Visual Secret Sharing Scheme Research Articles

Novel robust zero-watermarking scheme for digital rights management of 3D videos

Digital watermarking is an effective technique for the digital rights management (DRM) of three-dimensional (3D) videos, which is still a crucial issue in the field of 3D televisions. The current watermarking schemes for 3D videos can be classified into two main categories: One embeds watermarks into 2D video frames, and the other embeds watermarks into depth maps. The former causes irreversible distortions to synthesized 3D videos whereas the latter is insufficiently robust against some of normal video attacks. Moreover, because these watermarking schemes only embed watermarks into either 2D video frames or depth maps of 3D videos, none of them can protect the copyrights of these two parts simultaneously and independently. To address those problems, a novel robust zero-watermarking scheme for the DRM of 3D videos is proposed in this study. In the proposed scheme, master shares are first generated by extracting features from temporally informative representative images (TIRIs) of both the 2D video frames and depth maps. Then, ownership shares, which denote the relationships between copyright information and master shares, are generated based on the Visual Secret Sharing (VSS) scheme and stored for copyright identification. Finally, copyright ownerships are identified by stacking master shares and ownership shares. The experiment results demonstrate that the proposed scheme outperforms the current state-of-the-art watermarking schemes because it does not cause any distortion to the synthesized 3D videos, exhibits strong robustness against various video attacks, and protects the copyrights of 2D video frames and depth maps of 3D videos simultaneously and independently.

(n, n+1) Visual Secret Sharing Scheme Based on Local Binary Pattern Operator

A novel (n,n+1) Visual Secret Sharing (VSS) Scheme based on Local Binary Pattern (LBP) operators was presented in this paper. The proposed schemes without adopting Boolean operations make full use of the local contrast features of LBP operators to conceal secret image data into different image shares, which can then be used to recover the secret easily and exactly through the computation of LBP operators. Compared with state-of-the-art algorithms, experiments show that our proposed schemes demonstrate good randomness in shares and exact determination in reconstruction process without much computational cost.

Progressive visual secret sharing for general access structure with multiple decryptions

Visual secret sharing (VSS) for general access structure (GAS) owns wider applications than (k, n) threshold VSS. VSS with multiple decryptions realizes the functionalities of both OR-based VSS (OVSS) and XOR-based VSS (XVSS), which can broaden the applications as well compared to one recovery method-based VSS. In this paper, we propose a progressive VSS (PVSS) scheme for GAS with the features of both OR and XOR decryptions based on random grid (RG). The different regions of the secret image and corresponding genearted random bits are employed to gain progressive property as well as GAS with OR and XOR decryptions. For the qualified sets, if we have a copy machine, we can reconstruct the secret by stacking. On the other hand, if a device with XOR operation is available, we can improve the visual quality of the recovered secret image as well as we can reconstruct the secret image losslessly when we collect all the n shares. In addition, our scheme has neither pixel expansion nor codebook design due to RG. The effectiveness of the proposed scheme are shown in terms of experimental results and analyses.

Participants increasing for threshold random grids-based visual secret sharing

In (k, n) visual secret sharing (VSS), a secret image is generated into n shadow images printed onto transparencies and distributed to n associated participants. The secret image can be recovered by stacking any k or more shadow images and human visual system without cryptographic computation. The previous VSS schemes neglected participants increasing. However, in some applications, some new shadow images need to be generated because some new participants join the secret sharing. In this paper, we consider the new participants increasing issue as well as propose a participants increasing method only from the n original shadow images generated by previous existed (k, n) threshold random grids-based visual secret sharing (RGVSS). Without knowing the original generation algorithm and the original secret image, q new shadow images can be obtained from the original n shadow images without reprinting the original ones, as a result $$(k, n+q)$$ threshold RGVSS will be gained. Theoretical analysis and experiments are conducted to evaluate the security and efficiency of the proposed scheme.

