Reticulum/README.md

Reticulum Network Stack β
==========

<p align="center"><img width="200" src="https://unsigned.io/wp-content/uploads/2022/03/reticulum_logo_512.png"></p>

Reticulum is the cryptography-based networking stack for wide-area networks
built on readily available hardware. It can operate even with very high latency
and extremely low bandwidth. Reticulum allows you to build wide-area networks
with off-the-shelf tools, and offers end-to-end encryption and connectivity,
initiator anonymity, autoconfiguring cryptographically backed multi-hop
transport, efficient addressing, unforgeable delivery acknowledgements and
more.

The vision of Reticulum is to allow anyone to be their own network operator,
and to make it cheap and easy to cover vast areas with a myriad of independent,
inter-connectable and autonomous networks. Reticulum **is not** *one* network.
It is **a tool** for building *thousands of networks*. Networks without
kill-switches, surveillance, censorship and control. Networks that can freely
interoperate, associate and disassociate with each other, and require no
central oversight. Networks for human beings. *Networks for the people*.

Reticulum is a complete networking stack, and does not rely on IP or higher
layers, but it is possible to use IP as the underlying carrier for Reticulum.
It is therefore trivial to tunnel Reticulum over the Internet or private IP
networks.

Having no dependencies on traditional networking stacks frees up overhead that
has been used to implement a networking stack built directly on cryptographic
principles, allowing resilience and stable functionality, even in open and
trustless networks.

No kernel modules or drivers are required. Reticulum runs completely in
userland, and can run on practically any system that runs Python 3.

## Read The Manual
The full documentation for Reticulum is available at [markqvist.github.io/Reticulum/manual/](https://markqvist.github.io/Reticulum/manual/).

You can also [download the Reticulum manual as a PDF](https://github.com/markqvist/Reticulum/raw/master/docs/Reticulum%20Manual.pdf)

For more info, see [unsigned.io/projects/reticulum](https://unsigned.io/projects/reticulum/)

## Notable Features
- Coordination-less globally unique addressing and identification
- Fully self-configuring multi-hop routing
- Complete initiator anonymity, communicate without revealing your identity
- Asymmetric X25519 encryption and Ed25519 signatures as a basis for all communication
- Forward Secrecy with ephemeral Elliptic Curve Diffie-Hellman keys on Curve25519
- Reticulum uses the [Fernet](https://github.com/fernet/spec/blob/master/Spec.md) specification for on-the-wire / over-the-air encryption
  - Keys are ephemeral and derived from an ECDH key exchange on Curve25519
  - AES-128 in CBC mode with PKCS7 padding
  - HMAC using SHA256 for authentication
  - IVs are generated through os.urandom()
- Unforgeable packet delivery confirmations
- A variety of supported interface types
- An intuitive and easy-to-use API
- Reliable and efficient transfer of arbitrary amounts of data
  - Reticulum can handle a few bytes of data or files of many gigabytes
  - Sequencing, transfer coordination and checksumming are automatic
  - The API is very easy to use, and provides transfer progress
- Lightweight, flexible and expandable Request/Response mechanism
- Efficient link establishment
  - Total bandwidth cost of setting up an encrypted link is 3 packets totaling 265 bytes
  - Low cost of keeping links open at only 0.44 bits per second

## Examples of Reticulum Applications
If you want to quickly get an idea of what Reticulum can do, take a look at the
following resources.

- [LXMF](https://github.com/markqvist/lxmf) is a distributed, delay and disruption tolerant message transfer protocol built on Reticulum
- For an off-grid, encrypted and resilient mesh communications platform, see [Nomad Network](https://github.com/markqvist/NomadNet)
- The Android, Linux and macOS app [Sideband](https://unsigned.io/sideband) has a graphical interface and focuses on ease of use.

## Where can Reticulum be used?
Over practically any medium that can support at least a half-duplex channel
with 500 bits per second throughput, and an MTU of 500 bytes. Data radios,
modems, LoRa radios, serial lines, AX.25 TNCs, amateur radio digital modes,
WiFi and Ethernet devices, free-space optical links, and similar systems are
all examples of the types of physical devices Reticulum can use.

An open-source LoRa-based interface called
[RNode](https://markqvist.github.io/Reticulum/manual/hardware.html#rnode) has
been designed specifically for use with Reticulum. It is possible to build
yourself, or it can be purchased as a complete transceiver that just needs a
USB connection to the host.

