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

2020 ◽  
Vol 10 (4) ◽  
pp. 1321
Author(s):  
Yusheng Guo ◽  
Xingxing Jia ◽  
Qimeng Chu ◽  
Daoshun Wang
Keyword(s):  
Visual Cryptography ◽  
Visual Quality ◽  
Pixel Expansion ◽  
Image Security ◽  
Secret Image ◽  
Security Applications ◽  
Average Contrast

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.

scholarly journals Collusion Attacks in XOR Based RG-VSS

2019 ◽  
Vol 8 (10) ◽  
pp. 2339-2345
Keyword(s):  
Secret Sharing ◽  
Data Security ◽  
Visual Cryptography ◽  
Visual Quality ◽  
Visual Secret Sharing ◽  
Security Issue ◽  
Collusion Attacks ◽  
Secret Image ◽  
The Past

Visual secret sharing (VSS) is a well-known technique from the past few decades for data security. Recently, XOR based VSS has attracted many researchers due to its lossless or good visual quality of reconstructed secret image. Cheating in visual cryptography based VSS was introduced by Horng et. al. in 2006. Cheating occurs when a dishonest participant presents fake share and performs stacking of fake share with honest participants who have genuine share, thereby revealing the fake secret image instead of the original secret image. Cheating occurs when some XOR based VSS are exposed to collusion attacks. Here, in this paper, we have demonstrated and proved that there is a security issue in existing XOR based VSS schemes.

An Improved Size Invariant (n, n) Extended Visual Cryptography Scheme

2016 ◽  
Vol 12 (2) ◽  
pp. 80-88 ◽  
Author(s):  
Rahul Sharma ◽  
Nitesh Kumar Agrawal ◽  
Ayush Khare ◽  
Arup Kumar Pal
Keyword(s):  
Visual Cryptography ◽  
Visual Quality ◽  
Binary Image ◽  
Secret Message ◽  
Grayscale Image ◽  
Secret Image ◽  
Meaningful Shares ◽  
Connectivity Property ◽  
Visual Cryptography Scheme

In this paper, the authors have presented a (n, n) extended visual cryptography scheme where n numbers of meaningful shares furnish a visually secret message. Initially they have converted a grayscale image into binary image using dithering method. Afterwards, they have incorporated pixel's eight neighboring connectivity property of secret image during formation of meaningful shares. The scheme is able to generate the shares without extending its size. This approach has enhanced the visual quality of the recovered secret image from n numbers of shares. The scheme has been tested with some images and satisfactory results are achieved. The scheme has improved the contrast of the recovered secret image than a related (n, n) extended visual cryptography scheme.

scholarly journals An optimization of color halftone visual cryptography scheme based on Bat algorithm

2021 ◽  
Vol 30 (1) ◽  
pp. 816-835
Author(s):  
Firas Mohammed Aswad ◽  
Ihsan Salman ◽  
Salama A. Mostafa
Keyword(s):  
Visual Information ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Visual Cryptography ◽  
Visual Quality ◽  
Bat Algorithm ◽  
Pixel Expansion ◽  
Low Contrast ◽  
Secret Image ◽  
Visual Cryptography Scheme

Abstract Visual cryptography is a cryptographic technique that allows visual information to be encrypted so that the human optical system can perform the decryption without any cryptographic computation. The halftone visual cryptography scheme (HVCS) is a type of visual cryptography (VC) that encodes the secret image into halftone images to produce secure and meaningful shares. However, the HVC scheme has many unsolved problems, such as pixel expansion, low contrast, cross-interference problem, and difficulty in managing share images. This article aims to enhance the visual quality and avoid the problems of cross-interference and pixel expansion of the share images. It introduces a novel optimization of color halftone visual cryptography (OCHVC) scheme by using two proposed techniques: hash codebook and construction techniques. The new techniques distribute the information pixels of a secret image into a halftone cover image randomly based on a bat optimization algorithm. The results show that these techniques have enhanced security levels and make the proposed OCHVC scheme more robust against different attacks. The OCHVC scheme achieves mean squared error (MSE) of 95.0%, peak signal-to-noise ratio (PSNR) of 28.3%, normalized cross correlation (NCC) of 99.4%, and universal quality index (UQI) of 99.3% on average for the six shares. Subsequently, the experiment results based on image quality metrics show improvement in size, visual quality, and security for retrieved secret images and meaningful share images of the OCHVC scheme. Comparing the proposed OCHVC with some related works shows that the OCHVC scheme is more effective and secure.

