I’m not sure if it is entirely accurate to compare them in this way, as “Matrix” refers to simply the protocol, whereas “Signal” could refer to the applications, server, and protocol. That being said, is there any fundamental difference in how the Matrix ecosystem of federated servers, and independently developed applications compares to that of Signal that would make it less secure, overall, to use?
The most obvious security vulnerability that I can think of is that the person you are communicating with (or, conceivably, oneself, as well) is using an insecure/compromised application that may be leaking information. I would assume that the underlying encryption of the data is rather trustworthy, and the added censorship resistance of federating the servers is a big plus. However, I do wonder if there are any issues with extra metadata generation, or usage tracking that could be seen as an opsec vulnerability for an individual. Signal, somewhat famously, when subpoenaed to hand over data, can only hand over the date that the account was created, and the last time it was used. What would happen if the authorities go after a Matrix user? What information about that user would they be able to gather?
Signal goes very far to protect even the tiniest bits of metadata.
For example see sealed sender, private contact discovery and group v2.
On the other hand, matrix stores your profile info, group membership, and ongoing conversation metadata in plaintext, some of them replicated across homeservers. In addition to metadata that matrix doesn’t encrypt, they also do not encrypt some actual data like emoji reactions.
Edit: clarified that conversations are not in plaintext. My wording what confusing as hell sorry.
Matrix doesn’t store your ongoing conversation in plaintext. It’s encrypted by default.
What I meant by that is not the actual message content, but who you’re talking to and when is stored on the home server.
As I am not exactly sure what you are referring to.
I’m assuming that this statement is referring to what was said here:
This one is incorrect, wording was confusing as hell.
Profile picture and usernames are public, no way to make them private in anyway.
Your home server and the home servers of every other member of the group can tell exactly who is part of the group
I actually meant who and when you send message to and receive messages from.
Matrix doesn’t have profiles. It has usernames, and it has avatars if you choose to upload one.
I believe this was true when I last checked. They plan to fix it.
That’s just plain false. Please stop spreading misinformation.
That’s what I call a “profile”.
Call me when it’s fixed.
Yeah my wording was incorrect, see edit.