Thanks - I remember reading about the issues Tor had operating in China and the sophistication of the government's deep packet inspection. I think TLS is not secure in China, I think I read that the government controls the CAs and MiTMs all traffic.
TLS isn’t everything, you might not trust the server operator. In fact you probably shouldn’t if you’re sending a PM.
This is asking about P2P Matrix, where typically there isn’t a server involved. The transport layer security runs between the peers, effectively providing a form of end to end encryption if there are no nodes in the middle.
> Doesn't this still matter if the internet traffic itself is tapped? If I'm understanding this correctly we'll still want E2E for things like deep packet inspection in China (or bulk collection by western governments).
If TLS has been compromised between your nodes, then yes - E2EE would give another level of protection; security in depth. I guess it depends on whether you believe your government has the ability to compromise transport layer security between arbitrary peers on the network.
For pure P2P Matrix, there might be some compromise where one uses the E2E keys and key verification to secure the transport layer security (thus giving you E2EE if there is no server in between, but without all the complexity of a cryptographic ratchet). This might give you best of both worlds - but the second you start accumulating data on a server somewhere you'd be back wanting proper E2EE.