Reticulum can also be encapsulated over existing IP networks, so there's
nothing stopping you from using it over wired Ethernet, your local WiFi network
or the Internet, where it'll work just as well. In fact, one of the strengths
of Reticulum is how easily it allows you to connect different mediums into a
self-configuring, resilient and encrypted mesh, using any available mixture of
available infrastructure.

As an example, it's possible to set up a Raspberry Pi connected to both a LoRa
radio, a packet radio TNC and a WiFi network. Once the interfaces are
configured, Reticulum will take care of the rest, and any device on the WiFi
network can communicate with nodes on the LoRa and packet radio sides of the
network, and vice versa.

## How do I get started?
The best way to get started with the Reticulum Network Stack depends on what
you want to do. For full details and examples, have a look at the 
[Getting Started Fast](https://markqvist.github.io/Reticulum/manual/gettingstartedfast.html) 
section of the [Reticulum Manual](https://markqvist.github.io/Reticulum/manual/).

To simply install Reticulum and related utilities on your system, the easiest way is via pip:

```bash
pip3 install rns
```

On Arch Linux it is also possible to install using the `python-rns` package from the [AUR](https://aur.archlinux.org/packages/python-rns).

You can then start any program that uses Reticulum, or start Reticulum as a
system service with [the rnsd utility](https://markqvist.github.io/Reticulum/manual/using.html#the-rnsd-utility).

When first started, Reticulum will create a default configuration file,
providing basic connectivity to other Reticulum peers that might be locally
reachable. The default config file contains a few examples, and references for
creating a more complex configuration.

For more detailed examples on how to expand communication over many mediums such 
as packet radio or LoRa, serial ports, or over fast IP links and the Internet using 
the UDP and TCP interfaces, take a look at the [Supported Interfaces](https://markqvist.github.io/Reticulum/manual/interfaces.html) 
section of the [Reticulum Manual](https://markqvist.github.io/Reticulum/manual/).

## Included Utilities
Reticulum includes a range of useful utilities for managing your networks, 
viewing status and information, and other tasks. You can read more about these 
programs in the [Included Utility Programs](https://markqvist.github.io/Reticulum/manual/using.html#included-utility-programs) 
section of the [Reticulum Manual](https://markqvist.github.io/Reticulum/manual/).

- The system daemon `rnsd` for running Reticulum as an always-available service
- An interface status utility called `rnstatus`, that displays information about interfaces
- The path lookup and management tool `rnpath` letting you view and modify path tables
- A diagnostics tool called `rnprobe` for checking connectivity to destinations
- A simple file transfer program called `rncp` making it easy to copy files to remote systems
- The remote command execution program `rnx` let's you run commands and
  programs and retrieve output from remote systems

All tools, including `rnx` and `rncp`, work reliably and well even over very
low-bandwidth links like LoRa or Packet Radio.

## Supported interface types and devices

Reticulum implements a range of generalised interface types that covers most of
the communications hardware that Reticulum can run over. If your hardware is
not supported, it's relatively simple to implement an interface class. I will
gratefully accept pull requests for custom interfaces if they are generally
useful.

Currently, the following interfaces are supported:

- Any Ethernet device
- LoRa using [RNode](https://unsigned.io/projects/rnode/)
- Packet Radio TNCs (with or without AX.25)
- KISS-compatible hardware and software modems
- Any device with a serial port
- TCP over IP networks
- UDP over IP networks
- External programs via stdio or pipes
- Custom hardware via stdio or pipes

## Performance
Reticulum targets a *very* wide usable performance envelope, but prioritises
functionality and performance over low-bandwidth mediums. The goal is to
provide a dynamic performance envelope from 250 bits per second, to 1 gigabit
per second on normal hardware.

Currently, the usable performance envelope is approximately 500 bits per second
to 20 megabits per second, with physical mediums faster than that not being
saturated. Performance beyond the current level is intended for future
upgrades, but not highly prioritised at this point in time.

## Current Status
Reticulum should currently be considered beta software. All core protocol
features are implemented and functioning, but additions will probably occur as
real-world use is explored. There will be bugs. The API and wire-format can be
considered relatively stable at the moment, but could change if warranted.

