Image secret sharing (ISS) is gaining popularity due to the importance of digital images and its wide application to cloud-based distributed storage and multiparty secure computing. Shadow image authentication generally includes shadow image detection and identification, and plays an important role in ISS. However, traditional dealer-participatory methods, which suffer from significant pixel expansion or storing auxiliary information, authenticate the shadow image mainly during the decoding phase, also known as unidirectional authentication. The authentication of the shadow image in the distributing (encoding) phase is also important for the participant. In this study, we introduce a public key based bidirectional shadow image authentication method in ISS without pixel expansion for a ( k,n ) threshold. When the dealer distributes each shadow image to a corresponding participant, the participant can authenticate the received shadow image with his/her private key. In the decoding phase, the dealer can authenticate each received shadow image with a secret key; in addition, the dealer can losslessly decode the secret image with any k or more shadow images. The proposed method is validated using theoretical analyses, illustrations, and comparisons.

Secret image sharing (SIS) has received increased attention from the research community because of its usefulness in multiparty secure computing, access control, blockchain distributive storage and other security-oriented applications. Prevention of fake and dishonest participants is a key issue that has spurred interest in practical applications of SIS. Unfortunately, most previous SIS schemes failed to detect and locate fake or dishonest participants. In this article, an SIS for a ( k,n )-threshold without pixel expansion is presented, which can detect and locate both fake and dishonest participants. Using a screening operation, the proposed approach fuses the benefits of polynomial-based SIS, visual cryptographic scheme (VCS) , and hash functions to authenticate separate participants both with and without a dealer. In addition, the proposed approach achieves lossless rebuilding of the secret image. Analyses and experiments are conducted in this study to establish the effectiveness of the presented approach.

With the widespread use of WeChat Mini Programs, their security has attracted more and more attention. The WeChat Mini Program can be accessed by scanning a WeChat Mini Program code. We should protect the code thus to protect the Mini Program. In this paper, based on studying the function in each pattern of WeChat Mini Program codes, a visual secret sharing (VSS) scheme for WeChat Mini Program codes (MPCVSS) with (n,n)(n≥4) threshold is proposed to control and identify the users of Mini Program. MPCVSS combines the error-correcting characteristic of WeChat Mini Program codes with the theory of VSS. A secret WeChat Mini Program code is shared into n shared codes slightly modified from n cover codes. Each shared code is a valid code that can be scanned and decoded correctly. The secret code can be recovered by XORing n shares. The recovered code can be decoded as the same secret Mini Program. Theoretical analysis and experiments show that the proposed VSS scheme is practical and feasible.

A mini program code (also known as sunflower code) comes with WeChat mini program APPs. With the popularization of mini program APPs, mini program codes have become more and more widely used. As a new carrier, the study of information hiding technology based on mini program code is of great significance for the expansion of covert communication carriers and can also deal with security problems in advance. At present, to the best of our knowledge, there is no steganographic research based on mini program codes. In this paper, we propose a scheme to embed secret information into mini program codes for the first time. After studying the construction of mini program codes, a coordinate system is constructed to represent its module coordinates. Then, a binary stream of the secret message is embedded into the encoding region or the edge patch. Experiments show that the proposed data hiding scheme is effective and feasible. The embedded secret message could be extracted while keeping the readability of the mini program code. Moreover, the secret payloads of the encoding region and the edge patch for the V-36 mini program code are 72 bits and 29 bits, respectively.

In some particular scenes, the shadows need to be given different weights to represent the participants’ status or importance. And during the reconstruction, participants with different weights obtain various quality reconstructed images. However, the existing schemes based on visual secret sharing (VSS) and the Chinese remainder theorem (CRT) have some disadvantages. In this paper, we propose a weighted polynomial-based SIS scheme in the field of GF (257). We use k , k threshold polynomial-based secret image sharing (SIS) to generate k shares and assign them corresponding weights. Then, the remaining n − k shares are randomly filled with invalid value 0 or 255. When the threshold is satisfied, the number and weight of share can affect the reconstructed image’s quality. Our proposed scheme has the property of lossless recovery. And the average light transmission of shares in our scheme is identical. Experiments and theoretical analysis show that the proposed scheme is practical and feasible. Besides, the quality of the reconstructed image is consistent with the theoretical derivation.

In some particular situations, participants need to recover different secrets both within a group (i.e., intragroup) and between two groups (i.e., intergroup). However, most of the existing multilevel secret sharing (MLSS) and multigroup secret sharing (MGSS) schemes mainly focus on how to protect a secret between one or more groups. In this paper, we propose a polynomial-based scheme to share multiple secret images both within a group and between groups. The random elements’ utilization model of integer linear programming is used to find polynomial coefficients that meet certain conditions so that each participant holds only one shadow image and some of them can recover secrets of both intergroup and intragroup. In addition, our scheme based on polynomials has the advantage of low computational complexity. Theoretical analysis and experiments show that the proposed scheme is feasible and effective.