Interview with Professor Vincent Rijmen: Encryption Innovator at KUL

If you’re one of those people that have at one point wondered how the sensitive information that circulates around the world is encrypted, you may have also wondered who invented that encryption algorithm. Well, the standard for encrypting sensitive information is the AES, or Advanced Encryption Standard. It was chosen by the NIST, National Institute of Standards and Technology and by the US government to protect classified information, and is implemented in software and hardware throughout the world to encrypt sensitive data.

Why is that relevant? It’s relevant because one of the two “fathers” of the AES, also known as the Rijndael cipher, is a professor of applied algebra in the department of engineering here at the KUL. His name is Vincent Rijmen, and his office is covered in his kids’ drawings.

So how did a Belgian man from the small town of Leuven become one of the rockstars of cryptography? “My main interest was mathematics when I was a teenager. I liked to do mathematics and I had very good teachers who were very enthusiastic about their field, so originally my plan was to become a mathematician at university. But then, when I turned 17, computers started to become available to people. Before that, no one had a general-purpose computer at home. And so I became fascinated by computers, and moved to study engineering. At that time, engineering was also much more mathematical than it is now. So while studying, I’d say I moved slightly away from mathematics, and more into electronics engineering. I’m interested in that parts of electronics engineering that also looks at and works with computers so not the real, say, “hard-core” soldering of transistors. Basically, I enrolled in the field of computer security, because at that time, as a student it was not sure that you’d get a job after studying engineering, because at that time there were too many engineers. And so there was an opportunity to stay here and go into cryptography and I took it and only then I got really enthusiastic about it. And so, if you look around the world, many people who do computer security are not really interested in mathematics, so, me and Joan Daemen were not exactly unique, but rare, people who were interested in mathematics and computer security. So that’s also what we tried to pour in our research on the Rijndael algorithm. And then we also had a bit of luck, because when I finished my PhD, exactly then the NIST issued this call for new encryption algorithms. And so we were fully prepared because my PhD had been about this and so now I could put it into practice. Joan was motivating me while also working in a company, but he was very interested in this. And so there were many other teams in the world working on submissions, but it was something we had studied so we only had to put in practice. And that’s what we did. And I also think we had a good background here, because we were interested in mathematics and we also knew about practical problems, because some researchers never encounter people from the industry and never actually know what are bottlenecks that need to be solved. And in the department in electrical engineering there is a lot of contact with the industry and so that allowed us to make a proposal that was fundamentally good in theory and also good in practice. Then yeah, after a few years we won this competition.”

As someone that got an autograph from professor Rijmen when he was my algebra professor, I couldn’t help but wonder about the time after the Rijndael became the AES. If it ever had any impact on his life, on his family, even on his mindset. “The years after it, especially in the beginning, the first two years were incredible. We were just travelling all over the world, giving the same presentation, and even though it doesn’t take long from the KUL to reimburse travel expenses I was always going into debt because of all the travelling. And then after a couple of years, you awake from that, and you say I have to move on from this, because you realize you’re always giving the same presentation again and again and again and people start to ask, “but don’t you have something new?”, and then you realize you don’t have time to waste. And so we got calmer with the travelling. And then we moved to Austria with my family, to Graz. Then after a couple of years I returned to work and live here. I actually never dreamed of becoming a professor or something like that. There was also a time after my PhD that I thought academia was not something for me.”

Of course, as a first year student, I was too shy to actually ask my professor for an autograph so I had my very nice TA to get it for me. He took my algebra book and gave it to professor Rijmen to sign. I remember the TA telling me how professor Rijmen had told him he used to have a special pen just for autographs, but that it had been a while since he had last used it, and wasn’t able to find it for my autograph. So you can see, his post-AES travelling has calmed down a lot, but I bet in the beginning it must have had quite an impact on his family life. One of the things I really remember from his lectures (besides the math), was that his laptop wallpaper was a picture of two of his daughters. I remember that because not many professors have family pictures on their laptops, especially the laptops that they use for teaching, and it struck me as something that really showed his personality as a family man. “When I was travelling all the time my wife had to be … patient let’s say. A couple of years ago I took the decision to cut down my travelling to 3-4 times a year because I have 4 children, and yeah, you realize soon that they grow older and that I could keep my wife sitting at home but then we shouldn’t have married in the first place. So you have to make a big choice there. I have colleagues that made the opposite decision and dedicated themselves to their work, but then I think that you can’t have the same kind of family life that I’d like to have. And when we moved to Austria it was also a career decision. I don’t know if you know this, but very few Belgians move away in their lives, and if they do, it’s to the next street. Maybe to illustrate this, for a time we lived in Wijgmaal, and my wife is from Heverlee and I am from Kessel-Lo, and my neighbors would ask why we’d bought a house there because neither of us really belong here. But I think moving to Austria was good, because it made us as a family unit closer to each other.”

With him being such a successful engineer, you’d probably wonder how much he had to study and work to accomplish so much in his professional life. “Not a lot actually. So yeah, I think sometimes it’s a handicap, because sometimes I’d get impatient with students when they didn’t understand something. Now it’s better, and I understand that for some other people it may take longer to understand something. I remember when I was in the second year, I got promoted to leader of the group as a boy scout which means that every weekend I was away and even some evening in the week I was busy with activities so that wouldn’t give me much time to study. I’d spend my free time between classes studying, and some evenings in the week but not much more. Of course, two weeks before the exams I would really start studying. But that was it. My younger sister re-used some of my books and always asked if I’d actually read them, because for some courses, I’d only have to read the book once. So I think it has come easy for me.”

