The GSM Association (GSMA) has officially announced its support for end-to-end encryption (E2EE) to secure messages sent via the Rich Communications Services (RCS) protocol. This move brings much-needed security protections to cross-platform messages shared between Android and iOS platforms.
In line with this, the GSMA has released new specifications for RCS that include E2EE based on the Messaging Layer Security (MLS) protocol. This is achieved through the RCS Universal Profile 3.0.
According to Tom Van Pelt, technical director of GSMA, “The new specifications define how to apply MLS within the context of RCS. These procedures ensure that messages and other content, such as files, remain confidential and secure as they travel between clients.”
This development means that RCS will be the first large-scale messaging service to support interoperable E2EE between different client implementations from different providers in the near future.
It’s worth noting that Google’s own implementation of RCS, used in the Messages app for Android, already secures conversations using the Signal protocol to address the lack of built-in E2EE protections. However, the encryption safeguards are currently limited to messages exchanged via the app and do not apply to messages exchanged with iOS Messages users or users of other RCS clients on Android.
The GSMA’s announcement comes nearly six months after the organization revealed its plans to implement end-to-end encryption to secure messages sent between the Android and iOS ecosystems. This move followed Apple’s decision to roll out support for RCS in its own Messages app with iOS 18.
In July 2023, Google announced its intention to add support for MLS to its Messages service and open-source implementation of the specification.
Van Pelt emphasized that “RCS continues to support a range of interoperable messaging functions between iOS and Android users, such as group messaging, the ability to share high-resolution media, and see read receipts and typing indicators.”
Google commented, “We’ve always been committed to providing a secure messaging experience, and Google Messages users have had end-to-end encrypted (E2EE) RCS messaging for years. We’re excited to have this updated specification from GSMA and work as quickly as possible with the mobile ecosystem to implement and extend this important user protection to cross-platform RCS messaging.”
