided. Extensive experiments and comparisons are conducted to illustrate that the pixel expansion, the visual quality of recovered image and the efficiency of generating base matrices are significantly improved by the proposed MXVCS, while comparing to MVCS and FIVCS.

XOR-Based Meaningful (n, n) Visual Multi-Secrets Sharing Schemes

The basic visual cryptography (VC) model was proposed by Naor and Shamir in 1994. The secret image is encrypted into pieces, called shares, which can be viewed by collecting and directly stacking these shares. Many related studies were subsequently proposed. The most recent advancement in visual cryptography, XOR-based VC, can address the issue of OR-based VC’s poor image quality of the restored image by lowering hardware costs. Simultaneous sharing of multiple secret images can reduce computational costs, while designing shared images into meaningful unrelated images helps avoid attacks and is easier to manage. Both have been topics of interest to many researchers in recent years. This study suggests ways for XOR-based VCS that simultaneously encrypts several secret images and makes each share separately meaningful. Theoretical analysis and experimental results show that our methods are secure and effective. Compared with previous schemes, our scheme has more capabilities.

XOR-Based (n, n) Visual Cryptography Schemes for Grayscale or Color Images with Meaningful Shares

XOR-based Visual Cryptography Scheme (XOR-based VCS) is a method of secret image sharing. The principle of XOR-based VCS is to encrypt a secret image into several encrypted images, called shares. No information about the secret can be obtained from any of the shares, and after applying the logical XOR operation to stack these shares, the original secret image can be recovered. In this paper, we present a new XOR-based VCS for grayscale or a color secret image. This scheme encrypts the secret grayscale (or color) image into n meaningful grayscale (or color) shares, which can import n difference cover images. After stacking n shares using the XOR operation, the original secret image can be completely restored. Both the theoretical proof and experimental results show that our method is accurate and efficient. To the best of our knowledge, ours is the only scheme that currently provides this functionality for grayscale and color secret images.

A novel perfect contrast XOR-based visual cryptography scheme for multiple secrets

A novel perfect contrast XOR-based visual cryptography scheme for multiple secrets

XOR-based visual cryptography scheme with essential shadows

Visual cryptography scheme with essential shadows (EVCS) is of great significance since it provides different levels of the importance to shadows. In this paper, we propose a general construction method for (t, s, k, n)-VCS with essential shadows based on XOR operation ((t, s, k, n)-EXVCS), which originates from the partition of access structure. The secret image is encrypted into s essential shadows and n-s non-essential shadows. Any k shadows including at least t essentials can cooperate to decode the secret image and the decoding process is implemented by XOR operation on the involved shadows. Our scheme achieves perfectly reconstruction of secret image in the revealed image and the less size of shadows and revealed images. The experiments are conducted to testify the feasibility and practicability of the proposed scheme.

An efficient XOR-based visual cryptography scheme with lossless reconfigurable algorithms

This article proposes an efficient XOR-based visual cryptography scheme with lossless reconfigurable algorithms, which includes an encryption and a decryption schemes for gray-scale and color secret images. The encryption scheme aims to encrypt secret images by mapping them to several shared images that do not suffer any pixel expansion problem and do not reveal any information of the secret images by considering a random column selection algorithm based on the 0-mapping and 1-mapping matrices, where the two matrices are dynamically generated in the encryption scheme. Moreover, the proposed decryption scheme can reconstruct the secret images with only a series of XOR operations. The reconstructed images do not suffer any contrast distortion and pixel expansion problems comparing with their original secret images. Finally, the proposed two schemes are illustrated with the practical examples.

Extended XOR-based visual cryptography schemes by integer linear program

XOR-based visual cryptography scheme (XVCS) is a promising branch of VCS since superior visual quality of recovered secret image is provided. To assist the shadow management, meaningful shadow is preferred. However, existing extended XVCSs (EXVCSs) that generate meaningful shadows are confined to the (n,n) threshold. They are not practical for real-world applications. In this paper, we introduce EXVCS for (k,n) threshold and general access structure (GAS) by using integer linear program (ILP) technique. First of all, an approach for implementing the (k,n)-XVCS is given. We associate the (k,n)-XVCS with a minimizing problem, where the constraints in this problem are derived from the contrast and security conditions in (k,n)-XVCS. The ILP technique is adopted to solve this problem for obtaining the best solutions for constructing the base matrices for (k,n)-XVCS. Further, the construction is extended to (k,n)-EXVCS, in which the shadows with meaningful contents are constructed. To realize complicated sharing strategies, a construction of EXVCS for GAS is described as well. The base matrices for XVCS and EXVCS are demonstrated, as well as the pixel expansion and contrast. Comparisons among related methods are illustrated to show the advantages of the proposed schemes.

