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---
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slug: 14
title: 14/WAKU2-MESSAGE
name: Waku v2 Message
status: draft
editor: Oskar Thorén < oskar @ status . im >
contributors:
- Sanaz Taheri < sanaz @ status . im >
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---
This specification provides a way to encapsulate messages sent over Waku with specific information security goals.
# Motivation
When using Waku to send 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.
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# WakuMessage
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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 [Waku Filter spec ](waku-filter.md ) for details.
The `version` field MAY be filled out to allow for various types of payload encryption. Omitting it means the version is 0.
## Protobuf
```protobuf
message WakuMessage {
optional bytes payload = 1;
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optional uint32 contentTopic = 2;
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optional uint32 version = 3;
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}
```
## 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.
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### Version 1 (not yet implemented in Waku v2)
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This indicates that payloads MUST be encrypted using [Waku v1 envelope data
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format spec](https://specs.vac.dev/specs/waku/v1/envelope-data-format.html).
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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.
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# 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.
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# Changelog
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Initial release on [2020-10-22 ](https://github.com/vacp2p/specs/pull/222/commits/dbab6c7084b414b62818150588266abedd09315f ).
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# Copyright
Copyright and related rights waived via
[CC0 ](https://creativecommons.org/publicdomain/zero/1.0/ ).
