I know RCS is open (as far as the GSMA is open, you probably need to buy a bunch of patents to use the app in places like the USA), but I’m specifically wondering about the encrypted part that Google added on top. Google just sends blobs of encrypted base64 over standard RCS, message encryption is not part of the RCS spec itself as far as I know.
According to papers like these Google seems to be using a mix of Signal’s protocol and, I believe, MLS in group chats since some time this year, but I don’t think they’ve documented their exact format specification or API servers anywhere.
Does anyone know if Google has open sourced/documented their protocol somewhere so other apps can interoperate with them?
I don’t think so, https://reddit.com/r/Android/s/dbT0PE4eft has a response on whether or not it is open source
I know RCS is open (as far as the GSMA is open, you probably need to buy a bunch of patents to use the app in places like the USA), but I’m specifically wondering about the encrypted part that Google added on top. Google just sends blobs of encrypted base64 over standard RCS, message encryption is not part of the RCS spec itself as far as I know.
According to papers like these Google seems to be using a mix of Signal’s protocol and, I believe, MLS in group chats since some time this year, but I don’t think they’ve documented their exact format specification or API servers anywhere.
That is my understanding, is it’s encryption on top of RCS. So even if another messaging system were to use RCS you wouldn’t be able to read them.
They have not and likely will not.