Ability to export megolm keys for a given room (or sessions within a room)

[ara4n]

If a user consciously wants to share the encryption keys for a chunk of room (for whatever reason; e.g. to help a user recover their lost history, or an out-of-band way to share history from before a user joined the room), it'd be nice to have an export keys button which provided a passphrased download that the other user can import.

[ara4n]

(this is scenario 5 from element-hq/element-web#5675)

[ara4n]

This looks quite easy actually; see thread over at https://twitter.com/RiotChat/status/981940170948784131

[cyphar]

Any progress on this? Right now the only way you can do this is to export all of your keys (using the normal key export feature) and share them with a third-party, but this seems like an absolutely awful way of doing it -- while the other user might not be able to access the room you've added keys of your own rooms to their keyring.

[cyphar]

I've written a python script which allows you to do this in a really crude way (you have to download your session data and then with jq you can filter out the rooms you are interested in). The pipeline looks like this:

% megolm_backup.py --from riot-keys.py |
	jq 'map(select(.room_id == "!foo:matrix.org"))' |
	megolm_backup.py --into > new-riot-keys.txt

[a22sc]

A button in the room settings would be useful to send the enc keys of a room to all its members.
another thing could be, the user, who has lost their keys, could requests them from all members - very useful in private conversations also

[penyuan]

Is there an update on this issue or a current workaround to achieve this?

[tim-seoss]

Is there an update on this issue or a current workaround to achieve this?

cyphar's workaround worked for me last time I needed it: #1287 (comment)

[penyuan]

OK, thanks @tim-seoss I'll try @cyphar's solution for now. Still hoping that there's a better solution that will be implemented by the devs soon. This feels like a much-needed feature!