It's quite critical of some of the code quality of common implementations as well as the fracturing across different clients.
As for Matrix, probably element is the main client you want to use. I use Nheko on Linux.
He keeps criticizing one client while trying to pass it off as criticism of the specification (said client doesn't even implement the latest version of the specification, either), complains about the protocol changing too much and the protocol changing too little, and to top it off seems to promote Signal as the better alternative, completely missing the elephant in the room -- Signal being centralized with its decisions even more whimsical at the hands of one group only. Curiously, he does that right after criticizing omemo's choice to follow Signal's choices as lacking justification.
There are two major problems, the implementations and the fact the spec isn't specific. I'm not particularly bothered by the imaginary, the dude is a furry what do you expect? Some furry bloggers do have pictures throughout their blog posts to split things up and lighten things.
As for the reply from the spec author, I had a negative opinion of that. To me it looks like they just tried to copy signal's encryption so that people could claim that XMPP has E2EE, without any real design or thought of the implementation.
One of the other things I hate about XMPP (and you mentioned it above with the jingle debacle), but there are other cases where there's multiple XEPs for the same thing. Some of them are widely used despite being marked as "experimental". The documents are not cohesive and is a mess which is probably why the implementations are also bad (unlike the Matrix spec). Encryption is just another one of those things, just like file transfer.
If I was deciding on a new project to develop a client for XMPP would be the least attractive project for me to work on. Put it that way. Without enthusiastic developers that think this thing sounds cool there simply won't be any good software.
The other thing also not mentioned is that the OMEMO encryption only applies to text messages and not all the other things, ie VOIP, status changes etc.
There is a fair bit of metadata on the server side
https://web.archive.org/web/20211215132539/https://infosec-h...
and attacks like this are just downright scary
https://notes.valdikss.org.ru/jabber.ru-mitm/
I used to use XMPP but haven't in about a decade. Nobody I know uses it either. (Even the couple of evangelists I knew moved to Matrix long ago)
Lighten things? Are you saying that putting images of cartoon characters puking at the logos of your product lightens things and provokes healthy discussion? Don't try to make this into thinking I'm criticizing furriness -- it's definitely not about that.
> There is a fair bit of metadata on the server side
This is much less critical when the protocol is federated. Even E2EE itself may become second priority rather than first in such an environment.
> Without enthusiastic developers that think this thing sounds cool there simply won't be any good software.
This is a ridiculous statement.
False. Federated protocols typically have a lot more, as there is routing data between servers. The same goes for things like Matrix.
The only thing that Matrix servers can see however realistically is the room id, and other participants. Unlike XMPP where they can copy your roster. In the case of ejabberd debug logs can include your password lol (or at least could in November 2021). I doubt that's changed.
This isn't always the case, not every user is a server admin. Also for group chats other server admins will certainly know what data your requesting.
TLDR is that XMPP is not a private protocol, and that was never its intention. It was actually very centralized in it's original usage and the designers clearly envisaged similar usage to email ie $companyA.com employees talking to $companyB.com not some sort of "private messenger" competitor to Matrix or Signal which were meant to be used by the wider general population.
> Leaking metadata to a centralized service is simply inevitable by pure physics
Not necessarily true https://signal.org/blog/sealed-sender/
Signal has a lot less metadata than XMPP.
> Not necessarily true https://signal.org/blog/sealed-sender/
Yeah, no. Timing alone is enough to clearly distinguish a sender, and any attempts like these is pure astronaut engineering to obfuscate something that is trivial to recover by a million side channels.
There is just No. Way. to eliminate the problem of metadata leaks to a centralized server, other than making it practically distributed/P2P. The more time it takes for people to realize this, the worse society becomes.
Yes it does, because the threat model there is not the server itself. You trust that as it's your employer's server and you're using it for work related purposes.
> Timing alone is enough to clearly distinguish a sender
It's a lot harder to pull off than doing an MiTM attack with STARTTLS and then just observing the person's roster being sent to them when they connect lol.
Yes, that is the point. Or it is my home server sitting at my router serving my family. I have been arguing that if I can trust the server then the discussion about E2EE becomes less relevant.
> It's a lot harder to pull off than doing an MiTM attack with STARTTLS and then just observing the person's roster being sent to them when they connect lol.
And here you make the dangerous mistake that I most hate. It's not only trivially easy for the server operator to leak metadata, it's actually HARD to avoid it.
That works in your situation, but not for most people who don't want to have to maintain a moving part. Also hosting in general on a residential connection can depend on the provider and even availability of good internet.
For a lot of people it wouldn't even be possible if they wanted to and that's not getting into the technical investment they would have to make in knowing how to do such a thing in the first place.
> And here you make the dangerous mistake that I most hate. It's not only trivially easy for the server operator to leak metadata, it's actually HARD to avoid it.
It's a lot easier than simply not having that data server side in the first place like Signal for example.
Frankly, that works for the majority of XMPP users -- let's not forget about that. But yes, this is a problem today for many consumers. However, I see this as a much better direction for the Internet as a whole to take -- see efforts such as ownCloud and the like -- , rather than just conceding defeat and accepting a centralized Internet, or worse: the extremely dangerous idea that centralization increases security. Which should only be seen as the non-sense it is.
