Q&A: Tobias Hagemann talks about storing sensitive files in Nextcloud

Tobias Hagemann is an iOS app developer and designer. He is also a co-founder and CEO of Skymatic, where he focuses on creating software like Cryptomator. Hagemann will be delivering a lightening talk at the upcoming Nextcloud conference where he will talk about how to store sensitive files in your Nextcloud by using Cryptomator’s client-side encryption.

We talked to Hagemann to learn more about his talk.

Why do you think encryption is important?
Encryption is important as it protects your data and communication from unauthorized access by illegitimate parties. It is used to secure corporate secrets, guard against identity theft, or just to protect your privacy. If encrypted data falls into the hands of someone illegitimate, this person will not be able to read it. Not using encryption would be comparable to not locking your house – with the difference that the house can be entered from all over the world.

Is there any built-in encryption in Nextcloud? If not, what solutions are out there?
Nextcloud offers server-side encryption, see this for reference. However, there is no built-in solution for client-side encryption in Nextcloud. Cryptomator might be a strong contender for becoming just that as it’s easy-to-use, multi-platform, and open-source. Client-side encryption solves privacy issues by giving you full control of your data so that you don’t have to trust the server or its administrators.

What will be the highlight of your talk? Who should attend it?
You’ll learn how you can store sensitive files in your Nextcloud by using Cryptomator’s client-side encryption. You will get a brief overview of Cryptomator’s security architecture. We will go into more detail in the workshop afterwards.

Anyone from being curious on how to store sensitive files in the cloud to being enthusiastic about privacy is welcome to attend the talk. If you have deeper knowledge of Nextcloud’s storage feature, especially of its web browser integration, you’re more than welcome to join us for the workshop.

What exactly is Cryptomator?
Cryptomator is a client-side cloud storage encryption software by the German startup Skymatic. The software automatically encrypts files on your device before they are uploaded to a cloud storage. As Cryptomator is open-source, it solves the issue of trust that many institutions used to have when considering the use of cloud storage solutions. For the combination of transparency and usability, Cryptomator was awarded the CeBIT Innovation Award for Usable Security and Privacy in 2016. The software is available for all major operating systems (Windows, macOS, Linux) and on mobile devices (iOS, Android).

More info is available on cryptomator.org

You will also be conducting a workshop, can you tell us more about the workshop?

The workshop’s focus is on Nextcloud’s storage feature. We will explore Cryptomator’s encryption scheme and security architecture in full detail. We will cover common cloud storage scenarios and how Cryptomator handles them including its limitations.

Goal of this workshop is to draft an architecture or concept on how Cryptomator could be integrated into Nextcloud in order to achieve client-side encryption in a web browser.