mirror of https://github.com/status-im/specs.git
159 lines
7.0 KiB
Markdown
159 lines
7.0 KiB
Markdown
---
|
|
permalink: /spec/7
|
|
parent: Draft specs
|
|
title: 7/GROUP-CHAT
|
|
---
|
|
|
|
# Status Group Chat Specification
|
|
|
|
> Version: 0.1
|
|
>
|
|
> Status: Draft
|
|
>
|
|
> Authors: Andrea Maria Piana <andreap@status.im>
|
|
>
|
|
|
|
|
|
## Table of Contents
|
|
|
|
- [Abstract](#abstract)
|
|
- [Membership updates](#membership-updates)
|
|
- [Chat ID](#chat-id)
|
|
- [Signature](#signature)
|
|
- [Group membership event](#group-membership-event)
|
|
- [chat-created](#chat-created)
|
|
- [name-changed](#name-changed)
|
|
- [members-added](#members-added)
|
|
- [members-joined](#members-joined)
|
|
- [admins-added](#admins-added)
|
|
- [members-removed](#members-removed)
|
|
- [admin-removed](#admin-removed)
|
|
|
|
|
|
## Abstract
|
|
|
|
This documents describes the group chat protocol used by the status application. Pairwise encryption is used among member so a message is exchanged between each participants, similarly to a one-to-one message.
|
|
|
|
## Membership updates
|
|
|
|
Membership updates messages are used to propagate group chat membership changes. The protobuf format is described in the [Status Payload Specs](status-payload-specs.md). Here we will be describing each specific field.
|
|
|
|
The protobuf messages are:
|
|
|
|
```protobuf
|
|
// MembershipUpdateMessage is a message used to propagate information
|
|
// about group membership changes.
|
|
message MembershipUpdateMessage {
|
|
// The chat id of the private group chat
|
|
string chat_id = 1;
|
|
// A list of events for this group chat, first 65 bytes are the signature, then is a
|
|
// protobuf encoded MembershipUpdateEvent
|
|
repeated bytes events = 2;
|
|
// An optional chat message
|
|
ChatMessage message = 3;
|
|
}
|
|
|
|
message MembershipUpdateEvent {
|
|
// Lamport timestamp of the event as described in [Status Payload Specs](status-payload-specs.md#clock-vs-timestamp-and-message-ordering)
|
|
uint64 clock = 1;
|
|
// List of public keys of the targets of the action
|
|
repeated string members = 2;
|
|
// Name of the chat for the CHAT_CREATED/NAME_CHANGED event types
|
|
string name = 3;
|
|
// The type of the event
|
|
EventType type = 4;
|
|
|
|
enum EventType {
|
|
UNKNOWN = 0;
|
|
CHAT_CREATED = 1; // See [CHAT_CREATED](#chat-created)
|
|
NAME_CHANGED = 2; // See [NAME_CHANGED](#name-changed)
|
|
MEMBERS_ADDED = 3; // See [MEMBERS_ADDED](#members-added)
|
|
MEMBER_JOINED = 4; // See [MEMBER_JOINED](#member-joined)
|
|
MEMBER_REMOVED = 5; // See [MEMBER_REMOVED](#member-removed)
|
|
ADMINS_ADDED = 6; // See [ADMINS_ADDED](#admins-added)
|
|
ADMIN_REMOVED = 7; // See [ADMIN_REMOVED](#admin-removed)
|
|
}
|
|
}
|
|
```
|
|
|
|
### Payload
|
|
|
|
`MembershipUpdateMessage`:
|
|
|
|
| Field | Name | Type | Description |
|
|
| ----- | ---- | ---- | ---- |
|
|
| 1 | chat-id | `string` | The chat id of the chat where the change is to take place |
|
|
| 2 | events | See details | A list of events that describe the membership changes, in their encoded protobuf form |
|
|
| 3 | message | `ChatMessage` | An optional message, described in [Message](#message) |
|
|
|
|
`MembershipUpdateEvent`:
|
|
|
|
| Field | Name | Type | Description |
|
|
| ----- | ---- | ---- | ---- |
|
|
| 1 | clock | `uint64` | The clock value of the event |
|
|
| 2 | members | `[]string` | An optional list of hex encoded (prefixed with `0x`) public keys, the targets of the action |
|
|
| 3 | name | `name` | An optional name, for those events that make use of it |
|
|
| 4 | type | `EventType` | The type of event sent, described below |
|
|
|
|
|
|
### Chat ID
|
|
|
|
Each membership update MUST be sent with a corresponding `chatId`.
|
|
The format of this chat ID MUST be a string of [UUID](https://tools.ietf.org/html/rfc4122 ), concatenated with the hex-encoded public key of the creator of the chat, joined by `-`. This chatId MUST be validated by all clients, and MUST be discarded if it does not follow these rules.
|
|
|
|
### Signature
|
|
|
|
The signature for each event is calculated by encoding each `MembershipUpdateEvent` in its protobuf representation and prepending the bytes of the chatID, lastly the `Keccak256` of the bytes is signed using the private key by the author and added to the `events` field of MembershipUpdateMessage.
|
|
|
|
### Group membership event
|
|
|
|
Any group membership event received MUST be verified by calculating the signature as per the method described above.
|
|
The author MUST be extracted from it, if the verification fails the event MUST be discarded.
|
|
|
|
#### CHAT_CREATED
|
|
|
|
Chat created event is the first event that needs to be sent. Any event with a clock value lower then this MUST be discarded.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates and create a chat with identified by `chatId` and named `name`.
|
|
|
|
#### NAME_CHANGED
|
|
|
|
A name changed event is used by admins to change the name of the group chat.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates and MUST ensure the author of the event is an admin of the chat, otherwise the event MUST be ignored.
|
|
If the event is valid the chat name SHOULD be changed to `name`.
|
|
|
|
#### MEMBERS_ADDED
|
|
|
|
A members added event is used by admins to add members to the chat.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates and MUST ensure the author of the event is an admin of the chat, otherwise the event MUST be ignored.
|
|
If the event is valid a client MUST update the list of members of the chat who have not joined, adding the `members` received.
|
|
`members` is an array of hex encoded public keys.
|
|
|
|
#### MEMBER_JOINED
|
|
|
|
A members joined event is used by a member of the chat to signal that they want to start receiving messages from this chat.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates.
|
|
If the event is valid a client MUST update the list of members of the chat who joined, adding the signer. Any `message` sent to the group chat should now include the newly joined member.
|
|
|
|
#### ADMINS_ADDED
|
|
|
|
An admins added event is used by admins to add make other admins in the chat.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates, MUST ensure the author of the event is an admin of the chat and MUST ensure all `members` are already `members` of the chat, otherwise the event MUST be ignored.
|
|
If the event is valid a client MUST update the list of admins of the chat, adding the `members` received.
|
|
`members` is an array of hex encoded public keys.
|
|
|
|
#### MEMBER_REMOVED
|
|
|
|
A member-removed event is used to leave or kick members of the chat.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates, MUST ensure that:
|
|
- If the author of the event is an admin, target can only be themselves or a non-admin member.
|
|
- If the author of the event is not an admin, the target of the event can only be themselves.
|
|
-
|
|
If the event is valid a client MUST remove the member from the list of `members`/`admins` of the chat, and no further message should be sent to them.
|
|
|
|
#### ADMIN_REMOVED
|
|
|
|
An admin-removed event is used to drop admin privileges.
|
|
Upon receiving this event a client MUST validate the `chatId` provided with the updates, MUST ensure that the author of the event is also the target of the event.
|
|
|
|
If the event is valid a client MUST remove the member from the list of `admins` of the chat.
|