The British version of the NSA—called Government Communications Headquarters (GCHQ)—wants Apple to secretly add the agency to iMessage chats and FaceTime calls (via ACLU).
It sounds like the agency was enamored of the Group FaceTime bug which let people spy on conversations under certain circumstances. Under the Ghost Proposal the government should be able to add secret chat participants:
It’s relatively easy for a service provider to silently add a law enforcement participant to a group chat or call. The service provider usually controls the identity system and so really decides who’s who and which devices are involved — they’re usually involved in introducing the parties to a chat or call…. In a solution like this, we’re normally talking about suppressing a notification on a target’s device… and possibly those they communicate with.
This is a sneaky way to bypass end-to-end encrypted messaging apps. Conversations will still be encrypted but governments will be able to spy on you anyway. Which essentially renders the encryption worthless if you can’t trust who you’re chatting to.
As the ACLU points out, this won’t be limited to democratic governments. Authoritarian governments will also want to participate. It’s the same backdoor argument all over again: You can’t ensure that only the good guys can use them.