Blockchain, as a rapidly developing technology in nowadays, involves multi-party collaboration scenarios. However, as the number of users grows, security issues in blockchain systems also increase, driving the need for features such as collusion resistance and traceability. To meet the needs of multi-party collaboration on the blockchain, we propose a blockchain-based collusion-resistant and traceable broadcast encryption scheme. On the one hand, the traitor tracing scheme is adopted to effectively enable accountability for malicious users. On the other hand, the SM2 public key encryption algorithm is deployed to satisfy high security requirement with relatively low computational costs. Security analysis demonstrates that the proposed scheme has the same level of security as the SM2 algorithm. Performance evaluation shows that the proposed scheme is superior to the relevant schemes and maintains functionalities such as collusion-resistant and traitor tracing.

With the rapid development of smart grid technologies, ensuring secure and efficient collaboration among distributed grid units has become a significant challenge. However, existing works suffer from the key escrow problem and single points of failure. Moreover, decentralized alternatives often lack efficient mechanisms to prevent rogue nodes from manipulating collaborative decisions. This paper proposes a certificateless multi-signature scheme named MagicCMS, which is based on a magic square structure. By integrating element-based node collaboration through magic squares, MagicCMS ensures signature generation only when authorized node groups meet predefined constraints. This enhances security against rogue nodes. Additionally, the system utilizes a decentralized key management solution leveraging blockchain technology, thereby eliminating single points of failure. A rigorous security analysis demonstrates that MagicCMS resists both Type-I and Type-II adversaries and provides protection against rogue-key attacks. Performance evaluations show significant improvements in signature verification efficiency compared to existing schemes. In large-scale scenarios, verification computational costs are reduced by up to 73%.

Bitcoin mixing operations are essential for enhancing transaction privacy by obfuscating the link between transaction inputs and outputs. However, the transparency of blockchain transactions presents significant privacy risks, as transaction details are publicly recorded. To address these challenges, Bitcoin mixing operations are crucial for obfuscating the link between transaction inputs and outputs, thereby enhancing transaction privacy. Whereas, current mixing approaches are limited by several issues, including reliance on trusted third-party services, vulnerability to forgery by malicious participants, and suboptimal efficiency. In response to these challenges, we propose a decentralized Bitcoin mixing scheme named CoinMixMultiSig (CMMS). This scheme designs a two-round collaborative public address generation process, allowing participants to jointly create a public address and send their Bitcoin efficiently to this address before signing. This approach mitigates fraud risks, such as participants dropping out during the mixing process or maliciously altering transaction data, which could lead to asset loss. To enhance security and efficiency, CMMS incorporates a multi-signature mechanism that reduces the overall signature size. The multi-signature mechanism reduces computational and communication overhead, enhancing efficiency and practicality for real-world use. A rigorous security analysis demonstrates that CMMS ensures unforgeability and effectively resists rogue key attacks, providing a reliable and secure option for Bitcoin transactions.

As Flying Ad-hoc Network (FANET) evolves toward larger scales and higher levels of autonomy, the importance of secure and efficient group communication continues to grow. However, resource-constrained unmanned aerial vehicles (UAVs) face dual challenges: limited computational power struggles to meet the high demands of complex cryptographic algorithms, while bandwidth constraints exacerbate communication overhead caused by multi-round interaction mechanisms. Moreover, existing solutions find it hard to support dynamic group environments and are prone to single point of failure (SPoF) in centralized architectures, which significantly compromises system reliability and scalability. To address these issues, this paper proposes a novel key agreement protocol for FANET. The protocol employs an improved tree-based key encapsulation mechanism (iTreeKEM) to support rapid key updates in highly dynamic environments. It reduces the computational cost for each group member by 90.08% even when the group size reaches 128. To further enhance system robustness, the protocol introduces a smart contract-based distributed leader election mechanism, effectively eliminating SPoF. The security of the proposed protocol is guaranteed by the CDH problem under the generalized selective decryption (GSD) model. Finally, we implement the protocol in NS-3 simulations, and the results demonstrate its effective applicability to FANET.

