Hermes

A peer-to-peer delay-tolerant network (DTN) overlaid on top of IP.

It strives to allow applications that can continue to work at least a century into the future. We base our design on technology that has lived for the past half-century in order to inform what might still be in use a century later. Namely, cryptographic primitives like signatures and encryption, the internet protocol (both IPv4 and IPv6), UDP, and distributed hash tables. While we strive to only assume aspects of the environment that have survived for the past half-century,

Essentially it defines a set of protocols to enable devices to send messages to one another, even if two communicating devices are never online at the same time and even if both are behind firewalls and network address translators (NATs).

This project defines protocols via a reference rust implementation and strongly typed RPC call structures. Eventually it might be codified into a proper specification but ultimately that effort will only be worthwhile to start once the reference implementation is stable.

This project defines protocols because protocols are typically designed to work between any machines adhering to the protocol, are written in any language, make minimal external assumptions about the environment, and allow for both forward and backward compatibility. This matters because the goal is to design an overlay network that can facilitate message delivery regardless of which machines are following the protocol.

Structure

Hermes consists of two node types; earth nodes and sky nodes. Earth nodes are the nodes handling the forwarding of message data with one another while Sky nodes play matchmaker, helping earth nodes find other earth nodes and facilitating the establishment of direct connections between them with NAT traversal.

License

Licensed under GPL-v3.

Credits

Hermes directly relies on the following libraries:

• minicbor and minicbor_io (licensed under the Blue Oak Model License).
• Licensed under the MIT License:
  • tokio crates:
    • tokio
    • tracing
    • bytes
• Dual licensed under MIT and Apache 2.0:
  • arrayvec
  • thiserror
  • futures crates:
    • futures
    • futures-io
  • rand
  • syn
  • quote
  • proc_macro2
  • proc-macro-crate
  • quinn
  • crypto-bigint
  • sha2

For development purposes (just to build and test, not included in the final binary) Hermes relies on several more libraries. These are specified under the [dev-dependencies] in each crate's Cargo.toml file. All dependencies of the dens (Discrete-Event Network Simulator) crate are purely used for testing.