MLS and Matrix don't mix well. But why is that and what can we do about it?

Since I got to touch that area a bit, I'll try to give some answers, but don't expect solutions.

We will be looking how MLS and Matrix work internally, how a tree is a DAG but a DAG not a tree and maybe we will have some glorious idea or get frustrated. No promises!

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/Z9B878/

For decades, government agencies have relied on proprietary, siloed communication systems. Today, several Swedish initiatives are exploring new paths forward.

First, we will provide details on the latest developments within SAFOS, a service designed to establish a potential national standard for secure messaging, video conferencing, and real-time collaboration.

Second, we will share insights from eSam — a voluntary collaboration between public agencies — where a multi-agency task force is evaluating options for a common, open, and federated protocol for real-time communication. We will discuss our evaluation criteria, the challenges, and the potential of solutions such as Matrix to foster true interoperability, decentralization, and robust security for Sweden's public administration.

Join us to learn how Försäkringskassan and eSam are exploring ways to build a future-proof communication infrastructure based on openness and collaboration.

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/DZBGLP/

In this talk, we’ll take you through the real-world journey of developing and approving a TI-Messenger - a secure, interoperable messaging application built on top of the Matrix protocol for use within Germany’s healthcare system. What began as am idea soon grew into a tightly regulated, multi-stakeholder project, with high demands on privacy, trust, and compliance.

This session is less about features and more about transformation. It’s a case study of how we shaped a Matrix-based messenger to meet the strict security, interoperability, and governance requirements defined by the gematik specification, and how that shaped our development process in return. Unlike general-purpose Matrix clients, the TI-Messenger is deeply constrained by legal frameworks, security audits, and standardized certification making the path from concept to approval full of unique challenges.

We’ll reflect on what we learned about applying Matrix in high-trust environments, what we would do differently, and how our experience could inform similar efforts elsewhere. Whether you’re working in the public sector, healthcare, or simply curious how Matrix can scale to more regulated use cases, this talk offers an inside look at what it takes to make Matrix meet mission-critical standards.

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/YMCDE7/

Code review is a central part of everyday developer jobs. The motivation to create this talk was a quote: “The most important superpower of a developer is complaining about everybody else's code.” In this talk, I’ll explain my approach to better code review. Sometimes, it’s hard to convince a colleague about change or don’t change some lines of code. In my talk I would like to cover some best practices from my software engineering experience about efficient and honest code review. How to create a culture of perfect code review. How to apply automatic tools to improve code review routine of repetitive comments or suggestions. How to write/or reuse coding style guides for your team to reduce the time spent arguing about naming conventions and different styles. What needs to be automated and what needs to be not automated during code review? The key role of patterns that can be reusable is not to confuse colleagues.

about this event: https://talks.python-summit.ch/sps25/talk/ESM3K7/

With the TI-Messenger, built on the Matrix protocol, Famedly has enabled secure and interoperable communication across the German healthcare system, from hospitals to pharmacies. Adoption is growing rapidly, with millions of potential users on the horizon.

In this opening talk, we’ll look back at TIM’s journey so far, highlight its impact and adoption, and then take a step beyond healthcare into the government. We’ll also give a glimpse into MLS and how it will strengthen security and interoperability for all Matrix-based applications in the future.

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/XTTQ3R/

Since 2024, the Swiss federal government has been obliged by the new EMOTA law to publish all its software under open source licenses. This new 'Federal Act on the Use of Electronic Means to Conduct Official Tasks' (EMOTA) has had an impact on IT procurement and open source activities in Switzerland. By encouraging the creation of open source communities, the law reduces vendor lock-in and strengthens digital sovereignty.

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/KCKEYJ/

[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 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.

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/BAKSEA/

Sometimes getting an approximate answer is super good enough. How do you check for duplicates, count unique users, or track item popularity when your dataset won’t fit in memory? Enter probabilistic data structures like Bloom filters, Count-Min Sketches, and HyperLogLog! This talk introduces these powerful tools, demonstrates simple implementations in Python, and gives you ideas on when to use them. Walk away ready to apply these techniques in your own projects - no advanced math required.

about this event: https://talks.python-summit.ch/sps25/talk/QBXDUQ/

A welcome message and useful information from the organisers. You will also find useful information on our [website](https://www.python-summit.ch/). Or feel free to ask any member of staff if you have a question.

about this event: https://talks.python-summit.ch/sps25/talk/LL3K3L/

As project lead of Matrix, Matthew gives a snapshot of where the project is at. Highlights should include:

* Overview of recent high-profile Matrix deployments and uptake

* Overview of the recent major projects to fix state resets and improve decentralisation reliability

* Overview of making Matrix a safer place via improved Trust & Safety work

* Progress on Matrix 2.0 MSCs (Next Gen Auth, Sliding Sync, MatrixRTC) and uptake

* Progress on Olm/Megolm improvements (history sharing, TOFU, invisible crypto, etc)

* Progress on Next-generation encryption work

...and more!

Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/

about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/8PEMJB/