## 3 The Meshtastic Protocol
* **Mesh Broadcast Algorithm** This layer is responsible for propagating messages through the mesh network; it plays a pivotal role in ensuring that messages reach their intended destinations, leveraging the collective capabilities of the network's nodes. The Meshtastic protocol handles network partitioning through its inherent mesh networking capabilities and the utilisation of a mesh broadcast algorithm. When a network partition occurs, the protocol's design allows for the continued operation of the network on both sides of the partition, enabling the independent evolution of each partition. This approach is known as split-brain, where each side of the partition can operate autonomously, with both sides potentially perceiving the other as having failed. The mesh broadcast algorithm, a fundamental component of the Meshtastic protocol, facilitates the propagation of messages through the mesh network. In the event of a network partition, this algorithm allows for the continued dissemination of messages within each partition, enabling the independent evolution of the network on both sides of the partition. This capability is essential for maintaining communication and data exchange within the network, even in the presence of network partitioning. The Meshtastic protocol incorporates Carrier-Sense Multiple Access with Collision Avoidance (CSMA/CA) for channel activity detection, a mechanism commonly used in WiFi. This approach requires all transmitters to perform Channel Activity Detection (CAD) before attempting to transmit, ensuring efficient channel utilisation and minimising the risk of data collisions. Furthermore, the protocol's use of Protocol Buffers ensures cross-vendor and cross-implementation compatibility, allowing devices from various manufacturers to seamlessly interoperate within the network. Additionally, the protocol integrates encryption mechanisms to secure the transmitted data, safeguarding the privacy and integrity of the communication within the mesh network. The Meshtastic protocol is designed to be adaptable to various applications and use cases, particularly in the context of IoT and mesh networking. Its efficient and reliable routing mechanisms make it well-suited for scenarios requiring long-range, low-power wireless communication, such as environmental monitoring, asset tracking, and remote sensor networks. Although Meshtastic includes robust mesh networking capabilities, it still faces challenges related to trustworthiness. Indeed, in the context of wireless mesh networks, the establishment of trust between network participants is crucial for ensuring secure and reliable communication. Several research works and discussions shed light on the significance of trust and reputation models in mitigating the effects of attacks and evaluating the trustworthiness of network entities.For instance, in [21], the authors present a study related to protocols in wireless mesh networks. They emphasise the vulnerability of IoT settings to various types of attacks, which can compromise the authenticity, integrity, and real-time delivery of data. To address these challenges, the implementation of trust and reputation models is highlighted as a means to evaluate the trustworthiness of different players in IoT settings. Additionally, discussions within the Meshtastic community highlight the potential risks and challenges related to protocol validation, circular routing, and unintended denial-of-service attacks. These discussions underscore the importance of trustworthiness and, as a consequence, the proper processing of network packets to avoid potential disruptions and security vulnerabilities. For this reason, in the next section, we present a reputation model based on reliability and reputation to address these challenges and ensure the trustworthiness and security of communication within the network with the Meshtastic protocol. Figure 1: Meshtastic protocol scheme.