Recommend XMPP for Real-Time Communication

[haansn08]

XMPP is the IETF Internet Standard for federated instant messaging and there are clients with support for OMEMO (end-to-end encryption) for all major platforms. I think XMPP would be a good fit for the Real-Time Communication category.

See also:

• XMPP, A Comeback Story: A 20 Year Old Messaging Protocol For Robust, Private and Decentralized Communications
• How to join the Jabber network
• A social platform built upon the XMPP standard: https://movim.eu/

[dngray]

The main reason we don't is because a lot of clients don't support E2EE for all private actions.

For example some things might be encrypted with OMEMO, other things might not be like file transfers or status updates.

In general XMPP is not a very private protocol, at least from the server admin side of things: https://infosec-handbook.eu/articles/xmpp-aitm/

With Matrix really the only exposed metadata at the moment is your matrix ID @user:example.com, room nick, and what room IDs your account is in.

In the future Matrix will be moving towards a server-less mode to improve that further https://matrix.org/blog/2021/05/06/introducing-the-pinecone-overlay-network/

[haansn08]

For example some things might be encrypted with OMEMO, other things might not be like file transfers or status updates.

All clients I know of (Conversations, gajim, Dino, Siskin, Beagle) use OMEMO for file sharing. I'm not sure what you mean by 'status updates'. If you mean presence, then clients generally send whether a user is 'Available' or 'Unavailable'. There little point in end-to-end encrypting this information as the server can already see whether a client is connected to it or not.

https://infosec-handbook.eu/articles/xmpp-aitm/

It seems like all points in this article equally apply to Matrix or federated protocols in general. (There's a lot of mundane claims here presented like some kind of gotcha: 'If the clients didn’t configure end-to-end encryption for message content, server-side parties can read everything' - duh.)

With Matrix really the only exposed metadata at the moment is your matrix ID @user:example.com, room nick, and what room IDs your account is in.

The situation might even be worse for Matrix. See also this article from the disroot.org admins why they switched to XMPP from Matrix because of privacy concerns.

[dngray]

That article from Disroot is also incredibly dated. I'm pretty sure some of those things have been fixed.

The main point was they didn't like the bandwidth usage a public Matrix server requires.

[haansn08]

I'm pretty sure some of those things have been fixed.
The main point was they didn't like the bandwidth usage

If you read the article carefully the concerns were about core protocol properties. The article also does not mention bandwidth at all.
Could you explain by which criteria one should recommend Matrix and Signal but not XMPP?

[SkewedZeppelin]

I've been using XMPP for over a decade now and it largely "just works" at the end of the day with no frills.
I was super excited for Matrix back in its early days, but I still find it largely flawed today as it was back then.

XMPP clients like Conversations, Dino, and Gajim are reasonably polished these days and work out of the box.
Biggest downside is the pitiful iOS experience due to restrictions, but the Snikket client has sane defaults I hear.

You can have a compliant server with either ejabberd or prosody in under an hour if you have basic Linux sysadmin skills.
And you can run the server on any potato you want such as a first generation Raspberry Pi.
Try running Synapse on that...

The community has even been more active than ever and you can quickly jump into suitable chat rooms as listed on https://search.jabber.network.

I remember the early Matrix client (whatever it was called) literally sent your mouse coordinates when in window to the server and had Google Analytics included, largely left a sour taste in my mouth.

XMPP can trivially and seamlessly connect to any IRC room via Biboumi and can even call landlines via jmp.chat, both fullly free (as in freedom)!
Meanwhile Matrix bridges will hold you hostage.

Not to mention that Vector IM (?) has $50 million in VC funding they eventually need to pay back.

+1 for XMPP

[dngray]

If the XMPP offerings are better than last time I checked, then maybe we could look at it again. Last time I checked really only conversations.im was viable.

[ghost]

To begin with, Matrix doesn't have any decent servers, and the majority of Matrix servers have no privacy policy.

[dngray]

The major ones do, but yes smaller Matrix servers might not really bother. The same goes for XMPP though.

[ph00lt0]

It's important to emphasize https://wiki.xmpp.org/web/XMPP_E2E_Security. Only OMEMO (XEP-0384) seems a recommendable proposal.

[ph00lt0]

@lrq3000 don't want to delay your PR but might also be good to look in to this.

[dngray]

XMPP won't be added to @lrq3000's PR as that is a legacy migration PR and we're not going to extend the window further for that.

It is also worth noting we want to really limit recommendations on PG to things that have privacy related features. If we're worried about metadata and associated data with that we might want to strengthen the criteria.

At this time it looks like Matrix has some hope of reducing metadata with their P2P functionality. https://matrix.org/blog/2021/05/06/introducing-the-pinecone-overlay-network/

[haansn08]

At this time it looks like Matrix has some hope of reducing metadata with their P2P functionality.

So does XMPP by the way: https://xmpp.org/extensions/xep-0174.html

[ph00lt0]

Sounds all good, just wanted to give a heads up. I am not really in favor of adding too many things that offer less security/privacy either, but thought it's good that this is aligned and you guys have a look.

[tgkudelski]

Hello and sorry for the necroposting, but I just wanted to point out the following: The "privacy VS metadata" is a false dichotomy. Metadata does matter as much as the content of the conversation for user privacy, if not more in most cases. It's not just a minor remark. I'm not asking for any action specifically, just please keep this in mind when evaluating options, thanks :)