Element X Web (matrix-conf-2025)

Element X is coming to web and desktop! What does that mean? We’re going to make the apps simple, familiar, reliable and fast! Come learn more about the vision we have put together and all the progress we have made so far! The talk will cover: * The qualities/goals we are aiming for in EWX * The high level plan to achieve this including: * Our product and design strategy * The phased plan for delivery * The key technologies that will enable the transformation * An update on progress and next steps Licensed to...

Why do I have 2 passwords? How to talk about encryption in Matrix (matrix-conf-2025)

Most modern software applications give total trust to the service provider. End-to-end encrypted (E2EE) services are different: the service provider is a gateway, and the real trust is with other people. This is unfamiliar, and can make using E2EE confusing. When you add in federation (meaning lots of different service providers) and a diverse set of client apps, trying to make Matrix's encryption understandable is tricky. It would help to have a shared set of words and definitions. In this talk I describe MSC4161, which attempts to establish a shared vocabulary, and then my own thoughts...

Joining the conversation: balancing privacy with usability for encrypted messages (matrix-conf-2025)

Being able to read the conversation in a room before you joined is a critical feature for some usecases, but end-to-end encryption makes it tricky to implement. In this technically-focussed talk, we'll cover the challenges behind implementing "history sharing", why previous attempts in this area failed, and how we solved those problems with minimal impact on the security or efficiency of the protocol. The Element Crypto team have been working on [MSC4268](https://github.com/matrix-org/matrix-spec-proposals/pull/4268), aka "Sharing room keys for past messages". We'll talk about why this is difficult from the cryptographic perspective, and discuss the architecture behind the...

39C3 Presale: Modus Operandi

Wir freuen uns, euch den Vorverkauf für den diesjährigen Chaos Communication Congress anzukündigen. Der Vorverkauf wird dieses Jahr ziemlich genau ablaufen wie letztes Jahr:

Der Vorverkauf wird wieder das System replizierender Voucher einsetzen. Dabei gibt es wieder zwei Phasen, die Voucher-Phase und den offenen Verkauf. Wir erklären das hier mal „kurz“. Wenn ihr weitere Details wollt, haben wir auch eine Erklärseite, die wir über die nächsten Tage weiter befüllen.

Die Voucherphase vom 21.10.2025 bis höchstens zum 12.11.2025 läuft so:

The High Price of Open Source: Building a Business Around Matrix (matrix-conf-2025)

Open Source has never been easy, but doing Open Source in the Matrix ecosystem poses a unique set of challenges. Add the pressure of sustaining a company on top of that, and you quickly find yourself in uncharted, and often uncomfortable, territory. This talk reflects on the reality of maintaining open source projects in the Matrix universe, especially from the perspective of a business. It dives into the tension between openness and exploitation, when others take your work without contributing anything in return, undermining sustainability and motivation. Through real-world experiences and hard-learned lessons, this session...

Trialing Matrix within the European Commission for resilient and sovereign communications (matrix-conf-2025)

Looking for more resilience and sovereignty, the European Commission has been running a trial Matrix deployment. This talk will present some of the work done. 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/MDHBPY/
Video:matrix-conf-2025-81512-eng-Trialing_Matrix_within_the_European_Commission_for_resilient_and_sovereign_communications_hd.mp4

Using Python's array API standard for ESA's Euclid mission (sps25)

Over the years, the lack of an array data type in Python has resulted in the creation of numerous array libraries, each specializing in unique niches but still having some interoperability between each other. NumPy has become the de facto array library of Python, and the other array libraries try to keep their API close to that of NumPy. However, this often becomes infeasible, and the libraries deviate out of necessity. To make Python's array libraries shake hands with each other without any inconsistencies, the Consortium for Python Data API Standards has formalised an...

Bytecode and .pyc files (sps25)

Bytecode, the internal language of instructions used by the interpreter is something that perhaps most Python developers have heard about, but few have dug into. This talk will try to explain the idea behind bytecode and how it works. We will see how to extract bytecode from functions - with `dis` module, and from `.pyc` files (and what is the idea of `__pycache__` directories). Then, the other way around: we’ll check the possibility of building new functions with raw bytes in runtime. about this event: https://talks.python-summit.ch/sps25/talk/9NWPB9/
Video:import-56444-eng-Bytecode_and_pyc_files_hd.mp4

Why you, as a Python developer, should learn Rust (sps25)

Why should you, as a Python developer, learn Rust? In this talk, we will explore Rust's compelling answers to this question. Rust offers guaranteed type safety and memory safety without a garbage collector, "fearless concurrency", and incredible performance. We will look into some of Rust's most distinctive features from a Python perspective, including its strict compiler, the ownership and borrowing system, null safety via `Option`, and explicit mutability. We will discover how Rust eliminates common runtime errors at compile time, and additionally, how understanding the concepts behind Rust's safety features can sharpen your Python...

Software estimation: False sense of certainty (sps25)

It has been known since the 70s that developers tend to give very optimistic estimations. We prefer to have exact numbers, even if that means they are wrong most of the time. In research, developers admitted that they believe their managers will see them as less competent if they provide estimates with huge margins. But mathematically speaking providing a wider min-max interval means you will be right more often. So, maybe it isn’t really accuracy that businesses and people are looking for. Maybe estimates are needed for the sole purpose of risk aversion. Risk...