2024-09-21 –, LAB 4
Matrix has a lot of keys. These keys all provide different functionality. If you have ever wondered why do we need all of them, this is the talk for you! This talk is going to focus on Matrix cryptographic key infrastructure: the keys that we need to provide a good user experience, but not message security.
Matrix has a lot of keys. There are keys for devices, keys for users, keys for messages, keys for backups, keys for the keys to the backups, etc. All of these keys provide different functionality. There are a lot of resources explaining message keys (with the olm/megolm protocol), but not as many explaining the rest of the keys in the Matrix protocol. This talk intends to be an overview of those keys which provide infrastructure for key backups, key sharing, device verification, and cross-signing.
This talk is designed for people with a basic understanding of the various Matrix features. You do not need to know anything about cryptography to gain value from this talk. I will cover some basics of cryptosystems, but at a very high level cursory level in order to motivate the selection of key algorithms.
I'm a software engineer at Automattic working on Beeper. I've been using Matrix since 2018 and have been working on Matrix projects professionally at Beeper since 2021. I work on the Beeper Platform team maintaining backend infrastructure, bridges, and our Go client SDK.