How secure are messages in Lemmy?

mythic_tartan@sh.itjust.works to Asklemmy@lemmy.ml – 9 points –

I just read this post https://lemmy.world/post/1041399 And I wonder if messages here are end to end encrypted, or readable by admins or semi- public like voting? Thanks

13

They are not secure, as it states when you try to DM someone:

This is the same as any other DM service on any site that isn't end-to-end encrypted, which are the majority. Nothing sensitive should ever be shared via DM.

As far as I know, they're readable by admins. So at least right now, if you want to use Lemmy for private communications, you have to do it manually with something like GPG. Hopefully e2e encryption on DMs gets implemented at some point.

I assume no, because public forum like Lemmy end to end encryption would be quite irrelevant feature. If you communicate secrets, you use messaging apps, not link aggregators.

DMs aren't secure but there is a great and tight integration to Matrix such that anyone privacy minded should use that feature. No need for Lemmy to reinvent that wheel.

Can you elaborate how there is any integration between Lemmy and Matrix? I haven't noticed any feature related to Matrix in Lemmy so far.

In settings on your Lemmy account accessible when you browse your home instance you can add your matrix account handle and then you get the option to send your DMs through Matrix instead to anyone that has done the same:

https://lemmy.mildgrim.com/pictrs/image/2862348f-237f-4855-b391-49d652b1c975.png

As a bonus you can self host Matrix as well :)

I see. I have honestly ignored those "Give us all your other accounts" parts in sign up and profile settings on so many websites for so long I barely even see them any more.

It is a bit of a surprise to see actual functionality attached to that.

How does it authenticate you and prevent the instance admin from sending Matrix messages in your name though? Or for that matter, how does it prevent the instance admin from reading your messages before encryption or after decryption?

It doesn't go through Lemmy at all, it sends you through Matrix if you chose that option. Just carries in the receiver nothing more. The integration is asking you if you want to send securely when that option is available by both of you having Matrix accounts and told Lemmy about them.

I see, so it basically generates the Matrix equivalent to a mailto: link?

Sounds like in that case the worst an admin could do is essentially a downgrade or MITM ttack by blocking or modifying the message that tells you about the Matrix address of the other person or the fact that they have Matrix.

Yeah, but anytime you use an instance on Lemmy you need to trust those admins. With this being open source its fairly trivial to change it for nefarious purposes while still maintaining the core functionality. Changing links to point to whatever. JavaScript changes to steal the password entered (since so many reuse passwords) etc.