Interview with Nathan Keyaerts

Thu 06 May 2021 10:36

Meet Nathan Keyaerts, an Erasmus exchange student from the University of Mons in Belgium. He is doing his master within cryptography and how to secure the communication between different IoT devices together with the research group Communication Systems and Networks at STC Research Centre.

Nathan Keyaerts i biblioteket
Nathan Keyaerts, Erasmus exchange student from University of Mons, Belgium

Tell me a little about your background?

I’m a student from the University of Mons in Belgium. I’m doing a master in informatics and management. It is a broad master that covers multiple topics within IT (Networks, Cyber-security, Databases, …) and teaches us some management skills to be able to lead teams of computer scientists. I am in the last year of my master (fifth year).

Why did you choose to make an exchange at Mid Sweden University in Sundsvall?

I always loved to travel as a child and come here in Sweden a few years ago to do a trek. I loved the country for its nature and the mentality of the swedes that makes them in the top 10 for happiness.

As I started searching for an ERASMUS my research automatically went to Sweden. I didn’t want to go too much to the south as I wanted to live the long nights and the freezing cold. Nor wanted I to go too much too the north to avoid dying before the spring. Sundsvall was perfectly located. To add to this, a friend of mine who came here before me warmly recommended it to me. So, I started contacting the teachers he had had over here to see if they were interested to have me work with them in the Information Systems and Technology (IST) department. Luckily, they proposed a very interesting subject to me for my thesis. So, I did not hesitate much to choose the Mid Sweden University.

When did you come here?

I arrived here in the middle of January and started my work at the begin of February. I wanted to start with a bit of a head start to allow me to visit the country once the weather allowed it.

I should finish my thesis mid-June but plan on staying here until the end of July to take some vacations once I finish all the work. I hope to use this time to do some hiking around here.

Nathan Keyaerts presenterar sitt arbete vid datorn

What have you done so far in your work?

It is a bit technical, so I’ll break it down but I’m trying to secure the communication between different IoT devices in a novel way.

In cryptography there are two main ways to secure communications: symmetric and asymmetric cryptography. The first uses a secret “password”, named secret key, that both the sender and receiver must know. The problem here is that at some point this secret must be shared. Which is a problem since if someone reads that message, they also know the secret key and will be able to read all the messages.

Symmetric Cryptography


This is solved with the second type, the asymmetric cryptography. In this case, there are two keys: one public and one private. They are both created on one computer. The public key can be used to encrypt a message but once it is ciphered it is impossible to use that public key to go back, this is called a “one-way” function. Only the private key (kept secret of course) allows that. This means that if I send the public key to people, they can encrypt a message that only I, with my secret private key, will be able to bring back to its original form.

Asymmetric Cryptography

Usually, only one public key is associated to one private key. My work is to use what is called Lattice cryptography to ensure that more than one private key can be used with one public key. In this way someone can send a message (with the unique public key) to multiple computers at the same time in a safe way and each one of them will be able to read that message.

What do you think about the university and Sundsvall?

I really love the university! The buildings are so nice. I sometimes just wander around in the different buildings to see new places. Also, the teachers are always open to help even if they barely know me. I, sadly, have not had the chance to meet a lot of students with the pandemic and since I do not have any course. But the few I met where always helpful and really nice to talk to.

As for Sundsvall, I love it here. It is a refreshing change from Belgium. There are a lot of activities close by, like the skiing slopes at Sidsjon or the view and park at Norra Berget. Each week I have had activities to do with the other ERASMUS students. And I’m sure I haven’t done half of what is possible.

I guess it has been a different experience with the pandemic. How has it worked for you?
To be honest, I come from a country where I lived through a lockdown and a curfew so coming here was a choc. Sometimes I would even forget that the pandemic was still happening. Apart from the activities organized for the international students by the student’s union, I haven’t missed that much.

I am thankful to the solid group of ERASMUS student around me that try to make the most out of our trip. Of course, we can’t do everything we want, but we had our fair share of fun!

Anything you like to add?

Not really, I just want to thank the university from the bottom of my heart for this wonderful adventure! And hope to make the most of the last two months.


The page was updated 5/6/2021