[AnyTimeTraveler]

Actually, there are many cons to e2e, especially with bigger groups. I've read a lot about Signal's and Matrix's development and there are many problems that don't exist when sending data over a simple SSL connectiom to a server.

For example: You have a group with 100 Members, do you encrtpy each message you send 99 times for each recipient? Not likely. So you use a send key that everyone else can decrypt.

But then what if the group changes? Does everyone has to replace their send-keys, because the party that left can still decrypt all those messages otherwise.

That means you have to do n-1 key exchanges whenever a party leaves or joins. Otherwise it wouldn't be secure anymore.

There are some clever ideas about key exchanges, but so far the messengers that implement them are not widely used and since there is no profit in it, no one is in a hurry to compete.

[bsaul]

From what i’ve read, whatsapp is doing just what youdescribed for group chat, and it’s working fine... now maybe you’re talking about groups with hundreds of people ?

[afiori]

telegram groups allow for thousands of users.