> It's a lot easier than simply not having that data server side in the first place like Signal for example.
You still do not get the point here at all. This is not about storage. This is not about the server implementation. As long as there is a communication at all between me and the server and then my contacts and the server, it is irrelevant if you are storing the roster or not. ANYONE (*anyone with access to that server) can easily pick it up. In fact, it is HARD not to leak it up, even by accident. Barring a P2P Freenet-like thing, this is _unavoidable_. (and even with P2P/Freenet/Onion/whatever it's not trivial) And due to the nature of IMs, metadata is practically as big an issue than protecting the payload itself.
I think you can still have decentralization without having to be a sysop. That may be server operators that run small servers etc.
Decentralization doesn't inherently mean privacy though and it's important to remember that.
> You still do not get the point here at all. This is not about storage
Pretty sure signal servers can't intercept messages or decrypt them. In regard to the client you cannot send unencrypted messages. We do know that lawful interception warrants sent to Signal are not particularly effective only registration time and last connection time is available. https://signal.org/bigbrother/
Please, I'm really trying to put the emphasis on metadata, and definitely Signal servers can intercept that at will. Even here on HN there was recently an article of how "lawful interception warrants" were targeting Apple's and Google's _push notification servers_ (those _by design_ really only have access to metadata -- that should speak about how important metadata is for law enforcement). The Signal server has access to significantly more metadata about you and your communications than your typical push server. Again, there's just no contest here: simply avoiding the issue of using their server in the first place is much better than anything they claim* to do (or even better than anything they could _physically_ do).
* I absolutely detest these type of "our privacy is great, believe us!" pages. Time and time again it shown that they are absolutely useless. Where did Apple report that their push notification servers were tapped? The fact that a server collects enough data about you that it is a tempting target for authorities should be cause for concern, not relief.
This never effected signal as no data that is sensitive was ever sent via that. Again though warrants against Signal are not new, and for years law enforcement has been getting the same answers to their subpoenas. If it was "possible" as you say and that "they do", pretty sure the ACLU would not be making submissions to a court that "this is all that is available <registration date> & <connection date>" especially as the source code is open, it would be easy to verify if that was in fact true.
> I absolutely detest these type of "our privacy is great, believe us!" pages
The page literally has the legal request and reply, these would be able to be checked against court records. Remember being in contempt of a court order is actually punishable, so if there was more I'm sure Signal would have been fined by now lol.
How are you still missing the point that this is _about metadata_? No one is sending "sensitive data" through a push notification in the first place. You have to go out of your way to do that. My point was to show you that the authorities _are_ after metadata.
[1]: https://www.ndss-symposium.org/ndss-paper/improving-signals-...
[2]: https://arxiv.org/abs/2305.09799
[3]: https://github.com/simplex-chat/simplex-chat/issues/4620#iss...
https://github.com/simplex-chat/simplex-chat?tab=readme-ov-f...
but the first 2 points were already implemented as shown in their Roadmap[1], so they are going to probably remove them
[1]: https://github.com/simplex-chat/simplex-chat?tab=readme-ov-f...
The image in question does not contain puking. That's a tongue, not vomit.
https://bunnypa.ws/sticker/CAACAgEAAxUAAWByYjqChwgli1QKv81yw...
Here's another from the same artist: https://bunnypa.ws/sticker/CAACAgEAAxUAAV91eRTulCrBXcKzxCrPY...
It contains a disgusted reaction. The logos in question are visually "muddying the waters", too.
https://notes.valdikss.org.ru/jabber.ru-mitm/
That attack strikes me as generic. As in not anything to do with XMPP specifically.
The fact that STARTTLS is even possible with that protocol is bad.
> https://notes.valdikss.org.ru/jabber.ru-mitm/
With an up to date Conversations on a modern server we have a pretty good chance to detect or prevent that style of attack due to a mechanism called SASL Channel Binding.
Note that the author of the linked article complains about getting the same sort of article in reply. That is also common...
Can you point out where this happens? I didn't come away with this impression at all.
Signal, Matrix, Telegram, XMPP; Use whatever you want. But there is a lot of FUD if not outright lies in that blog post. The author looked at Conversations for all but five minutes, desperately trying to dig up some dirt.
For example...
* The auth tag truncation was 'silently' introduced in the spec. It wasn’t. The author retracted that but only barely
* ominously pointing out that Conversations has a SASL implementation (In fact Conversations can use that to detect some MITM attacks; which is pretty cool)
* ominously pointing out that Conversations has a certificate parser (yes and so does almost everything that uses TLS)
It's trivial to use TLS without writing your own certificate parser. Doing this means taking on a lot of unnecessary risk, such as CVE-2023-33202.
Your encrypted messaging application shouldn't need to have a separate X.509 or ASN.1 parser built into it. If you're going to use them from TLS, you should rely on the library your OS vendor maintains for you, since they have an incentive to keep theirs secure anyway.
"Ominously pointing out" that the Conversations project has taken on an unhealthy amount of complexity and risk isn't FUD, it's a criticism of how the project is managed. Confuse the two at your own peril.