scholarly journals An Improved Size Invariant (n, n) Extended Visual Cryptography Scheme

Cryptography ◽  
2020 ◽  
pp. 449-457
Author(s):  
Rahul Sharma ◽  
Nitesh Kumar Agrawal ◽  
Ayush Khare ◽  
Arup Kumar Pal
Keyword(s):  
Visual Cryptography ◽  
Visual Quality ◽  
Binary Image ◽  
Secret Message ◽  
Grayscale Image ◽  
Secret Image ◽  
Meaningful Shares ◽  
Connectivity Property ◽  
Visual Cryptography Scheme

In this paper, the authors have presented a (n, n) extended visual cryptography scheme where n numbers of meaningful shares furnish a visually secret message. Initially they have converted a grayscale image into binary image using dithering method. Afterwards, they have incorporated pixel's eight neighboring connectivity property of secret image during formation of meaningful shares. The scheme is able to generate the shares without extending its size. This approach has enhanced the visual quality of the recovered secret image from n numbers of shares. The scheme has been tested with some images and satisfactory results are achieved. The scheme has improved the contrast of the recovered secret image than a related (n, n) extended visual cryptography scheme.

K out of N Secret Sharing Scheme for Multiple Color Images with Steganography and Authentication

2016 ◽  
Vol 16 (02) ◽  
pp. 1650010 ◽  
Author(s):  
P. Mohamed Fathimal ◽  
P. Arockia Jansi Rani
Keyword(s):  
Secret Sharing ◽  
Visual Quality ◽  
Color Images ◽  
Pixel Expansion ◽  
Image Sharing ◽  
Digital Ecosystem ◽  
Sharing Scheme ◽  
Text Steganography ◽  
Key Aspects

With our lives trundling toward a fully-digital ecosystem in break-neck speed, today’s encryption and cryptography are facing the challenge of ensuring security and future-readiness of our transactions. When such transactions involve multiple hands, transmission of such data in discrete and recoverable parts (secret shares) guarantees confidentiality. This paper’s objective is to present a foolproof way of multiple secret sharing, eliminating issues such as half-toning and degradation of visual quality of the recovered images. This [Formula: see text] out of [Formula: see text] steganography and authenticated image sharing (SAIS) scheme for multiple color images generates [Formula: see text] relevant shares with the ability to reconstruct the secret images using [Formula: see text] shares and facility to find out any move for appropriation of share cover images. The key aspects of this proposed scheme is to use simple Boolean and arithmetic operations with reduction of computational complexity from [Formula: see text] to [Formula: see text] and to share multiple images without any pixel expansion.

Chaotic Map for Securing Digital Content

2016 ◽  
Vol 3 (1) ◽  
pp. 20-35 ◽  
Author(s):  
Dhiraj Pandey ◽  
U. S. Rawat
Keyword(s):  
Secret Sharing ◽  
Chaotic Map ◽  
Logistic Map ◽  
Visual Cryptography ◽  
Visual Quality ◽  
Digital Content ◽  
Digital Information ◽  
Pixel Expansion ◽  
Empirical Results ◽  
Logistic Chaotic Map

Progressive Visual Cryptography (PVC) is quite suitable for sharing sensitive digital data.Previous research on PVC, such as Fang et al. (2006) and W.P.Fang et al.(2008) were all carrying pixel-expansion problem and also gives a poor visual quality on the recovered stacked image. Recently, Hou&Quan (2011) have developed a progressive scheme for secret sharing. It is observed that shares generated by the scheme are free from pixel expansion problem, but shares are not fully secure. In this paper, a new progressive sharing algorithm based on logistic chaotic map has been proposed to overcome the said limitation of Hou (2011) scheme. The irregular outputs of the logistic map are used to encode a secret digital information carrying image. The performance of the algorithm in the scheme of Hou (2011) is critically analyzed and compared with new suggested scheme. Empirical results are presented to showcase the performance of the authors' proposed scheme in terms of its effectiveness (imperceptibility and security) and feasibility.

