Matrix Metadata Problem: the server sees everything except your messages

a month ago by verifytheposter to c/matrix

Matrix Metadata Problem: the server sees everything except your messages

People pick Matrix because of end-to-end encryption. But E2EE only protects message content — everything around it is plaintext.

The server sees:

Your ID, IP, client type and version, device you use
Your presence, typing status, read receipts
Which rooms you join and when you join/leave
Who else is in those rooms → your entire social graph
Room names, topics, avatars (all plaintext state)
For every message: who sent it, which room, a millisecond timestamp, type, size

And federation copies most of that to every other server whose users are in the room. Your "social footprint" isn't one copy — it's as many as there are servers.

stratself 3 points a month ago

Federation never sees your client IP and device details. The same problem applies to most messaging services and protocol anyways. Do you have any better offerings?

Although that SynExtract tool in the linked paper could be nice.

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verifytheposter 0 points a month ago

Signal is free from this disaster, and client version and device details are only visible to the main server — not to mention the avatar, name, and many more items listed above being in plain text.

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stratself 5 points a month ago

Kindly find me proof that the Matrix protocol explicitly sends a user client's version and device details towards another server when engaging in federation.

Do note that Matrix and open protocols are federated, and requires some amount metadata to actually process+route stuff.

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verifytheposter 0 points a month ago

It's already a problem that it sends the client's version, device details, avatar, and bio at all. Those device details are transmitted during federation along with everything else.

https://spec.matrix.org/latest/server-server-api

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stratself 1 point a month ago

Again in the linked Server-Server API, I can only find mentions of device details here. The most that is required is an opaque device ID, which alone cannot infer more device details. device_display_name is fully optional and hasn't been sent by servers for ages.

These device updates are used for sending device keys, which is needed for establishing multi-device E2EE sessions. The same kind of ratchet-based E2EE that Signal utilizes. The paper you linked only investigated a single server, non-federated deployment, extrapolating every finding to federation just doesn't make any sense.

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fruitycoder 2 points a month ago

I wonder if there is a more practical solution of having matrix servers just be encrypted message routers. Maybe even encrypt the specific users address by the home server and then have federated servers just build routing tables for each other.

So my client sends an unencrypted header saying "send this to server A" with the specific user address being encrypted with Server A's public cert, the message content stays encrypted by the users pub cert. The message gets routed over to there distant server, user address decrypted on server, content decrypted on client.

Have server data like rooms, typing status, etc just be private messages ment for users sent by the distant server it's self. Home server only sees the rooms it's managing then.

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JoeBidet 2 points a month ago

Matrix shall be considered a "metadata-rich protocol" :(

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dropdrip 1 point a month ago

Matrix was always a terrible protocol made by Zionists to embed themselves into government and corporate channels whilst posturing itself as 'secure' and independent (self-hosted). Critics said over and over: it's shit. Now those duped are getting defensive. Good ploy mossad. Overall it's been very effective.

This isn't support for Signal either. It's shit too.

The problem is users. Always has been.

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geneva_convenience 1 point a month ago

Not just made by Zionists, made by notorious Israeli spyware company Amdocs.

And after moving to the UK the devs deny that Amdocs was a spyware company despite it having multiple massive spying scandals such as wiretapping White House phones https://en.globes.co.il/en/article-384876

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