Group communications play a crucial role in enhancing the quality of service (QoS) of Internet of Things (IoT) networks, enabling efficient information dissemination while minimizing resource utilization. However, ensuring information security and privacy in IoT group communications necessitates the implementation of an efficient and lightweight key management scheme due to the limited capabilities of most IoT devices. This paper presents a novel key management protocol for group communications that employs distributed Blockchain technology in IoT networks. The proposed scheme considers nodes belonging to multiple groups. By utilizing an asymmetric key shared among group members, secure communication is established between outsiders and group members while preserving anonymity inside the group. A distinguishing feature of the protocol is its combination of group member anonymity and automatic key revocation facilitated by a Smart Contract. Furthermore, simulation results demonstrate the efficiency of the proposed scheme, consuming less than 300 mJ of energy and taking less than 7 seconds to establish a group key among 1000 nodes, outperforming several existing approaches in the literature in terms of computation and communication costs.

The Internet of Drones (IoD) manages and coordinates communications between drones in Internet of Things (IoT) applications. Ensuring security and privacy in unmanned aerial vehicles (UAVs) networks, i.e., drones, is essential to protect data from cyber attacks. In this context, providing authentication is a major challenge due to the fact that drones are devices limited in power capabilities. The problem is aggravated by the dynamism of IoD networks due to the high mobility of drones, being sensitive to packet loss and handovers. Blockchain technology is attractive to address the problem of centralization of existing authentication protocols. In this article, we provide a decentralized, secure, and efficient authentication protocol, based on$\mu $Tesla, that relies on Blockchain to manage drone authentication. We analyze the security and performance of the proposed solution. Simulation results show that the proposed solution outperforms several approaches in the literature, achieving an authentication delay of less than 250 ms with a low information exchange of 1024 bits for 128-bit security level while maintaining low computational requirements.

Internet of Things (IoT) solutions have applications in various spheres of human life. There is a large number of IoT devices connected to the Internet and with a tendency to increase. Blockchain technology allows solving multiple security and centralization problems in these overcrowded networks. Fork occurrence affects the performance of many consensus mechanisms used in Blockchain, so it is important to analyze their performance considering different metrics and traffic patterns. This paper evaluates the performance of a blockchain-based IoT network in terms of the Age of Information (AoI) considering different traffic patterns and forking phenomena. Simulation results show that the AoI remains constant until the average time a batch stays in the queue is less than the average mining time and the decrease stops when the miners reach their maximum mining capacity. The simulation results allow to verify the agreement with the analytical model and to study the influence of the blockchain configuration parameters in the AoI, for different sensing mechanisms.

Currently, the Internet of Things (IoT) is widely used by the emerging of internet-integrated wireless devices in daily life. In order to communicate and exchange data with each other, IoT devices must pass by a gateway that belongs to the same network. But, considering the mobility of such devices and their constraints, it becomes difficult to trust and to connect from a gateway to another. Therefore, this paper introduces a blockchain-based secure handover protocol. It ensures an anonymous mutual authentication solution between a mobile IoT device and a visited gateway by using Zero-Knowledge Proof (ZKP) protocol. To do, simulations have been performed thanks to a discrete events simulator. In addition to a good security level, compared with the most used protocol (DTLS), our simulation results lead to better performance in terms of temporal complexity, energy consumption, and communication cost.

Reports of possible third-party interference in the electoral process, unauthorized voting, disenfranchisement, and technical failure raise questions about the transparency of elections around the world. At the same time, e- voting has partially replaced the traditional paper ballot-based system, with the advantages of high human labor efficiency, low cost, and low probability of error in the process. However, their use has not been extended due to the security issues of the developed solutions. Blockchain technology has been proposed to support e-voting processes to ensure the integrity, resilience and verifiability of votes, but blockchain alone is not able to guarantee the anonymity and privacy demanded by voters. In this paper, we propose a voting mechanism that uses Blockchain and a cryptographic Blind Signature protocol to guarantee anonymity and privacy to voters. The performance in terms of computational complexity and scalability is evaluated via simulation. The analysis of simulation results shows that the blockchain-based voting mechanism proposed in this paper achieves good performance in terms of computational cost and scalability.