rfc/content/docs/rfcs/14/README.md

---
slug: 14
title: 14/WAKU2-MESSAGE
name: Waku v2 Message
status: draft
editor: Oskar Thorén <oskar@status.im>
contributors:
  - Sanaz Taheri <sanaz@status.im>
---

This specification provides a way to encapsulate messages sent over Waku with specific information security goals.

# Motivation

When sending messages over Waku there are multiple concerns:
- We may have a separate encryption layer as part of our application
- We may want to provide efficient routing for resource restricted devices
- We may want to provide compatibility with Waku v1 envelopes
- We may want payloads to be encrypted by default
- We may want to provide unlinkability for metadata protection

This specification attempts to provide for these various requirements.

# WakuMessage

A `WakuMessage` is what is being passed around by the other protocols, such as WakuRelay, WakuStore, and WakuFilter.

The `payload` field SHOULD contain whatever payload is being sent. See section below on payload encryption.

The `contentTopic` field SHOULD be filled out to allow for content-based filtering.
See [12/WAKU2-FILTER](/spec/12) and [13/WAKU2-STORE](/spec/13) for details.

The `version` field MAY be filled out to allow for various types of payload encryption.
Omitting it means the version is 0.

The `proof` field MAY be filled out to allow for filtering spam messages. See [Waku RLN-Relay](../17/README.md) for details.
## Protobuf

```protobuf
message WakuMessage {
  optional bytes payload = 1;
  optional uint32 contentTopic = 2;
  optional uint32 version = 3;
  optional double proof = 21;
}
```

## Payload encryption

Payload encryption depends on the `version` field.

### Version 0

This indicates that the payload SHOULD be either unencrypted or that encryption is done at a separate layer outside of Waku.

### Version 1

This indicates that payloads MUST be encrypted using [7/WAKU-DATA envelope data format spec](/spec/7).

This provides for asymmetric and symmetric encryption.
Key agreement is out of band.
It also provides an encrypted signature and padding for some form of unlinkability.

# Differences from Whisper / Waku v1 envelopes

In Whisper and Waku v1, an envelope contains the following fields: `expiry, ttl, topic, data, nonce`.

Since Waku v2 is using libp2p PubSub, some of these fields can be dropped.
The previous `topic` field corresponds to `contentTopic`.
The previous `data` field corresponds to the `payload` field.

# Security Consideration

In Waku, the confidentiality, integrity, and authenticity of the data must be addressed at the `WakuMessage` level.
That is, the `payload` shall be encrypted or signed properly to meet the application-specific privacy needs.

# Copyright

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