Apple confirmed iOS 18 will support RCS messaging on iPhone and then brought RCS functionality to the first iOS 18 betas. You can text your Android contacts via RCS right now, assuming your carrier supports it.
However, Apple said that the iPhone will support the GSMA’s RCS standard, not Google’s implementation. Therefore, RCS on iPhone will lack the end-to-end encryption that iMessage gets, even though Google built encryption into its RCS system. It was clear back then that end-to-end encryption would not come to RCS on iPhone until the GSMA updated its RCS standard.
Fast-forward to late July, and a Google Messages leak reveals that encryption might be in the works for the RCS universal profile, which the GSMA supports. If that’s the case, RCS on the iPhone might also support end-to-end encryption in the near future.
According to Android Authority, the Google Messages app on a Samsung phone contains the following line of text: “+g.gsma.rcs.mls.mls-version.”
That reads like gibberish to most people, though you can make out the GSMA and RCS acronyms. That should tell you that whatever RCS features Google is working on might be in partnership with the GSMA, which oversees the RCS standard.
Where’s end-to-end encryption in all of this? That would be the MLS mention, which is short for the Messaging Layer Security (MLS) standard. The Internet Engineering Task Force (IETF) developed MLS to solve the encryption problem for group chats.
The same blog found evidence earlier this month that Google is adding MLS support to the Messages app in some capacity.
In addition to adding end-to-end encryption to group chats, MLS supports secure chats across apps and platforms. In theory, this could bring encrypted chat communication across chat apps. It’s bigger than secure RCS on iPhone. Other encrypted apps like Signal and WhatsApp could integrate MLS and one day work with Google Messages and other apps.
However, at the time of that MLS discovery, there was no evidence that Google was going at it alone or whether it was working on the RCS Universal Profile. The GSMA mention in that newly discovered line of code indicates that Google might be working on end-to-end encryption for the RCS standard profile, not just its implementation.
As a reminder, Google RCS already supports end-to-end encryption in one-to-one chats and group conversations. But that’s Google’s own implementation, something Apple won’t support on iPhone.
The latest code discovery suggests that other parties could be working on end-to-end encryption for the RCS Universal Profile. The list could include Apple. The iPhone maker might not be fond of supporting RCS on iPhones, but it has to do it. Carrier regulation in China demands it, and pressure from other regulators might have always forced Apple’s hand to adopt it.
That’s to say, we have no idea when end-to-end encryption will be coming to RCS on iPhone. It surely isn’t a priority similar to the other work Apple is doing on iMessage.
However, Apple is all about privacy and security, and the lack of encryption in RCS is something that Apple would have to fix sooner rather than later. Well, Apple would be fixing it by working with Google, the GSMA, and other parties interested in encrypting RCS messages.
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