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We propose a verifiable $(t,n)$-threshold secret sharing scheme using Lagrange interpolation and secure cryptographic hash functions. This scheme is an improvement of Shao’s scheme [Inform. Sci.278 (2014) 104–109]. In our variant, verification of shares is achieved through computation of their multiplicative inverses in conjunction with a secure hash function such as SHA-3. This idea results in a significant size reduction, in comparison with Shao’s scheme, to the shares assigned to each participant. Applications of the proposed scheme include sharing of cryptographic keys, access codes, etc. Furthermore, we improve our construction to present a method for secret sharing with adjustable access structure. This can further be extended to a secret sharing scheme with essential participants, where any authorized set of participants must meet a threshold in the number of essential participants it contains. While our proposal has smaller share sizes compared to Shao’s scheme, it also adds the capabilities of changeable parameters and essential participants.

A secret sharing scheme is a system designed to share a piece of information or the secret among a group of people such that only authorized people can reconstruct the secret from their shares. Since Blakley and Shamir proposed threshold secret sharing schemes in 1979 independently, many secret sharing schemes have been constructed. In this paper, we present several threshold schemes that are generalizations of Shamir's secret sharing scheme.

In principle, every linear code can be used to construct a secret sharing scheme. However, determining the access structure of the scheme is a very difficult problem. In this paper, we study MacDonald codes over the finite non-chain ring ${\mathbb{F}}_p+v{\mathbb{F}}_p$, where p is a prime and $v^2=v$. We provide a method to construct a class of two-weight linear codes over the ring. Then, we determine the access structure of secret sharing schemes based on these codes.

In this paper, we propose a neural-network approach for visual authorization, which is an application of visual cryptography (VC). The scheme contains a key-share and a set of user-shares. The administrator owns the key-share, and each user owns a user-share issued by the administrator from the user-share set. The shares in the user-share set are visually indistinguishable, i.e. they have the same pictorial meaning. However, the stacking of the key-share with different user-shares will reveal significantly different images. Therefore, the administrator (in fact, only the administrator) can visually recognize the authority assigned to a particular user by viewing the information appearing in the superposed image of key-share and user-share.

This approach is completely different from traditional VC approaches. The salient features include: (i) the access schemes are described using a set of graytone images, and (ii) the codebooks to fulfil them are not required; and (iii) the size of share images is the same as the size of target image.

In this paper, a new cryptographic protocol to securely share a secret among a set of participants is presented. It is based on the use of non-reversible elementary cellular automata with rule numbers 90 and 150. The protocol is shown to be perfect and ideal.

An algorithm to share a secret among a set of users is introduced in this work. It is based on the use of linear cellular automata over the finite set 𝔽₂ and it is considered as a generalization of a previous work due to the authors dealing with an elementary cellular automata-based secret sharing scheme. The algorithm is shown to be secure, ideal, and perfect.

Most semi-quantum secret sharing protocols are suitable for the application with three participants. Based on the n-level states, a multiparty semi-quantum secret sharing protocol is proposed. Compared with similar protocols, it has the merits as follows. (1) The dealer only needs to prepare the single photon sequence without using any product state or entangle state. (2) To share a secret, the classical parties need not have the ability of measurement. They only need to reorder the photon sequence and send it to the receiver. (3) The dealer knows nothing about any agent’s secret shadow. Therefore, it is infeasible for the dealer to impersonate the classical participant to pool the secret shadow during the secret recovering phase. (4) Theoretically, the qubit efficiency of the proposed protocol is asymptotically 100%. The protocol is secure against famous attacks such as intercept-resend attack, measurement-resend attack and entangle-measure attack.

In this paper, we propose an efficient secret sharing scheme without pixel expansion. The scheme first uses the VQ-compression method to compress a secret image. This allows senders to share a larger secret image than other methods. Moreover, the proposed method also allows participants to reconstruct a lossless secret image. The generated shadows are meaningful with high quality, so the image does not attract any suspicion from attackers. Because the scheme uses XOR operation during the construction and revealing phases, it is suitable for secret sharing applications.

Internet of Things (IoT) is a modern technology that is applicable almost everywhere nowadays. Everything is connected to the Internet in the modern digital era. IoT is a collection of things that are interconnected to share information. Devices connected to IoT networks have some limitations in performing heavy computational tasks because of the availability of less computational and battery power. Attribute Based Encryption (ABE) is a modern public-key cryptographic technique that provides privacy with access control. The bilinear map is an expensive operation that is used in most of the ABE schemes. Elliptic Curve Cryptography (ECC) is an alternative for bilinear pairing to reduce the computation of encryption and decryption in ABE schemes.

