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 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.

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.

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.

Multi-Secret Sharing Visual Cryptography Scheme Based on XOR Algorithm

2014 ◽  
Vol 644-650 ◽  
pp. 2108-2111 ◽  
Author(s):  
Yan Yan Ha ◽  
Shuai Ji ◽  
Wen Cai He ◽  
Yao Zhang
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Pixel Expansion ◽  
Visual Cryptography Scheme ◽  
Multi Secret Sharing ◽  
Multiple Secret Images

XOR algorithm can be used to improve the recovery effects of visual cryptography scheme. In this paper, we present a multi-secret visual cryptography scheme by using the matrices of the (k, k)-VCS. We can reveal multiple secret images perfectly by the XOR algorithm and shifting operation on the shares. The visual qualities of recovered images are ideal without any pixel expansion.

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 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.

scholarly journals EXTENDING THE VISUAL CRYPTOGRAPHY ALGORITHM USING IMAGE WATERMARKING TECHNIQUE

2013 ◽  
Vol 5 (2) ◽  
pp. 120-123
Author(s):  
Dilip Kumar Kotthapalli ◽  
Dr. V.R. Anitha
Keyword(s):  
Image Watermarking ◽  
Visual Cryptography ◽  
Cover Image ◽  
Secret Sharing Schemes ◽  
Management Problem ◽  
Noisy Image ◽  
Visual Secret Sharing ◽  
Secret Information ◽  
Visual Cryptography Scheme ◽  
Small Image

Visual cryptography is a secret information sharing technique which shares the information in the form of images. It generates noise-like random pixels on share images to hide secret information which on overlay decrypt the information. This technique is known as conventional visual secret sharing schemes. It suffers a management problem, because of which dealers cannot visually identify each share. This problem is solved by the extended visual cryptography scheme (EVCS), which adds a meaningful cover image in each share. While removing the extra cover image it produces extra noise or degrades the hidden image quality. So we propose a new image watermarking technique in this Visual Cryptography Algorithm that places a small image on the noisy image pair at the bottom right corner. So that the cover images need not be removed and it doesn't degrade  resolution of the secret image.

Implementasi Skema Meaningful Sharing pada Kriptografi Visual Berwarna untuk Digital Safe Deposit Box

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Willy Sudiarto Raharjo ◽  
Danny Aguswahyudi
Keyword(s):  
Secret Sharing ◽  
Visual Cryptography ◽  
Human Eye ◽  
Secret Image ◽  
Shared Secret ◽  
Visual Cryptography Scheme ◽  
Index Terms ◽  
Verification Process

Conventional key being used in safe deposit box is a physical key that is easily duplicated, stolen and abused by irresponsible parties. This research proposed a model that substitutes the conventional key with a digital shared secret with the use of visual cryptography scheme. Visual cryptography hide the secret image into two or more images which are called share images that will not reveal anything about secret image if they were separated. The secret image can be recovered simply by stacking the shared images together without any complex computation. In this research, we propose a digital safe deposit box built using a color visual cryptography scheme. The proposed system will generate secret images containing passphrase that will be hidden in two shared images. The shared images are used for substituting the traditional key. We found 93% of the stacked image are visually readable by human eye and Arial-Courier font combination are more readable compared to Times New Roman-Calibri with 95% compared to 92% during human visual verification process. Index Terms— visual cryptography, secret sharing

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