Community detection is of great significance in understanding the structure of the network. Label propagation algorithm (LPA) is a classical and effective method, but it has the problems of randomness and instability. An improved label propagation algorithm named LPA-MNI is proposed in this study by combining the modularity function and node importance with the original LPA. LPA-MNI first identify the initial communities according to the value of modularity. Subsequently, the label propagation is used to cluster the remaining nodes that have not been assigned to initial communities. Meanwhile, node importance is used to improve the node order of label updating and the mechanism of label selecting when multiple labels are contained by the maximum number of nodes. Extensive experiments are performed on twelve real-world networks and eight groups of synthetic networks, and the results show that LPA-MNI has better accuracy, higher modularity, and more reasonable community numbers when compared with other six algorithms. In addition, LPA-MNI is shown to be more robust than the traditional LPA algorithm.

Wireless sensor networks (WSNs) are widely implemented in military, intelligent medical, intelligent transportation, space exploration, and other fields. However, the authentication and communication of WSNs are carried out in the harsh external environment via a public channel, which is more vulnerable to various attacks than the traditional networks. Authentication is the key technology of security measures, but a common authentication scheme is not suitable for WSNs due to limitations of memory, computing, and energy consumption. Therefore, designing a secure and efficient authentication scheme is essential in WSNs. In recent years, several studies proved that the dynamic authentication credential (DAC) is efficient for enhancing the security of the authentication scheme. This article designs a secure authentication scheme for WSNs based on DAC and Intel software guard extensions (SGX). Compared with other DAC authentication schemes, our scheme provides the confirmation action of DAC rotation, which can effectively prevent the asynchronous update problem caused by packet loss. In order to resist the privileged user attack and the authentication table leakage attack, we choose the SGX, which can protect the data in use, as the trusted execution environment in the gateway node, and we adopt SGX to store the master key for protecting the authentication table. Finally, the security of our authentication scheme is verified by BAN logic, the simulation tool AVISPA, and informal security analysis. Through the consumption overhead analysis, the NS3 simulation result, and detailed comparison with other recent schemes, we conclude that our scheme is practical and achieves better security with less overhead.

High-speed railway (HSR) is developing toward automation and intelligence with the motivation of improved safety. The automatic train control system is deeply committed to HSR safety, and depends on long term evolution for railway (LTE-R). The authentication scheme is the primary contributor among all security measures to secure communication in LTE-R. We found vulnerabilities in the authentication mechanism used in LTE-R, such as key leakage, inability to resist privileged user attacks, and large authentication latency. To address these vulnerabilities, we propose a secure and efficient access authentication scheme for LTE-R. Unlike other studies, Our proposal capitalizes on the utilization of blockchain to establish a decentralized authentication system, effectively eliminating the single point of collapse vulnerability. Recognizing the public nature of the blockchain, we integrate the secgear framework to provide robust privacy protection measures. Furthermore, our scheme augments LTE-R access authentication by introducing a handover authentication phase and a password change phase, introducing additional security attributes for enhanced protection. In addition, we have conducted fleshed-out security analysis and simulation experiments, which show that our scheme is able to achieve privacy protection with acceptable efficiency.

In recent years, vehicular ad hoc networks (VANETs) are widely used in transportation and daily life. Because the driving information of a vehicle is transmitted via the public channels of VANETs, the driving information is vulnerable to eavesdropping and tampering. Therefore, ensuring the security of VANETs is particularly important. However, most works assume that the environment of roadside units and on-board units is completely safe, which is an unreasonable stance to take as VANETs are evidently vulnerable to privileged user attack and malware attack. In order to solve this weakness and improve the practicability of VANETs, we adopted Confidential Computing technology and proposed a secure authentication scheme. Our scheme adopted decentralized network architecture and achieved dynamic authentication credentials. In addition, we not only proposed a lightweight vehicle-to-infrastructure authentication scheme, but also proposed the vehicle-to-vehicle authentication scheme. We adopted ROR, AVISPA tools and rigorously informal security analysis to prove the security of the proposed scheme. In addition, we analyzed the detailed overheads and adopted NS-3 to conduct the performance analysis. Finally, the results of the security analysis, performance analysis, and comparison analysis proved the effectiveness of our proposed scheme to provide security and protection.

With the development of the mobile Internet, the UGC (User Generated Content) community has played a very important role in people's daily lives. While the traditional UGC community stores content and information centrally, user data has security risks. In addition, it lacks an effective incentive mechanism, and the user viscosity is not very high. The use of blockchain technology can not only ensure the security of users' data, but the incentive mechanism contained therein can also well empower existing communities. This paper takes the blockchain-based community Steemit as an example, and focuses on the incentive mechanism. Moreover, we propose some improvement suggestions for the shortcomings in Steemit. We hope the UGC community based on blockchain can develop better in the future.