scholarly journals Meaningful Secret Image Sharing Scheme with High Visual Quality Based on Natural Steganography

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1452
Author(s):  
Yuyuan Sun ◽  
Yuliang Lu ◽  
Jinrui Chen ◽  
Weiming Zhang ◽  
Xuehu Yan
Keyword(s):  
Visual Quality ◽  
Secret Image Sharing ◽  
Secret Image ◽  
Image Sharing ◽  
Lossless Recovery ◽  
Sharing Scheme ◽  
Image Protection ◽  
Embedding Rate ◽  
Secret Image Sharing Scheme

The (k,n)-threshold Secret Image Sharing scheme (SISS) is a solution to image protection. However, the shadow images generated by traditional SISS are noise-like, easily arousing deep suspicions, so that it is significant to generate meaningful shadow images. One solution is to embed the shadow images into meaningful natural images and visual quality should be considered first. Limited by embedding rate, the existing schemes have made concessions in size and visual quality of shadow images, and few of them take the ability of anti-steganalysis into consideration. In this paper, a meaningful SISS that is based on Natural Steganography (MSISS-NS) is proposed. The secret image is firstly divided into n small-sized shadow images with Chinese Reminder Theorem, which are then embedded into RAW images to simulate the images with higher ISO parameters with NS. In MSISS-NS, the visual quality of shadow images is improved significantly. Additionally, as the payload of cover images with NS is larger than the size of small-sized shadow images, the scheme performs well not only in visual camouflage, but also in other aspects, like lossless recovery, no pixel expansion, and resisting steganalysis.

scholarly journals Visual Cryptography Using Binary Amplitude-Only Holograms [Invited]

2022 ◽  
Vol 2 ◽  
Author(s):  
Lina Zhou ◽  
Yin Xiao ◽  
Zilan Pan ◽  
Yonggui Cao ◽  
Wen Chen
Keyword(s):  
Visual Cryptography ◽  
Human Vision ◽  
Pixel Expansion ◽  
Secret Image ◽  
Secret Information

Visual cryptography (VC) is developed to be a promising approach to encoding secret information using pixel expansion rules. The useful information can be directly rendered based on human vision without the usage of decryption algorithms. However, many VC schemes cannot withstand occlusion attacks. In this paper, a new VC scheme is proposed using binary amplitude-only holograms (AOHs) generated by a modified Gerchberg-Saxton algorithm (MGSA). During the encryption, a secret image is divided into a group of unrecognizable and mutually-unrelated shares, and then the generated shares are further converted to binary AOHs using the MGSA. During image extraction, binary AOHs are logically superimposed to form a stacked hologram, and then the secret image can be extracted from the stacked hologram. Different from conventional VC schemes, the proposed VC scheme converts a secret image into binary AOHs. Due to the redundancy of the generated binary AOHs, the proposed method is numerically and experimentally verified to be feasible and effective, and possesses high robustness against occlusion attacks.

scholarly journals Secure Secret Image Sharing Using Histogram Localization Based Block wise Methodology

2019 ◽  
Vol 8 (2) ◽  
pp. 186-191
Keyword(s):  
Data Security ◽  
Vision System ◽  
Visual Cryptography ◽  
Human Vision ◽  
Human Vision System ◽  
Image Size ◽  
Pixel Expansion ◽  
Secret Image ◽  
Image Sharing ◽  
Innovative Method

Various types of encryption techniques have been used for data security. Complex algorithms are followed for this purpose in most of the methods. Confidentiality is provided by a technique called visual cryptography excluding of any intricate computations and algorithms. In this paper, we put forward an innovative method called Histogram Localization based Blockwise (HLB) approach to solve pixel expansion problem at the same time it will increase the security and visual quality for highly confidential secret image which is in color. According to this method, the secret shares are generated based on the histogram and also the number of black pixels in the corresponding block. The image size of resultant shares is same as in the original secret image. These shares are distributed to participants, and human vision system is used for decryption purpose.

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