AirChat

AirChat is a proof-of-concept communication system that works without the internet or cellular networks, using audio over radio links to move messages between nodes. It couples a lightweight packet format with asymmetric keys to enable addressed delivery, optional end-to-end encryption, and anonymous broadcast when encryption is disabled. The software talks to modem software such as FLDigi via XML-RPC, letting one machine handle radio I/O while others run the AirChat service, and it can also ride any device capable of transmitting audio, including low-cost handheld radios. The design intentionally trades bandwidth for freedom, resilience, and low cost, prioritizing operation during blackouts, disasters, censorship events, or remote expeditions. Gateways allow a participating node with connectivity to bridge traffic to limited internet services like news fetching or posting updates, optionally through Tor and proxy support.