Thomas has built a secure communications network leveraging the plug-and-play qualities of the Raspberry Pi 4 and the Adafruit LoRa Radio Bonnet. It is the software side of this system that really turns these parts into something useful.

Rather than a simple point-to-point radio link, a mesh network is built up of any transceivers in range, extending the maximum distance a message can be sent, and building in resilience in case a node goes down. Each node is connected to a PC via Ethernet, and messages are distributed via a “controlled flooding” algorithm that aims to reduce unnecessary network congestion from the blind re-transmission of messages that have already been received.

Security is handled via RSA encryption with 256-byte public/private keys and additional SHA256 hashes for authentication.

See more on Hackaday and the project on hackaday.io.