(t, k, n) XOR-based visual cryptography scheme with essential shadows

Visual cryptography scheme (VCS) shares a binary secret image into multiple shadows, only qualified set of shadows can reveal the secret image by stacking operation. However, VCS suffers the problems of low visual quality of the revealed image and large shadow size. A (t, k, n) XOR-based visual cryptography scheme (XVCS) shares the secret image into n shadows including t essentials and n-t non-essentials. A qualified set of shadows contains any k shadows including t essentials. The revealing process is implemented by XOR operation on the involved shadows. In this paper, we propose a construction method for (t, k, n)-XVCS with essential shadows. The secret image can be revealed perfectly, and the shadow size is small compared with VCS. Theoretical analysis and experimental results show the security and effectiveness of the proposed scheme.

A Novel XOR-Based Threshold Visual Cryptography with Adjustable Pixel Expansion

A ( k , n ) visual cryptography (VC) scheme encodes a secret image into n shadows that are printed on transparencies distributed among a group of n participants secretly, and reveal the secret image by stacking no less than k of them. Its decryption requires no computation and attracts much attention in image security applications. The pixel expansion and contrast are two important characteristics to evaluate the visual quality of the revealed secret image for a ( k , n ) -VC scheme. The ( k , n ) XOR-based VC (XVC) schemes can greatly improve the visual quality including both pixel expansion and contrast. Previous methods require complex computation and result in high pixel expansion when they are used to construct such schemes. In this paper, we propose a pixel expansion adjustable ( k , n ) -XVC scheme, which allows pixel expansion to be changed among 2 k - 1 - 1 different values. It can ensure each pixel being exactly recovered with the same average contrast no matter it takes any pixel expansion value. The least pixel expansion is much smaller than previous schemes. Our scheme can be easily implemented based on any conventional OR-based ( k , n ) -VC (OVC) scheme.

Image Encryption and Decryption using RSA Algorithm with Share Creation Techniques

visual cryptography system proposed a image encryption and decryption method. In the proposed method Red, Green, Blue color images using visual cryptography. In existing system is working for share created, it is encrypted separately by using visual secret share creation (VSS) algorithms. The proposed work is original images share1 and ahare2 created XOR-Based visual cryptography. This proposed schemes share1 encryption and share2 encryption included in RSA algorithm. The share1 and ahare2 decryption process is enable secret image sharing and then stacking. The proposed system is value calculate the PSNR and MSE formula and then image security using NPCR and UACI formula. The visual cryptography existing work to compare the proposed work and better results quality of RGB color images. The color image encryption and decryption using RSA algorithm and matlab coding.

Perfect recovery of XOR-based visual cryptography scheme

Visual cryptography is an interesting secret sharing scheme, in which participants can observe the secret image by stacking their shares. However, the size expansion and distorted visual effect are two disadvantages of visual cryptography. In this paper, we focus on how to realize the perfect recovery by XOR-ing shares directly. First, we propose the definition of ideal access structure, which is the key point of perfect recovery of XOR-based visual cryptography scheme. The characteristics of ideal access structure are analyzed, and the construction algorithm of shares under ideal access structure is designed. Based on the ideal access structure, a new algorithm is proposed for dividing the general access structure into several ideal access structures, and the secret sharing and recovering algorithms for general access structure are presented. Furthermore, our method can also be utilized in color visual cryptography and multi-secret visual cryptography. The security and perfect recovery of our method have been proved theoretically. Compared with the previous schemes, the proposed scheme realizes the perfect recovery of secret image by XOR-ing shares directly, and the sizes of shares can be decreased efficiently compared with the previous schemes.

