Google has made an official announcement regarding its commitment to enable interoperable end-to-end encrypted (E2E) communication among major messaging platforms. As part of this effort, Google intends to integrate the Message Layer Security (MLS) protocol into both Google Messages and the Android operating system.
The company expresses strong support for regulatory initiatives that mandate interoperability for large E2E messaging platforms, seemingly referring to the European Union’s Digital Markets Act. This regulation would necessitate iMessage’s compatibility with other messaging services.
Google emphasizes the importance of adopting open and industry-vetted standards, especially concerning privacy, security, and end-to-end encryption. Without such standards, implementing advanced features like end-to-end encrypted group messaging becomes impractical, requiring multiple encryptions and deliveries for different protocols.
A lack of standardized practices could result in a disorganized assortment of makeshift solutions, potentially compromising security standards to accommodate the least secure system and increasing costs for smaller providers.
To achieve interoperable E2E encrypted messaging, Google highlights the Internet Engineering Task Force’s (IETF) Message Layer Security (MLS) specification RFC 9420, which includes an efficient asynchronous group key establishment protocol with forward secrecy (FS) and post-compromise security (PCS) for groups ranging from two to thousands of users.
Implementing MLS would allow practical interoperability across various services and platforms, facilitating communication among thousands of multi-device users. This advancement opens up numerous opportunities for users and developers of interoperable messaging services.
Moreover, MLS offers the necessary flexibility to address emerging threats to user privacy and security, such as quantum computing.
Google’s plan includes integrating MLS into its existing Messages app, which currently supports E2E encrypted 1:1 and group Rich Communication Services (RCS) chats. Additionally, Google intends to support the widespread adoption of MLS throughout the industry by open-sourcing their implementation in the Android codebase. The specifics of how RCS will factor into this initiative have yet to be disclosed.