Introduction to Reticulum

May 19, 2023

In my last two posts [1, 2] about Meshtastic, I mentioned how I wanted to experiment with Reticulum. Now, I'm excited to share my experience and provide an introduction to the project!

What is Reticulum

The Reticulum website provides a very rough explanation of what Reticulum is and what it does. To quote parts of it:

Reticulum is the cryptography-based networking stack
for building local and wide-area networks with readily
available hardware. Reticulum can continue to operate
even in adverse conditions with very high latency and
extremely low bandwidth.

The vision of Reticulum is to allow anyone to operate
their own sovereign communication networks, and to make
it cheap and easy to cover vast areas with a myriad of
independent, interconnectable and autonomous
networks. Reticulum is Unstoppable Networks for The
People.

Reticulum is not one network. It is a tool for building
thousands of networks. Networks without kill-switches,
surveillance, censorship and control.

Lots of important keywords here, let's explain what it all means.

  • Cryptography based: Reticulum is end-to-end-encrypted (e2ee), this means that only the sender and the receiver of a packet can read the contents of said packet. This also means that the source of a packet cannot be impersonated.

  • Readily available hardware: Reticulum is made to work over a wide range of transport protocols and mediums, from link local address or AX.25 KISS frames to I2P tunnels and LoRa PHY packets. The hardware that's supported ranges from ethernet or wifi devices to HF/VHF/UHF/etc radios and development boards with LoRa chips.

  • Interconnectable and autonomous: Reticulum networks and devices can be connected to other Reticulum networks or remain independent. The devices can be part of a mesh or have strict and predetermined topographies.

If you're still feeling lost, the gist of it is that Reticulum is a tool, in particular, a set of APIs/specs that help you build cryptography based networks over various mediums. There's a reference implementation of the network stack written in Python, along with firmware for LoRa devices, a computer application for messaging and page browsing, a mobile application and so much more.

I want to highlight the fact that this isn't a single network, but a tool to create multiple networks over different mediums. Having said that, there's currently a small testnet that works over the public internet and I2P tunnels as a way for people to easily run experiments.

Features, usecases and examples

The reticulum website has extensive documentation on every aspect of the system and explanation on how things work. It's really good. I recommend reading parts of it to get a better grip on what's possible. Here are the features and work that blew my mind:

  • Devices can request resources from other parts of the network without identifying themselves first. Revealing your identity to the other end is up to you.

  • Different networks that use different transports can be easily connected with each other. For example, connecting a network with three LoRa nodes to the testnet that uses TCP/IP, only requires a single of those LoRa nodes to be able to communicate with the testnet. The rest of the nodes or the testnet are gonna use said node as a "router".

  • A side effect of the above point, and the way Reticulum works, is that devices can move across the world, even change their network interfaces or medium and still be accessible once they find a way to rejoin the network.

  • RNode. RNode deserves a blog post on its own. It's a firmware for various LoRa development boards that enables them to act like a Swiss army knife for LoRa. From sniffing LoRa traffic all the way to being an interface for Reticulum. Moreover, they're able to self-host the RNode software and replicate it to other devices, making it easy to create more RNodes in the field.

My Reticulum journey so far

My understanding of the stack isn't complete yet. I've contributed some bug fixes to the codebase or documentation changes, but there's still a lot to learn and figure out. Some of the cool things I've tried so far include:

I've spun up some nodes on the testnet. These include both Debian hosts and OpenBSD ones for testing the build-in encryption primitives (instead of using OpenSSL).

Next, I connected my laptop to the testnet over LoRa. WiFi on my laptop was turned off and its only means of networking was by using a RNode connected to it. My desktop, which was connected to the testnet via the public internet also had a RNode device attached and acted as the "router" for the laptop. Here's a webm of my laptop connecting to a BBS-like service over LoRa.

It's not easy to spot it in the video, but this is bi-directional. I'm making requests to the BBS service over LoRa and the BBS replies back to me. This uses rnsh and the BBS is a service hosted on the testnet by acehoss, who developed rnsh.

Next, I tried replicating what Mark (the creator of Reticulum) did here. He used RNodes to SSH over LoRa, without using Reticulum but plain LoRa PHY. However, messing around with ax25 seemed a bit too troublesome to me. Rnsh on the other hand, claimed it could provide a ssh/telnet like experience over Reticulum. So, I grabbed my laptop and headed for the nearby mountain while my desktop was still connected to the testnet over TCP/IP and had a RNode attached.

Once I was near the top, I turned on the laptop, attached the RNode and tried accessing my desktop. It worked on the very first try! Almost 1.7 kilometers away from my apartment, without a clear line of sight, since one of the RNodes was inside a concrete apartment. It just worked, like radio sorcery! And it wasn't just rnsh that worked. I was able to access the testnet, as well as other people from the testnet were able to access files on my laptop node.

Next steps and work in progress

Life hasn't been kind to me for the past few months, thus some Reticulum related projects I've started were left in limbo. I do want and plan to continue working on them, I just don't know when I'll be able to spent more time on them.

  • I tried adding support for Micron, a custom markup language used for hosting pages with links in Reticulum/NomadNet to my custom Hugo theme. I need to iron out some bugs and document it to NomadNet/elsewhere.

  • I started developing a parser for Reticulum packets in Rust. This ended up being a library that can parse packets and a small CLI utility that can print them out using the library. I used this while learning both Rust and how Reticulum works. I've got a bunch of external feature requests for what the library and the CLI should do, some of these are already implemented, but I haven't completed the work yet. Personally, I would love to find the time to extend the library to a proper Reticulum library for Rust, that can both parse and create packets.

Future of Reticulum

I haven't followed the project closely in the last two months, but it seems to be gaining a lot of popularity! If you can, please support Mark, the main developer behind Reticulum, since it's obvious he's spent so much time and effort in this very polished piece of software/hardware/stack that is free for all of us to use!

Tags: hardware offgrid lora reticulum