Feature Request: Handle MegolmEvents, request keys from other sessions

[robertmx]

Dear Developers,
thank you for this nice command line utility. I have an encrypted 1on1 Chat that I would like to archive. Verification and room login has been successful. But the events received from the server are of the type "MegolmEvent", which is not handled. Any clues? I attached a sample of the event.

Message received for room XXX [XXXXX:matrix.org] | sender XXXXX [XXX] | 2021-08-06 21:28:22 | Received unknown event: MegolmEvent(source={'content': {'algorithm': 'm.megolm.v1.aes-sha2', 'ciphertext': 'AwgFEqAB8Nan2sc7IyEabZkXwKLUyz/tlrPxMwoTPHz4H8SLhuS0AD/K7DPhV1RpOJ5AgB2tobrW7CKH0trE5B7QMvp/6XcpKiSyKAWGTqsvl07rlHqGOqEPUf7PlSUtDZMvch3lYQaMHQBieSDT6+gNpJ2iiBlpdBxZlmavcCkzm8SXo3pDcL7JK9kt4GXkQLp7tWn6EJVQ2PkZnDa7MoMtfbYxd/Lo08OMXu+2Hnm83KE/xiaTyVw3cdgj3/UuGn+kUN0rWgCgCKhjID0IwMf9ldSQb1llQXc68B+Kd61l6cGtwuBkI53UpW2yCQ', 'device_id': 'LTUQENZNRX', 'sender_key': 'qxXN13jOmr4MlspZbmBqUB85FzyJuDt8m32HkLEefD0', 'session_id': 'mmsUFWpFsdxerIBDfNGhXlODh1Mhfo+TOPYyulJI3Sk'}, 'origin_server_ts': 1628278102151, 'room_id': '!rFTyESTNxkAoyZLznY:matrix.org', 'sender': 'XXXXXXX', 'type': 'm.room.encrypted', 'unsigned': {'age': 248567915}, 'event_id': '$fkJHAvQj3M_tKxZJRqvvY6kwfInGfkPwoF31E7kpcRM', 'user_id': 'XXXX', 'age': 248567915}, event_id='$fkJHAvQj3M_tKxZJRqvvY6kwfInGfkPwoF31E7kpcRM', sender='XXXXXX', server_timestamp=1628278102151, decrypted=False, verified=False, sender_key='qxXN13jOmr4MlspZbmBqUB85FzyJuDt8m32HkLEefD0', session_id='mmsUFWpFsdxerIBDfNGhXlODh1Mhfo+TOPYyulJI3Sk', transaction_id=None, device_id='LTUQENZNRX', ciphertext='AwgFEqAB8Nan2sc7IyEabZkXwKLUyz/tlrPxMwoTPHz4H8SLhuS0AD/K7DPhV1RpOJ5AgB2tobrW7CKH0trE5B7QMvp/6XcpKiSyKAWGTqsvl07rlHqGOqEPUf7PlSUtDZMvch3lYQaMHQBieSDT6+gNpJ2iiBlpdBxZlmavcCkzm8SXo3pDcL7JK9kt4GXkQLp7tWn6EJVQ2PkZnDa7MoMtfbYxd/Lo08OMXu+2Hnm83KE/xiaTyVw3cdgj3/UuGn+kUN0rWgCgCKhjID0IwMf9ldSQb1llQXc68B+Kd61l6cGtwuBkI53UpW2yCQ', algorithm='m.megolm.v1.aes-sha2', room_id='XXXX')

[robertmx]

Well I dug around somewhat and I think I understand the problem here. The MegolmEvent from matrix-nio signals, that the session key is missing. I can see all messages that are sent, after matrix-commander joins the encrypted room, because its session key is added to the recipients list. Unfortunately it is impossible to archive old messages, because matrix-commander doesn't have the required session keys.
Normally that would be handled by requesting those keys from the other active sessions or retrieving them from the key backup, which seems not implemented in matrix-commander at the moment.

[8go]

A "late" thank you @robertmx for your comments. Yes, requesting keys from other sessions is not implicitly implemented in matrix-commander. If you have the skills and time, feel free to contribute a PR for this enhancement request.

[solonovamax]

For anyone experiencing this issue, a temporary workaround is to export all your keys (in element: Settings -> Security & Privacy -> Cryptography -> Export E2EE room keys), and then import them using

matrix-commander --import-keys /path/to/the/keys 'the password' [the rest of your command]

this should allow you to decrypt all the past messages.