Protecting valuable data along the Cyber Security is the one of the strategic issues of cyber defense. The secret sharing scheme is an attractive branch of advanced cryptography that has extremely important role in cyber defense and for the preservation of documents and confidential information against threats such as robbery and unauthorized accesses. In the secret sharing schemes, for increasing security shareholders present a shadow image instead of the genuine share while they are recovering secret images. Thus each shareholder is able to share several images with others by having only one portion of image.In this paper, we define and design a new generating function that by replacing with the Hou Zheng Feng and et.al's generating function, can improved it. Since the new generating function is one-way and hard problem, hence increased the security of improved scheme. Also, with implementation and performing the new scheme again, our revised scheme will be more efficient respect to previous scheme according to the analysis and speed of computations.

Today, a high volume of multimedia information is transmitted in computer networks, such as the internet, that the requirement for achieving high security level against unauthorized access. the visual secret sharing scheme is a cryptographic system without requiring a secret key that is able to encrypt information in a multi - user computer network. in this research, a visual secret sharing scheme including two strategies for binary communications and multiple relationships were considered. in binary communications, an entity plays a role in the role of the server and an entity in the role of the client 's service in this strategy using a network - based visual secret sharing scheme ( 2 , 2 ) a secure approach to establish double relations where the provider entity is sending confidential information after authentication of the client 's service. then, two main phases of registration and verification are performed on the basis of the visual secret sharing scheme based on random networks. in tuple communication ( n , n ) an entity plays a role in the role of the server and several entities in the role of the service, and then two main phases of registration and verification are executed.

In this paper, a novel scheme for lossless meaningful visual secret sharing using XOR properties is presented. In the first step, genetic algorithm with an appropriate proposed objective function created noisy share images. These images do not contain any information about the input secret image and the secret image is fully recovered by stacking them together. Because of attacks on image transmission, a new approach for construction of meaningful shares by the properties of XOR is proposed. In recovery scheme, the input secret image is fully recovered by an efficient XOR operation. The proposed method is evaluated using PSNR, MSE and BCR criteria. The experimental results presents good outcome compared with other methods in both quality of share images and recovered image.

A Publicly Verifiable Secret Sharing (PVSS) scheme, as introduced by Stadler, has a feature where anyone, besides the participants, can verify the validity of the shares distributed by the dealer. Schoenmakers added a new feature, by providing a proof of correctness of the shares released by the players in the reconstruction process. This protocol is claimed to be an improvement on Stadler's and Fujisaki-Okamoto's, both in efficiency and in the type of intractability assumptions. However, Young-Yung improved Schoenmakers' PVSS, using a Discrete-Log instead of a Decision Diffie-Hellman. In this paper, a new PVSS is presented, having an intrinsic difference with its predecessors, that is, the participants can prove the validity of their given shares, implicitly, proving their membership by a zero-knowledge protocol. This feature prevents cheaters from participating in the reconstruction process to gain valid shares. Hence, the new proposed PVSS is more secure than previous ones. Besides, the dealer only sends the amount of commitments limited to the threshold value, regardless of the number of shareholders; this leads to a more dynamic protocol.

‎‎Secret sharing is an important issue in cryptography which has many applications‎. ‎In a secret sharing scheme‎, ‎a secret is shared by a dealer among several participants in such a way that any authorized subset of participants can recover the secret by pooling their shares‎. ‎Recently‎, ‎several schemes based on elliptic curves and bilinear maps have been presented‎. ‎Some of these schemes need a secure channel‎, ‎there are restrictions on the number of secrets‎, ‎or the participants or the dealer are unable to verify the validity of the shares‎. ‎In this paper‎, ‎we present a new verifiable (t‎, ‎n)-threshold multi-secret sharing scheme based on elliptic curves and pairings that does not have any of the above restrictions‎. ‎The hardness of a discrete logarithm problem on elliptic curves guarantees the security of the proposed scheme‎.

in visual secret sharing, the secret image is transformed into several share images and distributed among different people. The share images do not contain any information about the original image, and these images are similar to the noise image. When needed, the original image can be retrieved in the presence of all stakeholders and by stacking the share images. In this regard, the appearance of noisy images may attract the attention of the attackers. To solve this problem, meaningful visual secret sharing was presented. In this article, a method for sharing the image with meaningful shares is introduced. There are a number of hyper parameters in the proposed algorithm. To improve performance, an attempt has been made to determine these hyper parameters using a genetic algorithm. The cost function of the genetic algorithm is the difference between the two values of the correct number of bits of the recovered image and the original image and the correct number of integer bits between the cover image and the shares. The proposed method was evaluated using PSNR, MSE, BCR criteria and presented good results on different images with different number of shares.

Secret Sharing is an important branch of cryptography that is used to protect documents and information from risks such as theft and unauthorized access. In Secret Sharing schemes, shareholders offer a shadow share of the image to enhance security when recovering secret images, rather than the original share. Thus, each shareholder with only one share of the secret image is able to share many images of the secret with others. A new (k,n) threshold secret image sharing scheme base on finite geometry is introduced in paper. In the proposed scheme the secret image is first partitioned into several non-overlapping blocks of k pixels. Every set of k pixel forms a point under a k-dimensional space and the set solution to each generated affine hyperplane, only intersecting at this point stores to the corresponding shared image. The original secret image can be reconstructed by gathering any k or more encrypted shared images. The experimental results show that the proposed image secret sharing scheme is an efficient and secure method.

In this paper, we present two verifiable multi-secret sharing schemes, including a linear multi-secret sharing scheme with public access structure and a threshold (t, n) scheme based on the learning with errors (LWE) problem. The first scheme is a linear multi-secret sharing scheme in which a number of secrets is distributed by a dealer among a set of participants according to the access structure corresponding to each secret. This scheme has the advantages of the earlier ones and it also has many practical applications compared to previous schemes including a multi-use verifiable multi-secret sharing scheme in which the secret reconstruction is according to the dealer’ s preassigned order. In addition, the security of the scheme has been proven in the standard model. This scheme is based on the hard problems in number theory and therefore is not secure against quantum attacks. The second scheme presented in this paper is a lattice-based secret sharing scheme. In this scheme, which is a threshold (t, n) multi-secret sharing scheme, the presence of at least t participants is required for the reconstruction of the secret. The security of this scheme is based on the difficulty of the LWE problem and so it is resistant against quantum attacks.

The Internet of Things has significantly improved healthcare with its promise of transforming technological, social, and economic perspectives. Medical devices with wireless internet access enable remote monitoring of patients, and collectively, these increasingly smart and connected medical devices can provide unique and contemporary medical and health services envisioned to be deployed in a large-scale fashion. For this, medical data and records generally are collected, stored, and shared through open-air wireless networks and public cloud infrastructures, which poses severe challenges regarding the confidentiality of sensitive medical data while maintaining low service overhead and system complexity. This paper presents a novel scheme for secure cloud-assisted Internet of Medical Things connecting patients/smart medical devices to smart applications/medical service providers in a scalable one-to-many fashion to make novel medical services practical. The proposed scheme uses index-based searchable encryption for data screening without decryption. It uses a low-overhead proxy re-encryption scheme for secure data sharing through public clouds