GSMA Introduces End-to-End Encryption for Cross-Platform RCS Messaging

The GSM Association (GSMA) has announced a major upgrade to the Rich Communication Services (RCS) standard, introducing end-to-end encryption (E2EE) using the Messaging Layer Security (MLS) protocol.

This enhancement marks the first large-scale messaging system to offer interoperable encryption between different client implementations, ensuring a higher level of security for users across platforms, including Android and iOS.

Encrypted RCS everywhere

The updated RCS specifications were developed through collaboration between mobile operators, device manufacturers, and technology providers, including Apple and Google. GSMA's Technical Director, Tom Van Pelt, highlighted that the new standards define how MLS can be applied within RCS to protect messages and media as they travel between devices.

Work on enabling E2EE for cross-platform RCS messaging began in September 2024, with GSMA leading the effort to establish encryption that would prevent third parties — including messaging providers and carriers — from accessing message content. Apple, which introduced RCS support in iOS 18 last year, confirmed its involvement in the process, with spokesperson Shane Bauer stating:

“End-to-end encryption is a powerful privacy and security technology that iMessage has supported since the beginning, and now we are pleased to have helped lead a cross-industry effort to bring end-to-end encryption to the RCS Universal Profile published by the GSMA.”

Google, which has long supported E2EE in RCS messages exchanged within its Google Messages app, also welcomed the update. Ed Fernandez, a Google spokesperson, emphasized the company’s commitment to secure messaging and its plans to implement the new standard as quickly as possible.

Impact of RCS Universal Profile 3.0

The new encryption feature is part of the RCS Universal Profile 3.0 release, which introduces several improvements beyond E2EE. Key enhancements include:

• A richer deep-link format for engaging with businesses over RCS.
• Improved audio messaging codecs for better voice quality.
• Easier management of business messaging subscriptions.
• Continued support for features like group messaging, high-resolution media sharing, read receipts, and typing indicators across iOS and Android.

RCS has long been positioned as the successor to SMS, offering modern messaging features comparable to proprietary services like iMessage and WhatsApp. However, a lack of encryption for cross-platform messages was a significant security gap — one that this update aims to close.

What’s next?

Apple confirmed that support for end-to-end encrypted RCS messages will be rolled out to iOS, iPadOS, macOS, and watchOS in future updates. Meanwhile, Google and other mobile ecosystem players are expected to work swiftly on integrating the new standard.

For users, this development means that private and secure messaging will no longer be restricted to closed ecosystems like iMessage or WhatsApp. As more providers implement MLS-based encryption in their RCS clients, users across different platforms will benefit from a more secure and privacy-focused messaging experience.