rfc/specs/waku/waku-v2.md

---
title: Waku
version: 2.0.0-alpha0
status: Raw
authors: Oskar Thorén <oskar@status.im>
---

**NOTE: This is a very early raw version of Waku v2 over libp2p**

## General notes and TODOs

### General
In general, we want to remove as much as possible. WakuSub should be a thin layer on top of PubSub.

A good question to ask: what is the minimal subset we have to support?

How can we defer specific properties to other protocols?

### Data field
Can we assume data field stays the same? There is nothing in data field about RLPx AFAICT:
https://github.com/vacp2p/specs/blob/master/specs/waku/envelope-data-format.md

### How do we deal with PoW etc?
If basically only full nodes set PoW to 0 then it be fine. But if light nodes also set this (afair they do) we have a compatibility issue. Though we also have mailservers.

Simplest might might be to basically send both envelopes, just take out the data thing:
- v1 [ expiry ttl topic data nonce ]
- v2 [ ... data ... ]

### Get rid of privileged point of node for RPC?
We could have JSON RPC for now and then use alt method later. We need to make
sure the interface with Stimbus and Core/Desktop makes sense.

It'd be useful if a node in browser could use another node without giving away
private keys (WalletConnect, e.g.).

### Are filters a useful abstraction?
Not sure I like this filter businesss, just deliver on a topic. If we want to do
that it can be done separately with a shim and have that specified at a
different layer. Removing coupling of routing and crypto.

### Consumer spec
Consumer: https://specs.status.im/spec/10

### Factoring out
Separate out into constituent pieces, keep main spec small here. What are the pieces?
- RPC/Node API
- Filter shim / crypto key compatibility
- Data field
- Waku v1 bridge 

### App topics and waku topics
Ensure path forward for sharding topics. See Eth2 networking spec too.

Ensure topic interest in payload (not for routing, only edge nodes). Current Waku topics.

### Clarity of purpose
Make it very clear what we provide over e.g. FloodSub.
- Privacy, resource restriction (offline, topic interest, etc)
- Thin layer on top of PubSub

## Table of Contents

TODO

## Abstract

Waku is a privacy-preserving peer-to-peer messaging protocol for resource restricted devices. It implements PubSub in libp2p and adds capabilities on top of it. These capabilities are: (i) retrieving historical messages for mostly-offline devices (ii) adaptive nodes, allowing for heterogenerous nodes to contribute, and (iii) bandwidth preservation for light nodes. This makes it ideal for running a p2p protocol on mobile.

Historically, it has its roots in Waku v1 [xx5], which stems from Whisper [xx6], originally part of the Ethereum stack. However, Waku v2 acts more as a thin wrapper for PubSub and has a different API. It is implemented in an iterative manner where initial focus is on porting essential functionality to libp2p. See here for a rough road map [xx7].

## Motivation

TODO

*NOTE: Should elaborate on privacy-preserving messaging for resource restricted devices, etc. Also Waku v1 history briefly.*

## Definitions

TODO

## Underlying Transports and Prerequisites

TODO Right now this is more like a set of components

### Peer Discovery

WakuSub and PubSub don't provide an peer discovery mechanism. This has to be provided for by the environment.

### PubSub interface

Waku v2 is implementing the PubSub interface in Libp2p. See PubSub spec [xx2] for more details.

### Protocol Identifier

The current protocol identifier is: `/wakusub/0.0.1` [xx1].

**TODO Update to 2.0.0-alpha0**

### FloodSub

WakuSub is currently a subprotocol of FloodSub. Future versions of WakuSub will support GossipSub 1 [xx3] and GossipSub 1.1 [xx4].

### Bridge mode

To maintain compatibility with Waku v1, a bridge mode can be achieved. See separate spec.

TODO Detail this in a separate spec

## Wire Specification

We are using protobuf RPC messages between peers. Here's what a message looks like, as defined in the PubSub interface.


*NOTE: Should contain protobuf definitions that cover essentials of Waku v1. In cases where it doesn't cover, we can defer to siblings/child specs, e.g. such as the data field for encryption, etc.*

### Messages

```
message Message {
	optional string from = 1;
	optional bytes data = 2;
	optional bytes seqno = 3;
	repeated string topicIDs = 4;
	optional bytes signature = 5;
	optional bytes key = 6;
}
```

TODO Detail options and what's in data, additional methods, etc

### SubOpts

TODO

## Changelog

TODO

## Copyright

Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).

## References

xx1: https://docs.libp2p.io/concepts/protocols/

xx2: [PubSub interface for libp2p (r2, 2019-02-01)](https://github.com/libp2p/specs/blob/master/pubsub/README.md)

xx3: https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.0.md

xx4: https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.1.md

xx5: specs.vac.dev/waku/waku.html

xx6: https://eips.ethereum.org/EIPS/eip-627

xx7: https://vac.dev/waku-v2-plan