Hop

Hop is a delay-tolerant mesh networking protocol designed to enable encrypted datagram delivery across devices, even in environments with unreliable or intermittent connectivity. It addresses the challenge of transmitting data where no stable network path exists, such as in disaster scenarios, off-grid sensor deployments, or regions with limited infrastructure. By using a store-and-forward approach, Hop ensures that messages are held securely on nearby devices and re-offered during subsequent encounters until successful delivery is achieved, eliminating the need for cellular towers or central servers.

The protocol operates by spraying copies of each datagram across independent routes, increasing the likelihood that at least one will reach its intended recipient. If a link goes down, Hop simply relies on another available path, ensuring that messages are never dropped but persist in transit until a viable route is found. End-to-end encryption is a core feature, with datagrams hopping device to device over Bluetooth Low Energy (BLE), Wi-Fi, and internet connections. The core protocol is platform-agnostic, moving only bytes, while thin per-platform drivers handle radio communication. This design allows Hop to serve as a single transport layer for a variety of offline applications, including messaging, data synchronization, file transfer, offline web access, telemetry, and alerting.

Hop is intended for developers and organizations building applications that must function in the absence of reliable connectivity. The protocol is demonstrated in-browser, with the hop-core compiled to WebAssembly for simulation purposes.