I'm Kristof Verslype,

researcher, advisor & speaker


crypto, privacy & blockchain tech

© Eleni Maniati
I obtained my doctoral degree (PhD) of engineering at the University of Leuven, Belgium. My research focused on improving the privacy of the citizen by using cryptography. I'm currently working at the research team of Smals, which provides IT services to Belgian governmental organizations. Every day, I continue my quest for improving privacy with cryptography, which has become even more relevant since the publication of the GDPR.

At Smals, I also got the unique opportunity to develop a deep understanding of blockchain technology, including bitcoin and smart contracts. My academic background in cryptography and privacy turned out to be a perfect match, since it helps me to approach this young and heavily hyped technology in a scientific and balanced way. Since I have no positions in cryptocurrencies, blockchain-only companies or banks, there is no pressure to abandon this approach.

I use my year-long experience and knowledge to:

  • Innovate
    by devising advanced & creative solutions
  • Review

    proposals on their privacy, sec­urity, scalability, ...

  • Share

    knowledge & insights in articles, seminars, ...

  • Advise

    organisations e.g. in their blockchain strategy

In my private life, I love photography and I'm passionate about the Greek nature, language, culture & food.

My CV can be found here.

© Kelsey Ruys
University of Leuven
In 2004 I obtained a Master in Informatics at the University of Leuven (with distinction) with a thesis entitled: "Group and Ring Signatures", which are two related cryptographic primitives to create digital signatures in the name of a group.

In 2009, I was awarded, as PhD student, the Best Paper Award from SECRYPT, the international conference on security and cryptography for my paper: Service and Timeframe Dependent Unlinkable One-Time Pseudonyms.

In 2011, I obtained at the University of Leuven my PhD of Engineering with a dissertation entitled: “Improving privacy in applications by managing the disclosure of personal properties”. The aim was to develop and facilitate the development of applications whereby the certified personal user data that are being disclosed to the service provider are minimized, while the latter still has sufficient information and guaranties to offer its services. Today, this is called self-sovereign identity. One of the key cryptographic tools in my reserach were attribute-based credentials, as well as the underlying zero-knowledge proofs.

The list of my academic publications can be found here.

During my time at the university, I have been teaching various courses for various student groups and I have been coaching theses of several master students, of which two obtained later a PhD as well. Occasionaly, there is still collabaration between the University of Leuven and me at Smals. I coached, for instance, during the academic year 2016-2017 a master student on his thesis "Kruisen van persoonsgegevens met maximale bescherming van de privacy (Linking together Personal Identifiable Data with Maximal Protection of the Privacy)".

In 2015 I passed the online Coursera course Cryptography I offered by Stanford University. I got 100 % (with distinction).
Smals (Belgian Government)
In 2011, I joined the research team of Smals, which provides IT services to Belgian governmental institutions. As researcher, I study new concepts and try to solve with them technical challenges within government context. Furthermore, Smals Research is doing knowledge transfer inside the government under the form of presentations and advise.

My main occupations so far are
  • Data protection and cloud strategies for governments
  • Anonymisation and pseudonymisation of PII (Personal Identifiable Information)
  • Bitcoin, blockchain and smart contracts
  • Advanced cryptographic techniques
I introduced the first technical knowledge about blockchain and smart contracts into the Belgian federal government.

The government processes many personal data, which poses privacy challenges. This issue comes back in all the research i'm doing. I try to come up with new and innovative cryptographic concepts to protect the privacy of the citizen. I give you below an idea of three of these proposed innovations.

Processing Prescriptions with a Blockchain

Processing a medical prescription involves a complex information flow which can be eliminated by putting the prescriptions on a blockchain. This solutions also minimizes reliance upon central authorities and intermediary parties. However, strong guarantees are required to protect the privacy of the patient and the business information of other involved entities such as the physician, the pharmacist and the insurer. Therefore, the solution is designed in such a way that even public disclosure of the blockchain does not reveal any privacy-sensitive or confidential information.

