Progressive Visual Secret Sharing Research Articles

Progressive Secret Sharing with Adaptive Priority and Perfect Reconstruction.

A new technique for progressive visual secret sharing (PVSS) with adaptive priority weight is proposed in this paper. This approach employs the bitwise and eXclusive-OR (XOR) based approaches for generating a set of shared images from a single secret image. It effectively overcomes the former scheme limitation on dealing with an odd number of stacked or collected shared images in the recovery process. The presented technique works well when the number of stacked shared images is odd or even. As documented in experimental results, the proposed method offers good results over binary, grayscale, and color images with a perfectly reconstructed secret image. In addition, the performance of the proposed method is also supported with theoretical analysis showing its lossless ability to recover the secret image. However, it can be considered as a strong substitutive candidate for implementing a PVSS system.

Quality improved (k, n) priority based progressive visual secret sharing

Progressive Visual Secret Sharing (PVSS) is a Visual Secret Sharing scheme which shares a secret image among multiple users and during the decryption this secret image can be reconstructed in a progressive manner. Recently, PVSS has been extended for priority users by giving different importance to different shares. Thus, the higher priority user holding higher importance shares obtains better visual quality compared to the lower priority users. However, existing priority based visual secret sharing suffers from the problem of inconsistent contrast and degraded visual quality. Hence, this paper uses two different approaches namely Codebook approach and Random grid approach to construct (k, n) Priority based Progressive Visual Secret Sharing (PPVSS) without pixel expansion to provide consistent contrast and better visual quality of reconstructed image. Experimental results show the effectiveness of proposed scheme compared to the existing scheme.

Contrast enhancement of Progressive Visual Secret Sharing (PVSS) scheme for gray-scale and color images using super-resolution

Traditional Visual Secret Sharing (VSS) scheme encrypts the secret image into multiple shares. It recovers the secret image based on the “all or nothing” methodology (i.e. all shares must be stacked together to recover the secret image else nothing will be revealed). The modern VSS schemes differ from traditional VSS by progressively recovering the secret image by stacking number of shares. These are also referred as Progressive VSS (PVSS). PVSS schemes generate two types of shares namely 1) meaningful (are the shares which have a meaningful image embedded as the cover image on top of the shares) and 2) noise-like (shares have a random noise-like appearance).In the previous work, we have proposed PVSS based Randomized VSS (RVSS) scheme to recover the secret image by hiding random data into the shares. RVSS achieves the maximum contrast of 70–80% and 70–90% for meaningful and noise-like shares respectively. In this paper, we propose a novel PVSS based super-resolution technique to improve the contrast of RVSS scheme. The experimental results showed that the proposed scheme achieves the contrast of 70–80% for meaningful shares and 99% for noise-like shares. Also, proposed scheme recovers the secret image free from blocking artifacts, for noise-like shares.

Contrast-improved visual secret sharing based on random grid for general access structure

Random grid (RG)-based visual secret sharing (VSS) owns the advantages of no pixel expansion and codebook design. VSS for general access structure (GAS) possesses wider applications than VSS for (k,n) threshold. Previous RG-based VSS studies for GAS had the drawbacks of “all-or-nothing” or low visual quality. In this paper, we will develop a progressive VSS (PVSS) algorithm for GAS with improved visual quality based on RG. We employ different regions of the secret image and their generated corresponding random bits to improve the visual quality of the revealed secret image as well as to gain GAS with progressive feature, where the random bits are divided into three parts. In addition, our scheme has neither pixel expansion nor codebook design due to RG. We show the effectiveness of our proposed scheme in terms of experiments and analyses.

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.

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.

Lossless Recovery of Multiple Decryption Capability and Progressive Visual Secret Sharing

In order to solve the problem of non-restoration of PVSS, in this paper, we propose a method to recover the secret image without using the Boolean operation of the matrix matrix. In the lossless recovery process, each column base matrix will be and exclusive or operation to get the original image anti-color image, and then the image can be obtained by the lossless secret image, this method can be applied to the general ( , ) threshold lossless recovery. In the absence of a computing device, it can be decrypted by superimposing, in the XOR computing device, it can realize lossless recovery. Experimental results show that the proposed algorithm can guarantee the gradual visual secret sharing, complete the restoration of the secret image, the operation is simple and efficient, and has a strong practicability.