IIRC Signal just has each group member send each group message to each recipient with the standard pair-wise encryption keys. It's the message's headers that lets the recipient know it's intended for the group and not the 1:1 group.
Additionally the key is regularly updated to provide some degree of perfect forward secrecy and avoid encrypting for people who left the group chat
I think it has senders encrypt messages with each room member's public key, rather than a single shared key. (At least, that's what the behavior I've seen suggests to me.)
Here's the spec, in case you want to comb through it:
https://spec.matrix.org/v1.11/client-server-api/#end-to-end-...
You ask the authors how they solved the problem of server needing to know to which client connection an incoming ciphertext needs to be forwarded, and they'll run to the hills.
They're lying by omission about their security, and misleading about what constitutes as a permanent identifier.
You understand the design quite well, from our past conversations, you simply don't like the fact that we don't recognise user IP address as a permanent user identifier on the protocol level. It is indeed a transport identifier, not a protocol-level identifier that all other messaging networks have for the users (in addition to transport identifiers).
Message routing protocol has anonymous pairwise identifiers for the connections between users (graph edges), but it has no user identifiers - messaging servers have no concept of a user, and no user accounts.
Also, recently we added a second step in message routing that protects both user IP addresses and transport sessions: https://simplex.chat/blog/20240604-simplex-chat-v5.8-private...
In general, if you want to meaningfully engage in the design criticism, I would be happy too, and it will help, but simply spitting out hate online because you don't like something or somebody, is not a constructive approach – you undermine your own reputation and you also mislead people.
> You ask the authors how they solved the problem of server needing to know to which client connection an incoming ciphertext needs to be forwarded, and they'll run to the hills
This is very precisely documented, and this design was recently audited by Trail of Bits (in July 2024), we are about to publish their report. So either you didn't understand, or your are lying.
> They're lying by omission about their security, and misleading about what constitutes as a permanent identifier.
You would have to substantiate this claim, as otherwise it is slander. We are not lying about anything, by omission or otherwise. You, on another hand, are lying here.
That you are spiteful for some reason is not a good enough reason.
Factually, at this point SimpleX Chat is one of the most private and secure messengers, see the comparisons of e2e encryption properties in SimpleX Chat and other messengers: https://simplex.chat/blog/20240314-simplex-chat-v5-6-quantum...