Perfect contrast XOR-based visual cryptography schemes via linear algebra

XOR-based visual cryptography scheme (XVCS) was proposed to solve the poor visual quality problem without darkening the background in the reconstructed secret image. However, investigations on XVCS are not sufficient. In this paper, we focus on the traditional model of VCS for general access structures and exploit some extended capabilities for XVCS. Our main contributions are: (1) we put forward constructions of perfect contrast XVCS using the linear algebraic technique without any assumptions such as participants may carry multiple shares or prior information about the shares are to be submitted during the secret reconstruction phase; (2) for some restricted access structures, we achieve perfect contrast and perfect pixel expansion, namely both 1, which is impossible for any OR-based visual cryptography scheme (OVCS); (3) for general access structures, we achieve perfect contrast with smaller pixel expansion compared with many of the results in the literature; (4) Theoretical analysis on the proposed constructions are provided, as well as extensive experimental results and comparisons for demonstrating the effectiveness and advantages of our constructions.

XOR-Based Visual Cryptography

XOR-Based Visual Cryptography

General construction for XOR-based visual cryptography and its extended capability

A visual cryptography scheme (VCS) can be realized by Boolean operations OR and XOR, respectively. The monotone property of OR operation reduces the visual quality of recovered image. To overcome this problem, some advanced XOR based VCSs (VCSXOR) were further designed to provide some favorable features such as high contrast and good resolution. However, they are all confined to non-strong access structures. In this paper, we focus on strong access structures and propose a general construction of VCSXOR, which provides flexible sharing strategies, perfect reconstruction of secret image. Furthermore, a new region incrementing VCS based on XOR (RIVCSXOR) is presented, which exploits the proposed VCSXOR. Experimental results show that our schemes further enrich the application scenarios and outperform previous schemes significantly.

Non-expansible XOR-based visual cryptography scheme with meaningful shares

XOR-based visual cryptography (VC), a brand-new type of VC, is suitable for solving the low image quality and alignment problems in VC system. However, meaningless share and pixel expansion remain to be continuing challenges in existing XOR-based VC. To fix those mentioned defects, XOR-based VC with meaningful shares is introduced in this paper. A basic algorithm implemented by a simple 2n×n matrix for constructing a (n,n) XOR-based VC is first proposed. In the following stage, a (n,n) XOR-based VC with meaningful shares is investigated by adopting the basic algorithm, where the meaningful share can be directly generated without extra process. Extensive experimental results are demonstrated, exhibiting the effectiveness and advantages of the proposed method. Further, sufficient theoretical proofs are provided for illustrating the correctness of the proposed XOR-based VC.

Extended Capabilities for XOR-Based Visual Cryptography

The XOR-based visual cryptography (VC) is a possible methodology to solve the poor visual quality problem without darkening the background in VC. However, investigations on XOR-based VC are not sufficient. In this paper, we exploit some extended capabilities for XOR-based VC. Actually, two XOR-based VC algorithms are proposed, namely XOR-based VC for general access structure (GAS) and adaptive region incrementing XOR-based VC. The first algorithm aims to implement complicated sharing strategy using GAS, while maintaining merits such as perfect reconstruction of secret, no pixel expansion, and no code book requirement. In the second algorithm, the concept of adaptive security level is first introduced, where the security levels are recovered in accordance with the qualified sets instead of the quantity of stacked shares. Adaptive region incrementing XOR-based VC further enriches the application scenarios. Theoretical analysis on the proposed algorithms are provided, as well as extensive experimental results and evaluations for demonstrating the effectiveness and advantages of the two methods.

Property Analysis of XOR-Based Visual Cryptography

A (k,n) visual cryptographic scheme (VCS) encodes a secret image into n shadow images (printed on transparencies) distributed among n participants. When any k participants superimpose their transparencies on an overhead projector (OR operation), the secret image can be visually revealed by a human visual system without computation. However, the monotone property of OR operation degrades the visual quality of reconstructed image for OR-based VCS (OVCS). Accordingly, XOR-based VCS (XVCS), which uses XOR operation for decoding, was proposed to enhance the contrast. In this paper, we investigate the relation between OVCS and XVCS. Our main contribution is to theoretically prove that the basis matrices of (k,n)-OVCS can be used in (k,n)-XVCS. Meantime, the contrast is enhanced 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(k-1)</sup> times.

Modified Visual Cryptography Scheme for Colored Secret Image Sharing

Intent of this paper is to prove the better performance of the XOR Based visual cryptography schemes and traditional VCS on the basis of quality of reconstructed image and type of shares generated for colored images. The visual cryptography scheme (VCS) is a scheme which encodes a secret image into several shares. Here we are working with (2, 2) VCS. XOR-Based visual cryptography is capable to overcome the drawbacks of the visual cryptography scheme (VCS) the small contrast of the recovered secret image.