I cannot see past encrypted messages

[mrlogick]

I did a video to explain the problem:
[video]

test2.mp4

• User A logs in
• User A creates an encrypted room, writes something, and invites user B
• User A logs out
• User B logs in
• User B joins the room, but he cannot see past messages

I tried logging out and coming back with both users, but I cannot see past encrypted messages.

I think the problem is due to the fact that I tried everything within the same web browser. If I try with two computers (one for each user), with both browsers online at the same time, encrypted messages do appear.

I re-tried with my own private server (with synapse), instead of matrix.org, and even with several matrix clients, but the problem still remains.

[t3chguy]

Your issue is here

User A creates an encrypted room, writes something, and invites user B
+
with both browsers online at the same time, encrypted messages do appear.

If B doesn't have devices online at this time, then you can't send them the decryption keys for the history.
This is due to Megolm featuring PFS (Perfect Forward Secrecy)

[mrlogick]

I apologize for my poor understanding of cryptography.

In the "room settings" it is said:
Who can read history?
[*] Members only (since the point in time of selecting this option)

Also, when I'm inviting the new user Element is saying:
Invited people will be able to read old messages. (4:39 minutes of my video)

What's the point of Matrix if clients need to stay online? It should be enough that servers are online.

Is it possible to solve this?
If I already started a project, and new friends want to join my project, I need to let them see the whole history.

[t3chguy]

What's the point of Matrix if clients need to stay online?

Not online, just logged in.

When you log in you create a cryptographic keypair to which you receive encryption keys

[t3chguy]

Closing in favour of element-hq/element-meta#647 + element-hq/element-meta#1893