Novel basis matrix creation and preprocessing algorithms for friendly progressive visual secret sharing with space-efficient shares

The traditional k out of n Visual Secret Sharing (VSS) scheme encodes a secret binary image into n shares of random pattern. If the shares are printed onto transparencies, the secret image can be visually revealed only when a subset of k or more transparencies are stacked together otherwise nothing will be revealed. Progressive Visual Secret Sharing (PVSS) also allows the decryption of secret image by stacking of physical transparencies but clarity and contrast of the decoded secret image will be increased progressively with the number of stacked shares. Most of the existing researches on PVSS suffer with the common problems like space-inefficiency(pixel expansion) and noise-like shares. This paper proposes a novel PVSS scheme with four or more number of space-efficient as well as meaningful shares. To achieve this, an efficient preprocessing approach and a basis matrix creation algorithm have also been proposed. This paper also addresses many avoidable encryption limitations like explicit requirement of codebook, restriction on number of shares etc. Experiments show that the contrast of reconstructed secret image is 50% and can be easily decrypted by only human visual system without any cryptographic computation.

Survey Paper on Digital Image Sharing by Diverse Image Media

Conventional cryptography is a method of transforming message into an unreadable format called as cipher text. This cipher text can easily be shared over the network without fear but anyone can get message easily by applying key on cipher text. Sharing and delivering secret images over the network is also known as a visual secret sharing (VSS) scheme. However main drawback of VSS scheme is that it is experience from high transmission risk due to the shares are like noise. As the shares are like noise which in turn lead to cause the attackers attention. To solve this problem mechanism is developed called Natural image based visual secret sharing (NVSS). This paper is motivated by need of novel mechanism to transfer the secret images over network. In proposed work for regeneration of secret image a generated noisy share, natural images and seed (needed for random functions used) are required at the receiving end. Though generated share is noisy and its contents are not recognizable, overall structure may be visible in some cases. So data hiding is should be performed on generated share to hide that structure (texture) in noisy share.

A Survey on Sharing Secret Image using NVSS Scheme

sharing is of great importance for sharing secret or confidential information. This information can be in the form of documents, images, photographs and many more. Most of the previous visual secret sharing scheme uses shares to conceal secret images. The shares may be printed or in digital form. When the secret image is hidden into the shares, noise- like pixel appears which increase the risk of transmission. Attackers look at image having noise-like pixels with suspicion and try to intercept the image. Thus image having noise is not safe for transmission over network. Due to this transmission risk is involved in visual secret sharing. In order to overcome such problems some authors have presented another scheme known as Natural image based Visual Secret Sharing Scheme (NVSS Scheme). In this scheme the transmission of secret image occurs through different media in order to protect the secret. The n out of n NVSS scheme can transmit a digital secret image by randomly choosing n-1 natural images and one noise share. Natural images may be in digital or printed form. Noise-like share is produced by natural image and printed image. The natural shares which are unaltered minimize the risk associated during transmission. Keywordsatural images, transmission risk, visual secret sharing,

An Optimal (k,n)Visual Secret Sharing Scheme for Information Security

Recently, based on the concept of Visual Secret Sharing (VSS) scheme proposed by Naor and Shamir in 1994, many of schemes have been proposed to protect the security of binary image. Yet, the problems of pixel expansion, extensive codebook designs, and lossy recovery are still unsolved. The current paper attempts to propose a new (k,n) scheme to refute the pixel expansion based on codebook and transpose of matrices. This scheme will offer promising solutions for the security condition, computation complexity, storage requirement, fast network transmission, and reconstructing the secret image accurately without any distortion.

A Novel XOR-based Visual Secret Sharing Scheme with Random Grid

The basic concept of secret image sharing is to encrypt a secret image into a number of meaningless share images. Except for all the images, no information should leak out from any of the share images. The original secret image is printed onto transparencies, and stacking these transparencies directly reveals the original image. The advantage lies in the fact that no computational cost is encountered, and only the human visual system is required to decode the secret image. The visual secret sharing scheme is to encrypt a secret image into a set of share images to increase the encryption capacity. However, the schemes available use a codebook, and used pixel expansion to encrypt secret images into share images. In general, pixel expansion of twice the original order is seen. It is neither practical nor the best solution when secret images are more in number. This paper proposes a novel visual secret sharing scheme that can share a binary secret image on two share images with no codebook requirement. The experimental result reveals that the proposed approach has high contrast and also has an excellent recovery quality of the secret image. The recovered secret image type is lossless.

