# Chat and direct messages

Group chat, direct messages, tags, search and notifications.

Chat in Databeamer is readable only by the people in the conversation. The server passes messages along without being able to read them.

> **Security details**
>
> - A group chat is encrypted with the group's symmetric key; a direct message uses a dedicated group for the two of you. Messages are ChaCha20-Poly1305 ciphertexts bound to the channel and message ids, and the sender signs each ciphertext with their hybrid signing key.
> - The server sees the channel, the sender, timestamps, the key version, read positions, typing and presence. Message text, tags, replies and edits are encrypted.
> - Delivery runs over a message broker that holds ciphertexts briefly so devices can catch up. Browser notifications carry the event type and recipient only.
> - A new group member can read the full history. Removing a member does not re-encrypt earlier messages; see [key rotation](https://databeamer.eu/en/docs/groups/groups#when-someone-leaves-key-rotation).

## Group chat

Every [group](https://databeamer.eu/en/docs/groups/groups) has a chat. Open it from the group's sidebar under **Chat**, or pop it out with **Open in chat window** to keep it next to your files.

## Direct messages

On desktop, direct messages live in the floating **Chats** window. On your phone they are the **Chats** tab.

- **New chat** lets you find a person by searching your contacts, public profiles and your organisation's members. Only people with a Databeamer account can be messaged.
- Filter the list by **All**, **Direct**, **Groups** or **Unread**.
- **Hide conversation** removes a direct message from your list without deleting it for the other person.

## Writing messages

- Press **Enter** to send.
- Words starting with **#** become tags. Click a tag to see every message that carries it.
- **Search messages** finds text in the messages currently loaded in the conversation.
- You see when someone is typing, and whether they are online.
- A **New messages** line marks where you left off. Deleted messages show as "This message was deleted".

## Notifications

Under **Settings › Notifications › This browser** you can enable browser notifications for **Chat messages**. They tell you who wrote and where, never what they wrote.

## What chat does not do yet

Attachments, @mentions, reactions and read receipts for other people are not available in chat. To send a file to someone, use a [transfer](https://databeamer.eu/en/docs/transfers/send-a-transfer) or [Secure Mail](https://databeamer.eu/en/docs/transfers/secure-mail).