New DMs are no longer encrypted (?)

[cyrneko]

Describe the bug

It seems that, under some circumstances, new DMs opened with users are no longer created with End-To-End-Encryption by default.

The exact requirements are unknown currently, but I've noticed that some users that DM'd me from the Cinny rooms had encryption disabled and @voxel:nope.chat has personally observed their new DMs no longer being encrypted since recently

Reproduction

1. Click on someone's profile and click "message" to start a new DM
2. Check whether Encryption is enabled (or have the recipient check)
3. Observe that E2EE is disabled, the corresponding state event did not get sent.

Expected behavior

Cinny should enable End-To-End-Encryption when possible for new Direct Messages.

Platform and versions

1. OS: Linux Kernel 6.1 on Void Linux
2. LibreWolf 136.0-2, Flatpak
3. Cinny Version: ~4.4.0+
4. Matrix homeserver: thomcat.rocks, nope.chat

Additional context

I have not yet done a git bisect to trace back when the issue started occurring, but I have this feeling it's gonna be around the same time the Vodozemac migration took place, i.e the last few versions.

[poggingfish]

I dont think this is a flaw as E2EE cannot be disabled once its enabled. Meaning it should be off by default, correct?

[cyrneko]

E2EE is not as strict as you think, clients can still simply decide to send unencrypted events (like reactions for instance) even if E2EE was enabled in a room

That said, this would still be a regression compared to previous behavior and overall would reduce security and privacy for end-users.

[voxelized-voxel]

Hey 👋, Voxel here.

My plattform and versions:

1. OS: Linux Kernel 6.8 on Linux Mint 22.1
2. Brave v1.76.74
3. Cinny Version: 4.5.1
4. Matrix homeserver: nope.chat (mine), thomcat.rocks, grapheneos.org, unredacted.org, matrix.org 

[Danfro]

Just by coincidence stumbled upon #2004 which seems to be related.

I realised that recently too, that new 1:1 rooms are not encrypted by default. But this seems to make sense somehow, since going e2e is possible, but going back not that easy.

I would wish to have a clear indication in the room list that shows if a room is encrypted or not. If encryption is desired, it can be quickly turned on.