An enhanced threshold visual secret sharing based on random grids

Random grids (RG)-based visual secret sharing (VSS) scheme can easily avoid the pixel expansion problem as well as requires no codebook design. However, previous scheme still suffers from low visual quality. In this paper, a new threshold RG-based VSS scheme aiming at improving the visual quality of the previewed image is presented. Compared with previous schemes, our scheme can gain better visual quality in the reconstructed images as well as (k, n) threshold. In addition, the factor affecting the visual quality is analyzed and the differences between related approaches are discussed.

Friendly progressive random-grid-based visual secret sharing with adaptive contrast

Visual secret sharing (VSS) schemes providing secret communication services are classified into two categories depending on the method of encoding the secret: visual cryptography (VC)-based and random grid (RG)-based schemes. A friendly progressive version of the VC-based VSS scheme was presented in 2008; however, it is marred by pixel expansion, which is the innate deficiency of conventional VC-based VSS schemes. This paper proposes a suitable user-friendly RG-based VSS scheme with progressive secret reconstruction and without pixel expansion. The experimental results of the developed scheme validated its feasibility, and a theoretical analysis demonstrated its visual quality and security.

Visual multiple-secret sharing for flexible general access structure by random grids

For visual secret sharing (VSS), general access structure (GAS), which can freely define the qualified set and the forbidden set, provides dealers the ability to share secret information with the qualified set but not the forbidden set. In previous studies, the proposed GAS schemes have focused on strong GAS, but it has retained restrictions and inconvenience in some secret-sharing scenarios. Recently, the random-grid-based VSS (RG-based VSS) technique has aimed to overcome the problem of pixel expansion from which the visual-cryptography-based VSS (VC-based VSS) techniques usually suffer. This paper presents a flexible GAS VSS scheme by RG that is appropriate for wide use and that serves special cases like (2, n), (n, n), and (k, n). The paper also outlines how the scheme can be extended for multiple secrets. The performance and the security of the scheme are theoretically analyzed.

A New Simple Non-Expansion Algorithm for (2,2) - Visual Secret Sharing Scheme

Visual cryptography (VC) is a powerful encryption technique which combines perfect secrecy and secret sharing in cryptography with respect to images. VC takes a binary image (the secret) and divides it into two or more pieces known as shares (transparencies). When the shares are superimposed, the secret can be recovered. One of the distinguishing features of VC is that it needs no computational power for decryption. All what VC needs for decryption is the human visual system (the human eye). Two main factors affect the quality of a visual cryptography scheme; the pixel expansion and the contrast. In this papers we propose a new simple non-expansion algorithm for (2,2)-visual secret sharing scheme (VSS). The shares produced by this algorithm and the reconstructed image are not expanded in size, and all have the same size as the original (secret) image. It encodes the original (secret) image a 4-pixel blockwise to 4-pixel blocks in each share.

Fake Shares Detection on a Visual Secret Sharing Scheme by Rational Interpolation

In the visual secret sharing scheme based on polynomial interpolation, e.g. Lin and Tsai's scheme, fake share images may give incorrect secret information. We propose a method to identify or detect them using a technique by rational interpolation.

Enhanced Contrast of Reconstructed Image for Image Secret Sharing Scheme Using Mathematical Morphology

Visual secret sharing (VSS) is one of the cryptographic techniques of Image secret sharing scheme (ISSS) that performs encoding of secret message image (text or picture) into noise like black and white images, which are called as shares. Shares are stacked together and secret message image is decoded using human visual system. One of the major drawbacks of this scheme is its poor contrast of the recovered image, which improves if computational device is available while decoding. In this paper, we propose to improve poor contrast of classical VSS schemes for text or alphanumeric secret messages and low entropy images. Initially, stacked image is binarized using dynamic threshold value. A mathematical morphological operation is applied on the stacked image to enhance contrast of the reconstructed image. Moreover, a method is proposed that allows the size of the structuring element to change according to the contrast and the size of a stacked image. We perform experiments for different types of VSS schemes, different share patterns, different share types (rectangle and circle), and low entropy images. Experimental results demonstrate the efficacy of the proposed scheme.

