They are also the only RCS supplier on Android. A random messaging app can’t simply add RCS messaging functionality.
You are correct that an app can’t directly implement RCS but it can support it. RCS is implemented by the carrier, not by Google or any other text application.
RCS is an open standard that any carrier can implement to replace SMS/MMS. The only thing special that Google does is on top of RCS is provides E2E via its own servers for handling messaging. The E2E isn’t a part of RCS, though it should be IMO. Regardless, Google doesn’t ‘own’ the Android implementation because it isn’t a part of Android, other than it can support the carrier’s implementation of RCS.
If you didn’t create private and exchange public keys with the other party, you aren’t fully in control. I’m not saying that as some kind of righteous purist, just a technical point of note.
You are correct that an app can’t directly implement RCS but it can support it. RCS is implemented by the carrier, not by Google or any other text application.
RCS is an open standard that any carrier can implement to replace SMS/MMS. The only thing special that Google does is on top of RCS is provides E2E via its own servers for handling messaging. The E2E isn’t a part of RCS, though it should be IMO. Regardless, Google doesn’t ‘own’ the Android implementation because it isn’t a part of Android, other than it can support the carrier’s implementation of RCS.
No app on Android can use RCS yet, other than Google messages.
E2EE via server sounds wrong.
If you didn’t create private and exchange public keys with the other party, you aren’t fully in control. I’m not saying that as some kind of righteous purist, just a technical point of note.