"Unable to decrypt message" eror when trying to read messages in an E2EE chat

[Overstuff1260]

Steps to reproduce

1. Log in in your Element Account
2. Open E2EE chat
3. Not reading anything

Outcome

What did you expect?

reading messages

What happened instead?

"unable to decrypt" error every message

Operating system

Windows 10

Browser information

Firefox 130.0

URL for webapp

app.element.io

Application version

version Element: 1.11.77 Crypto version: Rust SDK 0.7.1 (c8c9d15), Vodozemac 0.6.0

Homeserver

No response

Will you send logs?

Yes

[Overstuff1260]

probably this issue is referred to this one element-hq/element-meta#245

[strypey]

I'm having this same issue. Using chat.iridescent.nz, the community-hosted Element-web app for matrix.iridescent.nz, I created a new session, and verified it from my Android session. I'm able to access all my rooms, but in all the encrypted rooms (including DMs), all previous messages say "unable to decrypt" (including my own).

It's not out of the question that there's some user error involved. But I've been using Matrix for about 5 years and I've tried everything I can think of, done some web searching, and followed various advice on joinmatrix.org etc. Nothing has worked so far.

When the problem last happened I was using LibreWolf 130.0-3, on Fedora 40 Mate-Compiz. Today I upgraded to LibreWolf 130.0.1-1, from the Fedora repos. If there's any more info I can supply to help you track down the bug, please let me know.

[richvdh]

@strypey: please send debug logs from within the application, and from your android device. I suggest creating a new issue, so that it doesn't get mixed up with @dav9597's issues.

@dav9597: I see your debug logs, but please give more info. Does this affect newly-received messages, or only ones sent before you logged in? Did you verify your session after login? Do you have any other devices (eg mobile, other element-web sessions)?

[Overstuff1260]

Hi, my answers:

• Does this affect newly-received messages, or only ones sent before you logged in? I haven't really checked this, now I noticed that an user replied to my message in an E2EE chat, and I can see it probably because he replied directly to mine, not sure. However I attached updated logs, hope this helps
  logs.zip

Did you verify your session after login? Yes, I did

Do you have any other devices (eg mobile, other element-web sessions)? Yes, as specified in log's note, I have a Brave Chromium session too with same errors, of course web access

[Overstuff1260]

changed username per personal reasons, but it's still me

[richvdh]

It sounds like you are seeing expected behaviour.

In general, you will not be able to decrypt messages sent before you logged in. This is rather the point of end-to-end encryption: if you can see history simply by logging in, then an attacker would also be able to do so.

The exception to this is when you have a second device which does successfully receive the message keys. In that case, the other device can encrypt the message keys and upload them to a server-side storage area, where they can be retrieved by another device. However, if all your devices have the same problem (they were created after the messages were sent), that doesn't help.

There is a plan to improve this with device dehydration, but that is several months away.

[strypey]

Thanks @richvdh, done; #28116