Robust Cheat-prevention for Random Grids Based Visual Secret Sharing Scheme

In conventional visual secret sharing (VSS), a secret image is encrypted into noise-like random-looking shares, a subset of which when stacked together reveal the secret. Random grids (RG) eliminate pixel expansion and extensive codebook designs of conventional VSS. However, like conventional VSS, RG-based VSS are prone to collusion attacks. Existing cheat-prevention algorithms reduce the probability of collusion attacks, but these do not consider issues arising due to noise-like nature of the shares. We introduce two issues that may lead to false accusations and we devise a robust cheat-prevention algorithm to tackle these. Experimental results validate the efficacy of the algorithm.

Visual multi secret sharing by cylindrical random grid

Visual secret sharing (VSS) is the process of encoding a secret image into several share images in which the original secret image can be reconstructed and recognized by stacking all of the share images together. VSS has two categories: visual cryptography (VC) and Random Grid (RG). The VC is affected by various drawbacks such as: enlarging the size of original image, need for a codebook and the limitation to encode only one secret image at a time. RG solves the first two drawbacks of VC. To solve the third drawback and provide a solution to optimize recent algorithms, we propose a novel RG-based VSS scheme which encodes several secret images at a time. Instead of using only (2, 2) visual secret sharing, (2, n) and (n, n) is employed. This scheme has the ability to encode one or multiple secret images into multiple shares in place of two shares. In our proposed scheme, instead of Circular Random Grid, a new algorithm named Cylindrical Random Grid is used. It encrypts multiple secret images into two or more shares. To decrypt the first secret image, shares are stacked together. For decrypting of other secret images, one of the stacked shares is rotated in a fixed size over other shares based on the number of secret images which are encrypted. This algorithm is simple to implement and less time consuming.

Digital Image Sharing by Diverse Image Media

Conventional visual secret sharing (VSS) schemes hide secret images in shares that are either printed on transparencies or are encoded and stored in a digital form. The shares can appear as noise-like pixels or as meaningful images; but it will arouse suspicion and increase interception risk during transmission of the shares. Hence, VSS schemes suffer from a transmission risk problem for the secret itself and for the participants who are involved in the VSS scheme. To address this problem, we proposed a natural-image-based VSS scheme (NVSS scheme) that shares secret images via various carrier media to protect the secret and the participants during the transmission phase. The proposed (n,n)- NVSS scheme can share one digital secret image over n-1 arbitrary selected natural images (called natural shares) and one noise-like share. The natural shares can be photos or hand-painted pictures in digital form or in printed form. The noise-like share is generated based on these natural shares and the secret image. The unaltered natural shares are diverse and innocuous, thus greatly reducing the transmission risk problem. We also propose possible ways to hide the noise-like share to reduce the transmission risk problem for the share. Experimental results indicate that the proposed approach is an excellent solution for solving the transmission risk problem for the VSS schemes.

Secret Image Sharing for General Access Structures using Random Grids

This paper presents a visual secret sharing (VSS) scheme for general access structures by using random grids. Compared to the existing VSS schemes for general access structures, the proposed scheme generates the shares of same size as that of the original secret image and does not require any codebook prior to encryption process. With these advantages, the proposed scheme broadens the potential applicability of random-grid based VSS. We prove that the proposed scheme gives the strong access structure. Formal proofs, security analysis and experimental results are given to demonstrate both the feasibility and the correctness of the proposed scheme.

A random grid-based cyclic access structure VSS scheme for multiple secret images

Visual secret sharing (VSS) schemes based on visual cryptography (VC) or random grids (RGs) have been proposed in the past decade with the advantages of easy implementation, efficiency secret recovering and perfect security. As the concept of multiple secret images has gained more and more attention in academia, the novel concept of VC-based VSS with cyclic access structure has been discussed recently, which is a special case of multiple VSS, allowing participants to reconstruct the secret with the one next or last to him/her in a cyclic order. To obtain the benefit of RG-based VSS compared with VC-based VSS, this paper proposes the new VSS scheme with cyclic access structure for multiple secret images by random grids. The experimental results and theoretical security analysis demonstrate the feasibility.