As such an accomplished man with a natural genius, he is a very family-oriented and down-to-earth man. Most “geniuses” you see on TV are the complete opposite of the one I got to interview for this article. Of course, some of these personality traits are often overplayed, until the character becomes a caricature. “Often these shows and movies put a kind of picture that is not so close to the reality. They paint a caricature of the people in science, by portraying them all as autistic people or awkward people. Actually we have very few autistic people here because they don’t get through the education system in this country. But of course the TV shows and movies have to try and rake in audiences, so they have to play the most noticeable character traits of people to make the shows sell. And at info sessions we have to work to show people that this image is not correct because sometimes it frightens people off.”

For someone that works in the field of cryptography, the rise of social media must have had quite a big impact on his work. “Sometimes it puts your feet back on the ground. Because you worry all about privacy and protecting people’s data, and then you see what people put on social media. Apparently people think that writing something on social media is like talking one on one. They write something on their Facebook wall and they think that only 3 people will read it, they forget how many people they have in their friend lists. And then you sometimes start to think “why am I actually worrying and trying to make the internet more secure, because people clearly don’t use the security”. I mean banks use it, and people know that banks need to have secure communication. We still need people to realize what the potential problems of this behavior are. And until then we’ll have a difficult time making people use the products that we make. Something that people don’t understand is that those things that are posted online, live on forever.” Some of you may think his way of thinking about social media is paranoid, but, keep in mind, when the ugly concert pictures of Beyoncé came out online, they never disappeared, even after she got lawyers involved. So it is true that what goes online, stays online forever.

Has this affected his relationships with people? Or how he interacts with people? “People sometimes tell me I’m suspicious. Well I always worry about the security of mechanisms. Maybe it’s a bit of a farfetched example, but I was for two months in Paris for research and I was paid a grant. And you know, the bureaucracy there is incredible. So in order to get this grant, I needed to give my bank account. But not me giving my bank account, the bank making a statement in a certain form confirming that yes this is my bank account. And I told them that this type of form does not exist in Belgium. So then I asked what happens if I don’t give this form. They said that the grant will be sent in a bank check via postal mail to the address I had given them. I asked them whether they needed any confirmation that that was actually my address and they said no, they’d just send it to any address I’d supply them. And as a cryptographer you always think of the what ifs of situations. Like, okay I’m doing it this way, but what if someone does it that other way? And you try and make everything secure but the back door is always open. Sometimes it also makes you a bit cynical. For example when you’re sitting in a committee, and you start talking about a proposal and everyone starts saying positive things, you start to wonder why they’re saying all these positive things. Do they really feel positive about the proposal or do they just have their own agenda? So sometimes I have to say to myself, “Vincent you have to take this easy, say what you think and assume that others are just going to say what they think”. So I think sometimes you’re paranoid and you go into this profession, and other times, like with myself, reading all the papers from this profession makes you paranoid.”

Of course his work doesn’t leave him much time for hobbies, but while on the path of becoming a dedicated father and husband, he got some new hobbies along way. “So I was always a very enthusiastic boy scout. I was a boy scout until I was 30 years old, which is when I got married. But there’s an age limit to the boy scouts, so when you’re 35 you have to leave the boy scouts. And when I was a boy scout most people were leaving when they were 23-24 years old, so I stayed quite long compared to the rest. So I liked it a lot, and I spent a lot of time on it during all my studies. So at that time I didn’t have any other hobby except for that and role playing games like Dungeons and Dragons. But now I have my 4 children, which means their hobbies become my hobbies because I have to take them to their hobbies, maybe read up on their hobbies. For example, my son is a fencer, and I take him to fencing and I read up on fencing, and I think maybe I’d like to become a fencing referee. And the role playing game sometimes is like therapy, because certain barriers fall away and the people will act more like the small kid they are inside and you get to know them better.”

Of course, women in STEM is not a topic saved just for more classically male-dominated departments. “So I think the biggest problem now is that we’re still below some threshold. So I think sometimes women don’t want to be the first woman in a group of 15 men because they don’t want to be the only woman there. And I see that with my research field. I have some women PhD students and I get more requests, because they know that there already more and they won’t be the only one. And I see other colleagues, they only have 1 or 2 women PhD students, and they don’t get any other requests from women. There is also a bit a general problem I think because boys like to play more with abstract things than girls. A boy may see mathematics as a game, but a girl will want to know what meaningful thing will be achieved by her learning that thing, what real-world applications there are of it. So maybe we need to make the applications clearer to attract more female students. And because of the educational system, you need to go through that abstract learning and assignment phase to be able to go further in your field. So more girls than boys will say, I don’t study for fun, I study to help society and to see real-world results, so they will not go for STEM because of that. And even in the info sessions we have of the engineering department, we always try to make the real-word applications the center of the sessions so that people will see that they’re not just studying theory, but that that theory can also help society in some practical way. And of course, I think that the best research teams have both women and men. If you have only men, there’s a tendency for people to drop out more. Women will make the team work more together whereas if it were only men, they wouldn’t really listen to each other and they would each do their own thing parallel to each other.”

The advice he has for future and maybe current students of his field is to like it. “First of all, with all the hype about security and hacking, some people may think that they should go into cyber-security for the money. I don’t think that’s the right motivation, you have to really like it to be able to sacrifice so much of your time for it. And if you do like it, you should do it because the world needs people who understand math and technology because we’re getting more and more dependent on it because we get machines to do our dirty work for us.”

Kondelina Zegali