Reminder: the E2E encryption in WhatsApp and iMessage is backdoored, and cannot be trusted:
@ilumium if the device running imessage escrows the e2e keys to the same org as runs the imessage relay servers, using keys that are known to that org (i.e. icloud backup is not e2e, and backs up the imessage keys), then that's an e2e backdoor.
in an actual e2e system, you can't get message content without getting the endpoint keys from the endpoints. apple escrows the keys to icloud.
@sneak and @ilumium, I believe it’s also possible to have client-side back doors. That’s just an alternative theory, I don’t know what actually happens.