## Development Roadmap
- Version 0.4.0
  - Improving [the manual](https://markqvist.github.io/Reticulum/manual/) with sections specifically for beginners
  - Performance and memory optimisations
  - Utilities for managing identities, signing and encryption
  - User friendly interface configuration tool
  - Support for radio and modem interfaces on Android
  - More interface types for even broader compatibility
    - Plain ESP32 devices (ESP-Now, WiFi, Bluetooth, etc.)
    - More LoRa transceivers
    - IR Transceivers
- Planned, but not yet scheduled
  - OpenWRT support
  - Metric-based path selection
  - Distributed Destination Naming System
  - Network-wide path balancing
  - Globally routable multicast
  - Bindings for other programming languages
  - Multiple paths in path table for quick recovery on link failures
  - A portable Reticulum implementation in C, see [#21](https://github.com/markqvist/Reticulum/discussions/21)
  - Easy way to share interface configurations, see [#19](https://github.com/markqvist/Reticulum/discussions/19)
  - More interface types
    - AT-compatible modems
    - AWDL / OWL
    - HF Modems
    - CAN-bus
    - ZeroMQ
    - MQTT
    - SPI
    - i²c
    - Tor

## Dependencies
The installation of the default `rns` package requires the dependencies listed
below. Almost all systems and distributions have readily available packages for
these dependencies, and when the `rns` package is installed with `pip`, they
will be downloaded and installed as well.

- [PyCA/cryptography](https://github.com/pyca/cryptography)
- [netifaces](https://github.com/al45tair/netifaces)
- [pyserial](https://github.com/pyserial/pyserial)

On more unusual systems, and in some rare cases, it might not be possible to
install or even compile one or more of the above modules. In such situations,
you can use the `rnspure` package instead, which require no external
dependencies for installation. Please note that the contents of the `rns` and
`rnspure` packages are *identical*. The only difference is that the `rnspure`
package lists no dependencies required for installation.

No matter how Reticulum is installed and started, it will load external
dependencies only if they are *needed* and *available*. If for example you want
to use Reticulum on a system that cannot support
[pyserial](https://github.com/pyserial/pyserial), it is perfectly possible to
do so using the `rnspure` package, but Reticulum will not be able to use
serial-based interfaces. All other available modules will still be loaded when
needed.

**Please Note!** If you use the `rnspure` package to run Reticulum on systems
that do not support [PyCA/cryptography](https://github.com/pyca/cryptography),
it is important that you read and understand the [Cryptographic
Primitives](#cryptographic-primitives) section of this document.

## Public Testnet
If you just want to get started experimenting without building any physical
networks, you are welcome to join the Unsigned.io RNS Testnet. The testnet is
just that, an informal network for testing and experimenting. It will be up
most of the time, and anyone can join, but it also means that there's no
guarantees for service availability.

The testnet runs the very latest version of Reticulum (often even a short while
before it is publicly released). Sometimes experimental versions of Reticulum
might be deployed to nodes on the testnet, which means strange behaviour might
occur. If none of that scares you, you can join the testnet via either TCP or
I2P. Just add one of the following interfaces to your Reticulum configuration
file:

```
# TCP/IP interface to the Dublin Hub
  [[RNS Testnet Dublin]]
    type = TCPClientInterface
    enabled = yes
    target_host = dublin.connect.reticulum.network
    target_port = 4965

# TCP/IP interface to the Frankfurt Hub
  [[RNS Testnet Frankfurt]]
    type = TCPClientInterface
    enabled = yes
    target_host = frankfurt.connect.reticulum.network
    target_port = 5377

# Interface to I2P Hub A
  [[RNS Testnet I2P Hub A]]
    type = I2PInterface
    enabled = yes
    peers = mrwqlsioq4hoo2lmeeud7dkfscnm7yxak7dmiyvsrnpfag3z5tsq.b32.i2p

# Interface to I2P Hub B
  [[RNS Testnet I2P Hub B]]
    type = I2PInterface
    enabled = yes
    peers = iwoqtz22dsr73aemwpw7guocplsjjoamyl7sogj33qtcd6ds4mza.b32.i2p
```

The testnet also contains a number of [Nomad Network](https://github.com/markqvist/nomadnet) nodes, and LXMF propagation nodes.

