iPhone and Android users will soon have the ability to send encrypted RCS messages to each other.

Text messages sent between iPhones and Android devices will soon benefit from end-to-end encryption (E2EE), after the GSM Association (GSMA) yesterday published new specifications for the Rich Communication Services (RCS) protocol that include support for cross-platform E2EE.

RCS is a long-standing effort to enable SMS-style cross-platform communications with richer features, such as group messaging, typing indicators, read receipts, and file-sharing — similar to what messaging apps such as WhatsApp provide. While many Android handset makers had adopted RCS through the years, Apple was the main outlier until it finally succumbed with the introduction of iOS 18 last year. Most of the core RCS features have been available for cross-platform messaging since then, but E2EE has hitherto been missing — until now.

Selling point

E2EE, for the uninitiated, is a data encryption method that ensures only the sender and the recipient of a message can read its content. For tech companies, this privacy-preserving promise is a major selling point, as it assures users that their messages are safe from snooping. Apple has offered E2EE since it launched iMessage back in 2011, though of course that only worked between iOS devices, while WhatsApp completed its E2EE rollout in 2016 (and, again, it only worked between WhatsApp users). Google, for its part, has previously added E2EE to its own Messages app, but this was its own proprietary undertaking separate to the RCS protocol itself.

Encrypting messages across not only different clients but also entirely different platforms comes with its own unique challenges, which is where the GSMA’s universal profile enters the fray, providing a standardized specification for consistent, interoperable RCS messaging across devices, networks, and operators. Based on the cryptographic Messaging Layer Security (MLS) protocol, the new E2EE mechanism in the RCS Universal Profile 3.0 is a vital piece of the interoperable jigsaw, one that will ultimately enable iPhone and Android users to communicate securely via their device’s native messaging app.

“That means that RCS will be the first large-scale messaging service to support interoperable E2EE between client implementations from different providers,” GSMA technical director Tom Van Pelt said in a statement. “Together with other unique security features such as SIM-based authentication, E2EE will provide RCS users with the highest level of privacy and security for stronger protection from scams, fraud and other security and privacy threats.”