Combining Personal Identifiable Information from Multiple Sources

What if a research team wants to analyse large sets of personal data? Say it needs medical, financial and demographic data of all citizens with a wage of at least €40.000, born after 1990 and who are self-employed as a secondary activity. Data sets managed by different government institutions would need to be linked together. Such requests are common, and any government should be able to answer them. Yet is it possible with due respect for the privacy of citizens in an era of big data? By making records in different data sets unlinkable, we were able to push the boundaries of what is technically feasible. This brings the security to a higher level and gives the control of the data back to the government organizations that own it.

Exchanging PII with Insurers while hiding mutuality membership

The Crossroad Bank of the Social Security (CBSS) needs to be able to send to and receive from the insurers personal identifiable data (PII) of citizens. For the insurers, it is unacceptable that the CBSS learns the mutuality to which a citizen is affiliated. Now, an intermediary party, managed by the seven mutualities is used. We came up with a solution that can do the same, but without the need to trust an intermediate party.
I am regularly asked as a speaker. Besides my public talks, which are listed below, I also frequently give non-public talks and courses. Usually, my topics are about:

Upcoming Talks

Smart contracts – Juridische implicaties van een blockchain innovatie

Seminar by Lexalert

The potential
of Blockchain
in the Public Sector

Talk at Public Sector Congress 2018
FPS Justice

Past Talks

Blockchain & smart contracts - A Technical Introduction

Guest Lecture, Dept. of Computer science, University of Leuven
Technology Campus Ghent, Dutch

Blockchain & Smart Contracts – Inleiding voor juristen

Course for Larcier Group
Maison de l'Automobile, Brussels

Blockchain & Toepassingen - Een verkenning 'onder de motorkap'

Workshop SAI
Van der Valk Hotel, Diegem

Blockchain Innovation:
Opportunities & Challenges

Guest Lecture, University of Leuven
Faculty of Economics, Campus Brussels, English

Blockchain –
a New Tool for
the Auditor?

Seminar by ISACA
University of Leuven, Campus
Brussels, English

Blockchain & Smart Contracts – Inleiding voor juristen

Course for Larcier Group
3Square Ghent

Blockchain & smart contracts – Technologie en toepassingen

Evening Conference by SAI
Crowne Plaza Hotel, Antwerp

Bitcoin, blockchain & smart contracts – Impact op de juridische sector

Seminar by Lexalert

Blockchain & Smart Contracts. Introduction & Practical Use Case

Seminar for Brussels Legal Hackers
The Sister Brussels Cafe, Brussels

Medical Prescriptions
on a
Public Blockchain

Talk at Techorama 2017
Kinepolis, Antwerp

Linking together personal data in the era of Big Data and GDPR

Talk at Infosecurity 2017
Brussels Expo

Blockchain & Smart Contracts

Talk in auditorium of Smals

Privacy Vs. Analytics

Talk in auditorium of Smals

I'm writing regularly articles about my professional interests.
Unfortunately mostly in Dutch for the moment.
More articles are scheduled. Stay tuned!

Linking Together Personal Data in the Era of Big Data & GDPR

In May 2018, the much-discussed GDPR will be enacted. Besides identified data and anonymous data, the European regulation introduces a new category of data, called pseudonymous data. This articles presents an approach, based on cryptographic pseudonyms, that can help governments to become GDPR ... Continue reading →

Voici les 7 mythes du Bitcoin, une pseudo-monnaie qui est "détournée par la spéculation"

Le Bitcoin, vous en avez déjà entendu parler. Mais savez-vous exactement ce que c'est, et comment ça tourne ? Dans les allées du plus grand salon belge dédié à la cybersécurité, nous avons assisté à une présentation d'un expert belge, Kristof Verslype, qui démonte en 7 points les mythes circulant autour de cette "monnaie" virtuelle... Continue reading →

Enkele valkuilen met smart contracts in Ethereum

Ethereum is het meest populaire blockchain-platform voor ‘smart contracts’. Dit zijn in feite stukjes code die gedistribueerd worden uitgevoerd binnen een blockchain-netwerk. Voor iemand met een beetje programmeerachtergrond ziet een smart ...contract in Ethereum eruit als normale code. Toch zijn er specifieke valkuilen ... Continue reading →

Blockchain & Smart Contracts - FAQ voor Juristen

Onderstaand artikel werd geschreven op vraag van Larcier Group, de autoriteit voor juridische vakliteratuur, en verschijnt in hun magazine Emile en Ferdinand. Het artikel tracht te antwoorden op een aantal vragen rond blockchain die leven bij heel wat juristen. Continue reading →