With the rise of blockchain and next-generation networks (NGNs) technologies, privacy and security issues have become the main bottlenecks of the conventional network architecture solution. The asymmetric group key agreement (AGKA) protocol is a practical and effective cryptographic primitive in achieving decentralized authentication for zero-trust architecture. However, conventional AGKA protocols suffer from collusion attack issues and cannot provide privacy-preserving authentication with traceability. This paper aims to develop novel approaches for privacy-preserving authentication and secure data sharing for zero-trust architecture. First, we construct an AGKA protocol, which is so far the first AGKA protocol immune to the collusion attack. Next, we develop an anonymous authentication (AA) scheme that supports the anonymity and traceability properties simultaneously. Moreover, benefiting from the immutability of blockchain, the identity of malicious users can be detected. Third, we design a conditional data sharing (CDS) scheme by means of the secret sharing scheme, which could guarantee the confidentiality and reliability of the users' data from multi-cloud. Finally, we conduct security and performance evaluations, which show that the developed schemes can resist different kinds of attacks with high performance.

Recently, Industrial Internet of Things (IoT) has experienced significant growth and has garnered widespread interest. With industrial IoT, remote users can link and manage various sensing devices and gather instantaneous data from devices, thereby improving efficiency and productivity in industrial settings. However, challenges with existing authentication protocols in the Industrial IoT environment have been identified. To address these shortcomings, we propose a high-availability authentication and key agreement protocol for IoT-based devices, which reduces computational and communication overheads. In addition, our protocol offers privacy protection to users as the data message is transmitted by the users' pseudonym, helping to conceal their real identity. Furthermore, we also consider device dynamic updates in our proposed protocol. Security proof and analysis are provided to prove that our proposed protocol can withstand known attacks. In addition, performance analysis shows that our proposed protocol is a more efficient option than other related protocols.

In the cloud computing context, group data sharing, which is highly convenient for people who intend to share data with multiple members of a group, has attracted extensive research attention. However, the question of how data security might be ensured in this scenario, particularly as regards the security of group session keys, still remains an open one. To support secure group data sharing in cloud computing, it is essential to design a key agreement protocol characterized by both high flexibility and efficiency. Accordingly, this paper proposes a key agreement protocol based on Latin Square to reinforce the security of group data sharing. This protocol supports an arbitrary number of members to participate in a group and make equal contributions to generating a common session key among themselves. Compared with previous works, both the communication and the computational complexity in this protocol are significantly reduced. In addition, the services of authentication, key confirmation and fault tolerance are provided, enabling the protocol to resist different types of attacks. The results of both theoretical and experimental analysis indicate that the proposed protocol can efficiently support secure cloud data sharing for large-scale groups.

For the node classification problem, the traditional graph convolutional network (GCN) and many of its variants achieve the best results at shallow layers, especially for sparse graphs, which do not take full advantage of the higher-order neighbor information of the nodes in the graph. However, multiple stacked graph convolutional networks will suffer from the over-smoothing problem, resulting in ineffective differentiation between different classes of nodes in the graph. To address this problem, we propose an adaptive graph convolutional network based on decouple and residuals (ADR-GCN) to alleviate the over-smoothing problem. The model first obtains the initial representation of nodes using autoencoder and then decouples the representation transformation of nodes and feature propagation. In addition, we add initial residuals to the feature propagation of nodes and adaptively selects the appropriate local and global information of each node to obtain node representations containing rich information. Finally, we use a softmax classifier to generate the final node prediction. The experimental results on seven datasets show that the classification accuracy of ADR-GCN improves 1.3%-4.1% compared with GCN, which shows that the model can better alleviate over-smoothing,

The vehicular ad hoc network (VANET) has become a hot topic in recent years. With the development of VANETs, how to achieve secure and efficient machine learning in VANETs is an urgent problem to be solved. Besides, how to ensure that users obtain the accurate results of machine learning is also a challenge. Based on the homomorphic encryption and secure multiparty computing technology, a flexible and privacy-preserving collaborative filtering scheme is proposed to accomplish the personalized recommendation for users, which is based on users’ interests and locations. On the one hand, the data can be updated by users flexibly to ensure the freshness and accuracy of the dataset of interest. On the other hand, the weighted values of user interest can be safely sorted to improve the accuracy of collaborative filtering effectively. Moreover, a novel collaborative filtering algorithm based on the homomorphic encryption technology is designed, which can guarantee that the calculated decryption result by machine learning is the same as the plaintext. Note that the privacy of user data can be preserved during machine learning in this algorithm. Both theoretical and experimental analyses demonstrate that the proposed scheme is secure and efficient for collaborative filtering in cloud computing in VANETs.

