2025-10-16 –, Alan Turing
[matrix] as an end-to-end encrypted communication standard has its flaws. Flaws in privacy, flaws in complexity. With the standard of Messaging Layer Security (MLS), the [matrix] ecosystem has the opportunity to address old flaws, rethink room state and increase interoperability.
In this talk, I will provide a beginner's guide on challenges of [matrix] 3.0.
Messaging Layer Security (RFC 9420, MLS) is a modern layer for end-to-end encrypted group messaging providing Forward Secrecy (PFS) and Post-Compromise Security (PCS). MLS further provides performance that’s logarithmic in the group size, an easy migration to post-quantum security, and is a rigorously analyzed protocol.
This talk will discuss the opportunities and challenges offered by MSC4256 proposing a way to integrate MLS into [matrix] rooms.
As a guidance, I will focus on the following questions :
- Which advantages does MLS feature over Olm ?
- Which tradeoffs can we accept with an interoperable encryption standard ?
- How can we keep a federated ecosystem working with an encryption standard not meant for complete distribution ?
- How can we ensure to keep sync of MLS state and [matrix] room state ?
- How can we store message history and get SSSS to work with MLS ?
- How can we incrementally migrate an ecosystem to another encryption standard ?
The entire topic of MLS is obviously too big for a single talk. Many of the open questions may only be discussed briefly. The aim of this talk is not to present outstanding solutions like a miracle but rather to inform about the current state of the specification, the ecosystem and next steps.
Hello, my name is Braid (she/her) !
I'm working consultant in the Matrix ecosystem, specialized on Encryption, Client development and Healthcare applications.
Before ending up in the Matrix world, I've been working as Software Architect for Cryptography Architecture in healthcare, later on as Matrix Client developer and nowadays as general Matrix Solution Architect.
Apart from work, I'm developer of < polycule > and a couple of other open-source projects. I use AArch64 hardware, fight for digital sovereignty, privacy and libre software everywhere.
I'm member of The Matrix.org Foundation's Events Working Group. You can ask me about railways !