Post #4827367 · Elektrine

2026-09-17 01:25 UTC

E2EE with large groups is a hassle because you have to do messy key changing protocols every time somene leaves the chat (since you want to invalidate their keys when they leave). If you don’t mind the server (self hosted) seeing the plaintext that’s a lot simpler. Tbh I’ve simply used nextcloud chat or irc for stuff like this. I can’t really recommend nextcloud for various reasons but it was easy for me to set up a chat when I wanted one, since I already had a nextcloud server. Matrix is supposed to be the post-IRC IRC so I’d check into it, but I haven’t used it so far. I’m of the impression that Matrix isn’t E2EE (the server can see the private stuff) but maybe I’m wrong. I think Signal tries to be E2EE but has other problems, including that MLS (the E2EE mechanism) inherently requires a client app instead of being usable with just a browser.

Replies (1)

@litchralee@sh.itjust.works 2026-09-17 03:45

I think Signal tries to be E2EE but has other problems, including that MLS (the E2EE mechanism) inherently requires a client app instead of being usable with just a browser. I’m having trouble imagining what in Signal’s implementation of the Double Ratchet, or any part of RFC9420 Message Layer Security, would inherently require a client app. Perhaps you mean that there is no readily available browser-implemented API for carefully managing secrets? Even in that situation, all the libraries needed to implement the RFC can be compiled as WebAssembly or to JavaScript (with the assumption that the browser and OS are outside a malicious actor’s capabilities) and ran that way. To be clear, I’m not suggesting Signal is perfect, and papers about problems found in Signal and other apps are readily found, like this one from last month. But with that said, it does appear that OP’s described use-case involving hundreds of users in group chats is very much not what Signal was designed for,.

Open ##4827366