Pay special attention to the Universal Profile. That’s the core spec everyone agreed on a few years ago, the one used for basic texting.
You know what isn’t in there? Encryption. Google will need to either disable encryption in chats with Apple users, or Apple users won’t be able to join encrypted groups.
Is this better than using SMS? Obviously yes. Is this going to fix the iMessage problem? Only if you don’t care about privacy.
I personally don’t ever chat via SMS or RCS so I don’t really care either way, but unless Google opens up and documents its encryption, the user experience will still degrade when talking to iOS people.
It’s been three months and there is no documentation about what messages use Signal, what messages use MLS, the specifics of the encoding (I’m guessing the base64 blob is just raw Signal/MLS, but who knows?), and I can’t find much information about Google’s key servers.
They’ve documented the encryption primitives they use for Signal-style messaging, but that documentation uses phrases like “The RCS file transfer XML is extended to include this encrypted payload”. Extended in what way? Where’s the schema? Are they using the same mechanisms in MLS?
They haven’t closed off their implementation like iMessage has, but they also haven’t done much to allow external integration. Building a compatible client will still involve reverse engineering the Google Messages app with packet traces/eBPF captures and interpreting the XML and their binary schemas (and hopefully not get the details wrong).
Meanwhile, Apple has promised to support the Universal Profile. We have no promises of E2EE support at the moment. Even if Apple could easily get the necessary documentation from Google, who’s to say they will? If they don’t, they can label any group text “insecure” when RCS gets involved, which should help push people back into Apple’s walled garden.
Pay special attention to the Universal Profile. That’s the core spec everyone agreed on a few years ago, the one used for basic texting.
You know what isn’t in there? Encryption. Google will need to either disable encryption in chats with Apple users, or Apple users won’t be able to join encrypted groups.
Is this better than using SMS? Obviously yes. Is this going to fix the iMessage problem? Only if you don’t care about privacy.
I personally don’t ever chat via SMS or RCS so I don’t really care either way, but unless Google opens up and documents its encryption, the user experience will still degrade when talking to iOS people.
Google uses the Signal protocol for encryption and they do intend to allow for interoperability:
https://9to5google.com/2023/07/19/google-messages-mls-encrypted/
This is not something Google was ever against doing
It’s been three months and there is no documentation about what messages use Signal, what messages use MLS, the specifics of the encoding (I’m guessing the base64 blob is just raw Signal/MLS, but who knows?), and I can’t find much information about Google’s key servers.
They’ve documented the encryption primitives they use for Signal-style messaging, but that documentation uses phrases like “The RCS file transfer XML is extended to include this encrypted payload”. Extended in what way? Where’s the schema? Are they using the same mechanisms in MLS?
They haven’t closed off their implementation like iMessage has, but they also haven’t done much to allow external integration. Building a compatible client will still involve reverse engineering the Google Messages app with packet traces/eBPF captures and interpreting the XML and their binary schemas (and hopefully not get the details wrong).
Meanwhile, Apple has promised to support the Universal Profile. We have no promises of E2EE support at the moment. Even if Apple could easily get the necessary documentation from Google, who’s to say they will? If they don’t, they can label any group text “insecure” when RCS gets involved, which should help push people back into Apple’s walled garden.