Sync synchronize conversation history

[benpate]

When the app recognizes that a new device has been added to a user profile, it should prompt users to send their conversation history to that new device. This could use the inbox, with private messages routed only to current user. When the new device receives these messages, it can process them then delete them from the server.

[mayel]

How would you encrypt them if passing by the server? After speaking with someone from p2panda about how other apps do it I was thinking of trying something like what DeltaChat does (sending the history p2p between devices) but I guess that doesn't work for a web client? See bonfire-networks/bonfire-app#2052

[benpate]

I'm not sure how to do it. This is a placeholder to work out a plan. Here's something crazy I'm kicking around for now.

Ephemeral "self-groups" for JUST the sending and receiving devices. So..

1. I have a device already running with lots of group history.
2. I connect a new device to my account. I'm tracking devices as "generators"
3. The new device registers a KeyPackage (linked to its generator ID)
4. The new device tells me to go to my existing device and enter [this 6 digit code] to authenticate.
5. The new device creates a (MLS encrypted) group containing ONLY my own devices - no other actors - and publishes the code to it.
6. My existing device sees the KeyPackage (via SSE push? IDK.. somehow) and prompts me to enter the authentication code if I want to sync my conversation history.
7. If the codes match, my existing device starts sending messages to the (MLS encrypted) group containing all of my message history.
8. The new device receives the message history, stores it, and acknowledges receipt of each message back to the sender.
9. When the existing device receives an acknowledgement, it deletes the (MLS encrypted) messages from the server.
10. When the existing device receives an acknowledgements for every message sent, it sends a "done" message.
11. When the new device receives the "done" message, it kicks everyone from the group, and deletes the group.

Perhaps something like that, with another 6 months of refinement?