They might be able to relay them in a way that the end to end encryption is actually handled on the phone and the relay only relays encrypted messages.
That would likely still give them a capability to MitM but it’s plausible that they couldn’t passively intercept the messages.
You give them the credentials for your Apple account. The security concept is “trust me bro” and that’s really the best they can do unless Apple helps them (which they have no reason to)
“Trust me bro” is always the security concept of any service where you don’t control the client - that includes regular iMessage (you have to trust Apple) and Google’s RCS (you have to trust Google). They can always instruct or update the client apps on people’s phones to start doing something they weren’t previously doing.
That being said, I would not trust some random sketchy company with something so important. Even if you trust their intentions, you cannot trust their competence in preventing breaches. Stuff gets hacked and leaked all the time.
Absolutely. The iMessage network isn’t some unknowable beast, it “just” requires an Apple device be involved and activated to work. In order to spoof that far, you’d essentially need to emulate quite a bit on device.
They might be able to relay them in a way that the end to end encryption is actually handled on the phone and the relay only relays encrypted messages.
They’d need to control the app on both phones in order to control what it’s encrypting/decrypting. Their system only works because they’ve got a device in the middle separately decrypting/re-encrypting each message. Google’s Messages app can’t read iMessages; Apple’s Messages app can’t read Google’s proprietary encrypted RCS messages.
Of course if you want universally cross-platform messaging, complete with full-resolution photos and available with end-to-end encryption, there’s this crazy new technology called “email.” I feel like there’s a missed opportunity for making setting up S/MIME easier.