The process of encryption and decryption of ABE is a heavy computational task for resource-constrained devices. In this paper, an outsourcing-based decryption of ABE using ECC is proposed to reduce the decryption overhead of devices that have limited computational resources. Our scheme divides the computation of the decryption of ABE into two stages: first, the partial decryption of ciphertext in the cloud server, and second, the final decryption of partially decrypted ciphertext by the data user to retrieve the original message. This scheme is secure against the malicious cloud server by adding a blinding factor into the secret to be shared. The blinding factor is shared with intended users through attribute authority. The experimental results demonstrate that our scheme can reduce the decryption complexity and save the computational time of devices, compared to the existing schemes. Thus the proposed scheme is applicable for lightweight devices used in IoT.

We develop the concept of quantum carrier and show that messages can be uploaded and downloaded from this carrier and while in transit, these messages are hidden from external agents. We explain in detail the working of the quantum carrier for different communication tasks, including quantum key distribution, classical secret and quantum state sharing among a set of n players according to general threshold schemes. The security of the protocol is discussed and it is shown that only the legitimate subsets can retrieve the secret messages, the collaboration of all the parties is needed for the continuous running of the protocol and maintaining the carrier.

Cryptographic key is the central problem in cryptographic techniques. The key based on password protection is not enough secure because of the low entropy in user chosen passwords that can be exploited to launch password-guessing attacks. And the length of cryptographic key generated from user's biometric features directly is limited. Differ from prior methods, a novel scheme of cryptographic key generation based on biometric features and secret sharing is proposed. Biometric feature vectors is transformed through orthogonal matrix, and mapped to integer spaces. Then, a steady integer vector is obtained, and can be utilized to bind with cryptographic key by Shamir's secret sharing scheme. This method may realize the security of key storing, and can produce the key of the arbitrary length.

This paper firstly provides a formal definition of the n out of n extended color visual cryptography scheme (ECVCS) based on the XOR cipher, where a color secret image and k color cover images are encoded into n shares in such a way that the n shares present cover images individually and any n shares and above will recover the secret image while any less than n shares, will not reveal any information about the secret image. The proposed scheme in the paper has no extra expansion and it can easily trade the visual quality of the recovery image with the visual quality of shares by changing the value of a certain parameter in the scheme. The validity of the proposed scheme is verified by formal proofs, and its feasibility is demonstrated by computer simulations.

This paper serves as an introduction to secret sharing scheme, and it provides the fundamental understandings to the scheme from various aspects. We first review the basics of a Shamir threshold scheme, and discuss various enhancements so that the scheme can be proactive and verifiable. We then show how a Shamir scheme can be extended to realize any general access structure. We also point out the relationship between a Shamir scheme and other topics such as error correction code, ramp scheme, information disposal algorithm and multiparty computation. Finally, we briefly discuss other platforms for its implementation.

By chaotic encryption system and introducing the trusted third party (TTP), in this paper, an anti-cheating visual cryptography scheme (VCS) is proposed. The scheme solved the problem of dishonest participants and improved the security of chaotic encryption system. Simulation results and analysis show that the recovery image is acceptable, the system can detect the cheating in participants effectively and with high security.

To protect the confidentiality and integrity of network digital images, a security image transmission method based on data segmentation STDDS was proposed in the paper. Firstly, the image was divided into segments and encrypted by groups of non-linear encryptions to generate secrets and check sums; the received secrets were verified by the recipient to detect illegal modification. The corresponding two sides dynamically calculated the encryption variables through pre-deployed hash functions, which avoids leaks due to the simultaneously transmission of cipher text and encryption variables. In addition, even if some cipher text was corrupted during the transmission, the plaintext could also be recovered by the redundancy secrets, which ensures the data availability. STDDS has good scalability, such that the data segmentation and polynomial encryption does not depend on the type and structure of the original data, thus STDDS can be combined with other security schemes based on the demands,. Simulation results demonstrated that, compared with traditional Arnold scrambling, chaotic encryption, the data confidentiality can be achieved by STDDS with a smaller time cost, and the integrity and availability of data can be greatly improved in the case of strong noise and data lost.