Bitcoins vreten steeds meer energie: equivalent van 39% van Belgische stroomverbruik

Voor bitcoins moeten zware computers en servers overuren draaien, en dat vreet energie, zeker nu de koers van de bitcoin onlangs scherp is gestegen: momenteel gaat het naar schatting om het equivalent van 39 procent van het totale … Continue reading →

‘De bitcoin is een ecologische ramp’

Voor de ontginning van de virtuele munt bitcoin is in één jaar tijd ongeveer evenveel elektriciteit nodig als wat half Vlaanderen in dezelfde tijdsspanne verbruikt. ‘Een zware ecologische prijs om betalingen uit te kunnen voeren zonder de tussenkomst van een bank.’ … Continue reading →

Bitcoin – Van Experiment tot Ecologische Ramp

Op 22 mei 2010 kocht een software ontwikkelaar 2 pizza’s voor 10 000 bitcoins. Vandaag zijn 10 000 bitcoins ongeveer 40 miljoen dollar waard. Die astronomische stijging spreekt tot de verbeelding. Toch heeft dit succesverhaal een nauwelijks belichte keerzijde … Continue reading →

Blockchain - Wervelwind in de audit wereld?

Blockchain is een baanbrekende technologie. Het is de ruggengraat van Bitcoin, de digitale cryptomunt waarmee u geld kunt transfereren zonder dat daar een bank aan te pas komt. Die blockchain-technologie kan ook ingezet worden in andere domeinen om het belang … Continue reading →

Open en minder open blockchain netwerken

Blockchain zag in 2009 het licht met de lancering van Bitcoin. Het Bitcoin netwerk is extreem open en transparant; iedereen kan minen1, iedereen kan transacties publiceren en iedereen kan de volledige inhoud van de blockchain zien. Daarenboven kan iedereen wereldwijd … Continue reading →

Beslissingsmodel: Wanneer blockchain gebruiken?

Blockchain wordt gezien als een disruptieve technologie die de komende jaren een grote impact zal hebben, ook in overheidscontext. Veel bedrijven en overheden zullen dan ook geconfronteerd worden met de vraag of blockchain technologie een meerwaarde kan hebben bij de … Continue reading →

Smart Contracts – Autonome code op een blockchain

In een eerdere blogpost hadden we het over Bitcoin en blockchains. Indien deze termen u vertrouwd in de oren klinken is de kans groot dat u ook al de term smart contract heeft horen waaien, wat ook wel blockchain 2.0 genoemd wordt. Deze blogpost gaat hier dieper op in. … Continue reading →

Keyless Signature Infrastructure (KSI) – Een alternatief op PKI voor digitale handtekeningen?

Een public key infrastructure, of kortweg PKI, wordt algemeen gezien als de enige manier om digitale handtekeningen te plaatsen. Toch heeft Estland al acht jaar een alternatief dat luistert naar de naam Keyless Signature Infrastructure, of kortweg KSI. Hoe werkt … Continue reading →

Blockchain, het kloppend hart van Bitcoin

Bitcoin is de eerste gedistribueerde cryptocurrency, of anders gezegd, de eerste munteenheid die voor financiële transacties dankzij cryptografie geen nood heeft aan centrale partijen, zoals traditioneel de banken. Het kloppend hart van het in 2009 gelanceerde Bitcoin is de blockchain, … Continue reading →

De Cloud is als... Elektriciteit? Of toch eerder Goud?

Het gebruik van cloud diensten wordt vaak vergeleken met het gebruik van electriciteit. Toch mogen we deze vergelijking niet te ver doortrekken. Wanneer we spreken over gevoelige overheidsgegevens lijkt een andere vergelijking accurater. Vergelijking 1: Cloud & Electriciteit Gebruik van … Continue reading →

Big data & krakend ijs onder anonimisatie

Inleiding Elk bedrijf bezit wel persoonsgegevens. Denken we maar aan winkels, banken en transportbedrijven. Deze gegevens kunnen interessant zijn voor andere doeleinden dan waarvoor ze initieel verzameld werden. Dit kan binnen het eigen bedrijf zijn, maar gegevens kunnen ook voor … Continue reading →