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.

Improved Extended Progressive Visual Cryptography Scheme Using Pixel Harmonization

2021 ◽  
Vol 15 (2) ◽  
pp. 196-216
Author(s):  
Suhas Bhagate ◽  
Prakash J. Kulkarni
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Secret Sharing Schemes ◽  
Pixel Expansion ◽  
Secret Image ◽  
Secret Information ◽  
Meaningful Shares ◽  
Visual Cryptography Scheme

Security of information is of much concern in the modern internet era. Secret sharing schemes provide mechanism of encrypting secret information to prevent illicit usage. Visual cryptography is a secret sharing technique that facilitates encryption of a secret image. Visual cryptography allows us to effectively and efficiently share secrets among a number of trusted parties by hiding secrets within images. These images are encoded into multiple shares as per the rules indicated in basis matrices and later decoded by stacking required number of shares. Progressive visual cryptography has a specialty of recovering secret image as soon as more than one shares received gradually. Existing progressive visual cryptography schemes have severe limitations like data disclose on shares and higher pixel expansion. Improved progressive visual cryptography scheme deals with these limitations. Improved extended progressive visual cryptography scheme solves the issue of management of noise like meaningless shares by creating meaningful shares without any pixel expansion efficiently.

scholarly journals VISUAL CRYPTOGRAPHY FOR COLOR IMAGES

2013 ◽  
pp. 147-149
Author(s):  
ASHWATHIMESANGLA AO
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Color Images ◽  
Secret Sharing Scheme ◽  
Secret Image ◽  
Secret Information ◽  
Host Image ◽  
Sharing Scheme ◽  
Visual Cryptography Scheme

Visual cryptography is a secret sharing scheme for encrypting a secret image, it is a perfectly secure way that allows secret sharing without any cryptographic computation, which is termed as Visual Cryptography Scheme (VCS). In this paper secret image is divided into shares (printed on transparencies), and each share holds some information. At the receiver this shares are merged to obtain the secret information which is revealed without any complex computation. The proposed algorithm is for color host image, divided into three color planes Red, Green, Blue and merged with secret image which is binarized and divided into shares. The decoding requires aligning the result obtained by merging color host image and shares, so as to obtain the secret image.

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.

Cheating Prevention Method in Visual Cryptography by Using Random Grids

2013 ◽  
Vol 416-417 ◽  
pp. 1423-1428
Author(s):  
Hong Wei Lin ◽  
Xue Song Yang ◽  
Shu Wen Wang
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Visual Secret Sharing ◽  
Pixel Expansion ◽  
Random Grids ◽  
Secret Image ◽  
Prevention Method

The traditional cheating prevention is usually based on visual cryptography (VC), in which the constructed image is bigger than the secret image because of the pixel expansion. In this paper, we studied the cheating problems in visual secret sharing (VSS) by random grids (RG) which can prevent the cheating activities with no pixel expansion. We considered the attacks of collusive cheaters who may deviate from the scheme in any way. We presented the cheating method and applied it on attacking existent n-out-of-n VSS scheme based on RG. Then we proposed one cheat-preventing scheme that can prevent the cheating activity upon.

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 A (k, n)-Threshold Progressive Visual Secret Sharing without Expansion

Cryptography ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 28
Author(s):  
Ying-Yu Chen ◽  
Bo-Yuan Huang ◽  
Justie Juan
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Original Image ◽  
Visual Secret Sharing ◽  
Pixel Expansion ◽  
Threshold Secret Sharing ◽  
Secret Image ◽  
Sharing Scheme ◽  
Progressive Visual Secret Sharing ◽  
Positive Integers

Visual cryptography (VC) encrypts a secret image into n shares (transparency). As such, we cannot see any information from any one share, and the original image is decrypted by stacking all of the shares. The general (k, n)-threshold secret sharing scheme (SSS) can similarly encrypt and decrypt the original image by stacking at least k (≤ n) shares. If one stack is fewer than k shares, the secret image is unrecognizable. Another subject is progressive visual secret sharing, which means that when more shares are progressively stacked, the combined share becomes clearer. In this study, we constructed an advanced scheme for (k, n)-threshold SSS that can be encrypted in VC for any positive integers n ≥ k ≥ 2 through the method of combination, and the size of each share is the same as that of the original image. That is, no pixel expansion is required. Our scheme is novel, and the results from the theoretical analysis and simulation reveal that our scheme exhibits favorable contrast to that of other related schemes.

scholarly journals Flip Extended Visual Cryptography for Gray-Scale and Color Cover Images

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 65
Author(s):  
Lu Wang ◽  
Bin Yan ◽  
Hong-Mei Yang ◽  
Jeng-Shyang Pan
Keyword(s):  
Privacy Protection ◽  
Visual Cryptography ◽  
Color Images ◽  
Cover Image ◽  
Error Diffusion ◽  
Gray Scale ◽  
Secret Image ◽  
Transaction Security

Visual cryptography (VC) has found numerous applications in privacy protection, online transaction security, and voting security, etc. To counteract potential cheating attacks, Lin et al. proposed flip visual cryptography in 2010, where a second secret image can be revealed by stacking one share with a flipped version of another share. The second secret image can be designed as an additional verification mechanism. However, Lin’s scheme produces meaningless shares and is only applicable to binary secret images. It is interesting to explore whether it is possible to extend the flip VC to having cover images (i.e., extended VC) and these cover images are color images. This problem is challenging since too many restricting conditions need to be met. In this paper, we designed a flip VC for gray-scale and color cover images based on constraint error diffusion. We show that it is possible to meet all the constraints simultaneously. Compared with existing schemes, our scheme enjoys the following features: Color cover images, no computation needed for decoding, and no interference from cover image on the recovered secret image.

scholarly journals A Novel Image Encryption Using Parity Based Visual Cryptography

2021 ◽  
Vol 26 (1) ◽  
pp. 135-142
Author(s):  
Kanusu Srinivasa Rao ◽  
Mandapati Sridhar
Keyword(s):  
Image Encryption ◽  
Visual Information ◽  
Visual Cryptography ◽  
Least Significant Bit ◽  
Pixel Expansion ◽  
Private Data ◽  
Xor Operation ◽  
Lsb Technique ◽  
Secured Data ◽  
Exclusive Or

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 Exclusive-OR(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.

Sign in / Sign up

Export Citation Format

Share Document