## Support Reticulum
You can help support the continued development of open, free and private communications systems by donating via one of the following channels:

- Monero:
 ```
  84FpY1QbxHcgdseePYNmhTHcrgMX4nFfBYtz2GKYToqHVVhJp8Eaw1Z1EedRnKD19b3B8NiLCGVxzKV17UMmmeEsCrPyA5w
  ```
- Ethereum
  ```
  0x81F7B979fEa6134bA9FD5c701b3501A2e61E897a
  ```
- Bitcoin
  ```
  3CPmacGm34qYvR6XWLVEJmi2aNe3PZqUuq
  ```
- Ko-Fi: https://ko-fi.com/markqvist

Are certain features in the development roadmap are important to you or your
organisation? Make them a reality quickly by sponsoring their implementation.

## Cryptographic Primitives
Reticulum uses a simple suite of efficient, strong and modern cryptographic
primitives, with widely available implementations that can be used both on
general-purpose CPUs and on microcontrollers. The necessary primitives are:

- Ed25519 for signatures
- X22519 for ECDH key exchanges
- HKDF for key derivation
- Modified Fernet for encrypted tokens
  - AES-128 in CBC mode
  - HMAC for message authentication
  - No Fernet version and timestamp fields
- SHA-256
- SHA-512

In the default installation configuration, the `X25519`, `Ed25519` and
`AES-128-CBC` primitives are provided by [OpenSSL](https://www.openssl.org/)
(via the [PyCA/cryptography](https://github.com/pyca/cryptography) package).
The hashing functions `SHA-256` and `SHA-512` are provided by the standard
Python [hashlib](https://docs.python.org/3/library/hashlib.html). The `HKDF`,
`HMAC`, `Fernet` primitives, and the `PKCS7` padding function are always
provided by the following internal implementations:

- [HKDF.py](RNS/Cryptography/HKDF.py)
- [HMAC.py](RNS/Cryptography/HMAC.py)
- [Fernet.py](RNS/Cryptography/Fernet.py)
- [PKCS7.py](RNS/Cryptography/PKCS7.py)


Reticulum also includes a complete implementation of all necessary primitives
in pure Python. If OpenSSL & PyCA are not available on the system when
Reticulum is started, Reticulum will instead use the internal pure-python
primitives. A trivial consequence of this is performance, with the OpenSSL
backend being *much* faster. The most important consequence however, is the
potential loss of security by using primitives that has not seen the same
amount of scrutiny, testing and review as those from OpenSSL.

If you want to use the internal pure-python primitives, it is **highly
advisable** that you have a good understanding of the risks that this pose, and
make an informed decision on whether those risks are acceptable to you.

Reticulum is relatively young software, and should be considered as such. While
it has been built with cryptography best-practices very foremost in mind, it
_has not_ been externally security audited, and there could very well be
privacy or security breaking bugs. If you want to help out, or help sponsor an
audit, please do get in touch.

## Acknowledgements & Credits
Reticulum can only exist because of the mountain of Open Source work it was
built on top of, the contributions of everyone involved, and everyone that has
supported the project through the years. To everyone who has helped, thank you
so much.

A number of other modules and projects are either part of, or used by
Reticulum. Sincere thanks to the authors and contributors of the following
projects:

- [PyCA/cryptography](https://github.com/pyca/cryptography), *BSD License*
- [Pure-25519](https://github.com/warner/python-pure25519) by [Brian Warner](https://github.com/warner), *MIT License*
- [Pysha2](https://github.com/thomdixon/pysha2) by [Thom Dixon](https://github.com/thomdixon), *MIT License*
- [Python-AES](https://github.com/orgurar/python-aes) by [Or Gur Arie](https://github.com/orgurar), *MIT License*
- [Curve25519.py](https://gist.github.com/nickovs/cc3c22d15f239a2640c185035c06f8a3#file-curve25519-py) by [Nicko van Someren](https://gist.github.com/nickovs), *Public Domain*
- [I2Plib](https://github.com/l-n-s/i2plib) by [Viktor Villainov](https://github.com/l-n-s)
- [PySerial](https://github.com/pyserial/pyserial) by Chris Liechti, *BSD License*
- [Netifaces](https://github.com/al45tair/netifaces) by [Alastair Houghton](https://github.com/al45tair), *MIT License*
- [Configobj](https://github.com/DiffSK/configobj) by Michael Foord, Nicola Larosa, Rob Dennis & Eli Courtwright, *BSD License*
- [Six](https://github.com/benjaminp/six) by [Benjamin Peterson](https://github.com/benjaminp), *MIT License*
- [Umsgpack.py](https://github.com/vsergeev/u-msgpack-python) by [Ivan A. Sergeev](https://github.com/vsergeev)
- [Python](https://www.python.org)