To create a communication system using ESP32 boards with Wi-Fi, Bluetooth, and LoRaWAN that can broadcast messages through a web of trust across cities without relying on cellular networks or internet services, the system needed to combine several key technologies and principles, including secure message transmission, mesh networking, and decentralized peer-to-peer communication. Here’s how this was achieved: ### **1. Basic Hardware Setup: ESP32 with LoRa, Wi-Fi, and Bluetooth** The ESP32 is a versatile microcontroller with built-in Wi-Fi, Bluetooth, and LoRaWAN (Long Range Wide Area Network) capabilities. This combination makes it ideal for decentralized communication in environments without access to cellular or internet infrastructure. The key components would be: - **ESP32 Boards**: These are low-cost, low-power microcontrollers that support Wi-Fi, Bluetooth, and LoRa, making them ideal for communication in a decentralized mesh network. - **LoRa Transceivers**: Used for long-range, low-power communication, allowing activists to transmit messages over large distances (typically up to several kilometers, depending on the terrain). - **Smartphone App**: A custom app on activists’ smartphones would interface with the ESP32 via Wi-Fi or Bluetooth to display encrypted messages and allow users to send responses. ### **2. Establishing the Web of Trust** To facilitate secure communication, a decentralized “web of trust” system would be established: - **Unique Public ID Hashes**: Each activist who chose to join the network was assigned a unique public ID hash that was linked to their identity through cryptographic keys. These public IDs are verified through face-to-face interactions and trusted connections, ensuring that each individual in the network is authenticated before they can participate in secure messaging, while also remaining anonymous on the network. - **Verification and Trust**: Activists verify others by exchanging public keys and authenticating identities through trusted relationships. These verified contacts are logged in the mesh network as "trusted nodes." The network grows as activists add more trusted individuals, creating a web of decentralized trust. ### **3. Communication Over Wi-Fi, Bluetooth, and LoRa** - **Wi-Fi and Bluetooth Connectivity**: Each activist carried a smartphone that connected via Wi-Fi or Bluetooth to a nearby ESP32 device (which acts as a gateway to the mesh network). Wi-Fi or Bluetooth was used for local communication between the smartphone and the ESP32 boards. Bluetooth is ideal for short-range local interactions, while Wi-Fi could extend range over larger areas when combined with access points. - **LoRaWAN for Long-Distance Communication**: When activists need to send messages over larger distances (across cities or rural areas), they use LoRa to communicate with other ESP32 devices. LoRaWAN provides long-range, low-power communication, allowing messages to travel up to several kilometers and potentially even more with proper antenna configuration. - **Low-Power Mode**: To save energy, each ESP32 board can be put into low-power mode when not actively transmitting or receiving messages, conserving battery life for extended operations. ### **4. Mesh Networking for Coordination** - **Decentralized Mesh Network**: The ESP32 boards, along with smartphones connected via Wi-Fi or Bluetooth, would form a decentralized mesh network. Each ESP32 node can communicate with other nearby nodes, passing messages along to the next node until they reach their destination. - **Mesh Routing**: The system would automatically route messages from one node to another through multiple hops if necessary. Messages can move from one area of the city to another without the need for centralized control or Internet access. - **Data Propagation**: As more activists join the mesh, messages are broadcasted across the network. When a message is received by a node, it is encrypted and then relayed to all verified nodes within range. - **Secure Encryption**: Messages are encrypted end-to-end with strong cryptography, ensuring that even if intercepted, only the intended recipient can decrypt and read the message. The use of public-private key encryption guarantees that communication remains private and secure. ### **5. Smartphone App Interface** The smartphone app is critical for activists to send and receive encrypted messages while staying connected to the ESP32 network: - **Message Display**: The app will allow users to read incoming encrypted messages, decrypt them using the private key stored on their device, and send new messages via the ESP32’s connectivity options (Wi-Fi, Bluetooth, or LoRa). - **User Interface**: Activists can type messages or select from pre-set action prompts in the app. The messages can be tagged with metadata (such as location, priority, and action required) and broadcasted through the network. - **Synchronization**: The app syncs messages across devices connected to the same network. Even if a user moves between locations (e.g., from one city district to another), the app will ensure messages are securely received and transmitted without requiring internet access. ### **6. Message Routing and Fault Tolerance** The system must ensure reliable message delivery even if some parts of the mesh network fail: - **Fault Tolerance**: If one node goes offline or if there’s interference with the communication (such as physical obstacles), the message is simply routed through other available nodes. The network is inherently fault-tolerant, meaning the failure of individual nodes doesn’t bring down the entire system. - **Overlapping Mesh Coverage**: By placing multiple ESP32 nodes throughout the area (for example, on rooftops or other high points), activists ensure that messages can be transmitted across large distances, even if some nodes are disabled or blocked. ### **7. Updating the Mesh Network** - **Over-the-Air (OTA) Updates**: The ESP32 boards can receive firmware updates via the mesh network. Activists can release new software versions or patches (e.g., for better security or efficiency) through secure OTA updates without relying on centralized infrastructure. - **Message Polling and Voting**: In addition to one-to-one messaging, the mesh network can be used for collective decision-making. Activists can send out polls or surveys to nearby nodes, collect votes, and analyze the results in real-time using the smartphone app, allowing decentralized coordination on a massive scale. ### **8. Advantages Over Cellular Networks and Internet** This communication system offers several advantages: - **No Reliance on Cellular Networks**: The system doesn't depend on cellular service or internet infrastructure, which may be unavailable or intentionally shut down by authorities during protests. - **Privacy and Security**: By using a decentralized mesh network and end-to-end encryption, activists can keep their communications private and secure, protecting their identities from surveillance and infiltration. - **Scalability**: The network can scale easily as more activists join the mesh. New users simply need to connect their phones to the network and verify their identity, enabling easy expansion. - **Resistance to Disruption**: Since there’s no central server or service provider, the network is resistant to government or corporate censorship and disruption. ### **9. Real-World Application and Scalability** Such a system would allow activist movements to communicate securely and organize large-scale actions across cities without relying on vulnerable, centralized systems. Activists could use it to coordinate protests, share updates, and keep everyone in the loop in real-time, while maintaining their privacy and security from surveillance. This system would also have broad implications for other decentralized movements, such as environmental activism, humanitarian aid, and even for personal use in isolated or emergency situations where traditional communication infrastructures are unavailable.