The hard part is how do you manage a list of trusted devices.
The thing which is really sad is that there are no end to end encrypted group chats.
The thing which is really sad is that there are no end to end encrypted group chats.
e2e is in beta still, but they have key list management/verification in place already.
In iMessage specifically, or in general? WhatsApp/Signal do use E2E-crypto for group chats.