With the development of the Internet of Things and the demand for telemedicine, the smart healthcare system has attracted much attention in recent years. As a platform for medical data interaction, the smart healthcare system is demanded to ensure the privacy of both the receiver and the sender, as well as the security of data transmission. In this paper, we propose a privacy-preserving data transmission scheme where both secure ciphertext conversion and malicious users identification are supported. In particular, the OT m n protocol is introduced to guarantee the two-way privacy of communication parties. Meanwhile, we adopt proxy reencryption algorithm to support secure ciphertext conversion so as to ensure the confidentiality of data in many-to-many communication pattern. In addition, by taking advantage of the concept of blockchain technology, a novel OT m n protocol is proposed to prevent data from being tampered with and effectively identify malicious users. Theoretical and experimental analyses indicate that the proposed scheme is practical for smart healthcare with high security and efficiency.

Intelligent transportation systems (ITS) have always been an important application of Internet of Things (IoT). Today, big data and cloud computing have further promoted the construction and development of ITS. At the same time, the development of blockchain has also brought new features and convenience to ITS. However, due to the endless emergence of increasingly advanced types of attacks, the security of blockchain-based ITS needs more attention from industry and academia. In this paper, we focus on exploring the primitives in cryptography to guarantee the security of blockchain-based ITS. In particular, the authentication, encryption, and key management schemes in cryptography are discussed. Furthermore, we propose two methods for achieving the threshold key management in blockchain-based ITS. The proposed threshold key management scheme (with threshold t ) enables various stakeholders to recover a secret if the number of participated stakeholders is at least t . It should be noted that the proposed threshold key management scheme is efficient and secure for multiple users in blockchain-based ITS, especially for the data-sharing scenario.

With the development of wireless communication and the pervasive Internet of Things, vehicular ad hoc networks (VANETs) have attracted much attention in recent years. As a platform for vehicular communication and management, VANETs require the guarantee of security and efficiency for the resources constrained and unreliable networks. In this article, a data-sharing scheme is proposed for VANETs where both efficient key updating and dynamic property of VANETs are supported. In particular, the symmetric balanced incomplete block design (SBIBD) in combinatorics is introduced to ensure secure and efficient VANETs while the concept of indistinguishability obfuscation is employed to support efficient key updating. In order to simultaneously satisfy the resources constrained and real-time requirements of VANETs, both serial and parallel construction of the SBIBD is implemented by the shift register. Taking advantage of this efficient sequential logical circuit, we eliminate the complicated construction of the SBIBD, thereby, making it effective for the resource-constrained environment. Theoretical and experimental analyses indicate that the proposed scheme is practical for VANETs with high security and efficiency.

The renewable energy plays an increasingly important role in many fields such as lighting, automobile, and electric power. In order to make full use of the renewable energy, various smart Internet of Thing (IoT) devices are deployed. However, in the field of energy management, the two-way mismatch between the demand and the supply of the renewable energy will greatly affect the efficiency of the renewable energy. In addition, the security threat of the energy data and the privacy leakage of the user may hinder the further development of smart IoT devices. Therefore, how to achieve consistency and balance between the demand and the renewable energy supply and how to guarantee the security and privacy of smart IoT devices become the key problems of the energy-efficient smart environment. In this paper, a secure and intelligent energy data management scheme for smart IoT devices is proposed. It is worth noting that, with the help of artificial intelligence (AI) technologies and secure cryptography primitives, the proposed scheme realizes high-efficient and secure energy utilization in a smart environment. Specifically, the proposed scheme aims at improving the efficiency of the energy utilization in the multidimensions of a smart environment. In order to realize the fine-grain energy management of smart IoT devices, strategies of three different dimensions are considered and realized in the proposed scheme. Moreover, technologies in AI are applied and integrated into the energy management scheme. The analysis shows that the proposed scheme can make full use of the renewable energy in smart IoT devices.

Data sharing in cloud computing enables multiple participants to freely share the group data, which improves the efficiency of work in cooperative environments and has widespread potential applications. However, how to ensure the security of data sharing within a group and how to efficiently share the outsourced data in a group manner are formidable challenges. Note that key agreement protocols have played a very important role in secure and efficient group data sharing in cloud computing. In this paper, by taking advantage of the symmetric balanced incomplete block design (SBIBD), we present a novel block design-based key agreement protocol that supports multiple participants, which can flexibly extend the number of participants in a cloud environment according to the structure of the block design. Based on the proposed group data sharing model, we present general formulas for generating the common conference key IC for multiple participants. Note that by benefiting from the (v, k + 1, 1)-block design, the computational complexity of the proposed protocol linearly increases with the number of participants and the communication complexity is greatly reduced. In addition, the fault tolerance property of our protocol enables the group data sharing in cloud computing to withstand different key attacks, which is similar to Yi's protocol.

The concept of the Social Internet of Things (SIoT) can be viewed as the integration of prevailing social networking and the Internet of Things, which is making inroads into the daily operation of many industries. Smart grids, which are cost-effective and environmentally friendly applications, are a promising field of the SIoT. However, security and privacy concerns are the dark aspects of smart grids. The goal of this paper is to address the security and privacy issues in the vehicle-togrid (V2G) networks with the intention of promoting a more extensive deployment of V2G networks for smart grids. Driven by this motivation, in this paper, we propose a robust key agreement protocol that can achieve mutual authentication without exposing the real identities of users. Efficiency is also a major concern in resource-constrained environments. By leveraging only hash functions and bitwise exclusive-OR operations, the proposed protocol is highly efficient compared with pairing-based protocols. In addition, we define a formal security model for our privacy-preserving key agreement protocol for V2G networks. Using this model, a formal security analysis shows that the proposed protocol is secure. Moreover, an informal security analysis demonstrates that our protocol can withstand different types of attacks.

Nowadays, Software Defined Network (SDN) develops rapidly for its novel structure which separates the control plane and the data plane of network devices. Many researchers devoted themselves to the study of such a special network. However, some limitations restrict the development of SDN. On the one hand, the single controller in the conventional model bears all threats, and the corruption of it will result in network paralysis. On the other hand, the data will be increasing more in SDN switches in the data plane, while the storage space of these switches is limited. In order to solve the mentioned issues, we propose two corresponding protocols in this paper. Specifically, one is an anonymous protocol in the control plane, and the other is a verifiable outsourcing protocol in the data plane. The evaluation indicates that our protocol is correct, secure, and efficient.

Cyberspace has become the most popular carrier of information exchange in every corner of our life, which is beneficial for our life in almost all aspects. With the continuous development of science and technology, especially the quantum computer, cyberspace security has become the most critical problem for the Internet in near future. In this paper, we focus on analyzing characteristics of the quantum cryptography and exploring of the advantages of it in the future Internet. It is worth noting that we analyze the quantum key distribution (QKD) protocol in the noise-free channel. Moreover, in order to simulate real situations in the future Internet, we also search the QKD protocol in the noisy channel. The results reflect the unconditional security of quantum cryptography theoretically, which is suitable for the Internet as ever-increasing challenges are inevitable in the future.

Group data sharing in cloud environments has become a hot topic in recent decades. With the popularity of cloud computing, how to achieve secure and efficient data sharing in cloud environments is an urgent problem to be solved. In addition, how to achieve both anonymity and traceability is also a challenge in the cloud for data sharing. This paper focuses on enabling data sharing and storage for the same group in the cloud with high security and efficiency in an anonymous manner. By leveraging the key agreement and the group signature, a novel traceable group data sharing scheme is proposed to support anonymous multiple users in public clouds. On the one hand, group members can communicate anonymously with respect to the group signature, and the real identities of members can be traced if necessary. On the other hand, a common conference key is derived based on the key agreement to enable group members to share and store their data securely. Note that a symmetric balanced incomplete block design is utilized for key generation, which substantially reduces the burden on members to derive a common conference key. Both theoretical and experimental analyses demonstrate that the proposed scheme is secure and efficient for group data sharing in cloud computing.

Machine-to-machine (M2M) communication, an automated communications technology for the equipment or devices, holds great promise in every corner of the modern society, such as civil transportation, smart homes, smart grids, and industrial automation. The M2M technology is still in its infancy, and further development and deployment of M2M systems hinges on establishing an efficient and secure information management system with a satisfactory security level. In this paper, we extend the idea of (t, n) secret sharing for information transmission in M2M with high security and efficiency. Specifically, a secret is divided into 2k shares, and then, transmitted through 2k node-disjoint paths constructed by the Latin square. Note that in our scheme, the secret key is simultaneously transmitted along with the encrypted message through these 2k paths from the source node to the destination node, which greatly improves the efficiency of point-to-point communications in M2M systems. Furthermore, owing to the properties of (t, n) secret sharing, the security of M2M communications is guaranteed. In addition, to avoid dishonest participants, verifiable secret sharing is supported in the proposed scheme. Sufficient theoretical proof and performance analysis demonstrate that our scheme is secure and efficient for M2M communications.