Interview with Dijkstra Fellow David Chaum

David Chaum (1955) was awarded the Dijkstra Fellowship for his groundbreaking work in privacy and cryptology and the development of digital currency, which laid the technological basis for blockchain and bitcoin. This interview appeared in CWI’s staff magazine in April 2020.

Publication date
6 May 2020

David Chaum (1955) was awarded the Dijkstra Fellowship for his groundbreaking work in privacy and cryptology and the development of digital currency, which laid the technological basis for blockchain and bitcoin. In April 2020, we interviewed him about his life and his past and current activities.

David Chaum
David Chaum

Could you tell us something about your youth?

I grew up in Los Angeles, programmed my first computer using toothpicks to push pre perfed holes out of Hollerith cards that were submitted to a computer with one-week turnaround, taught programming at a local junior college while in high school, and later kind of dropped out of high-school to sneak into UCLA computer science courses. At Berkeley I started IACR when the NSA started trying to block conferences on cryptography.

What are you most proud of in your work at CWI?

Our Crypto Group spanned the full academic spectrum: undergraduates through post-docs and visiting professors, computer scientists and mathematicians. We held conferences for undergraduates, summer schools for graduates, monthly national crypto days, and international conferences. Alfred Hofmann of Springer once remarked to me that we had published more articles on cryptography than anyone, even still 5 years after the group stopped publishing! Of course the multiparty results are at the same time like Maxwell's equations and the Church-Turing thesis of cryptography, and it was thrilling to lead in these breakthroughs. 

When did you start your first company?

Sitting in my office at CWI one day, I was contacted by Rijkswaterstaat. They had a big problem. Highway-speed road tolls were the only way to solve the country's traffic problem, but it would not be acceptable without privacy. I put together a team of students that demonstrated a solution for them in 10 days: an eCash payment in a meter of road travel at 100km/hr highway speeds. We built it, partnered with Amtech for the radio link, and then this technology allowed DigiCash to make the first payment over the Internet at the first WWW conference in Geneva. We issued our own Cyber Bucks and then Deutsche Bank issued Deutschmarks using our eCash.

Could you briefly describe what you are doing ?

The xx network is the first online platform that allows people to communicate and exchange value without revealing information about their activities to third parties that could collect or sell their data. The xx network’s underlying blockchain is the first that does any of these things: includes metadata shredding (privacy technology I worked on at CWI), is secured by quantum-resistant cryptography, scales linearly with both transaction volume and number of users, and has “one user, one vote governance,” via sample voting that scales both with size of electorate and complexity of issues.

What are your plans for the future, and what are the challenges?

My plan for the future is to continue to focus on xx network through its launch as an autonomous blockchain. We are planning to launch our main net this year. A major focus will be growing the xx network community and putting people back in control of their information. 

Which important developments or breakthroughs do you expect in the next ten years in your field?

I expect that in the next 10 years a major breakthrough will be the evolution of direct democracy based on metadata shredding and sample voting.

Who inspires you from CWI?

Actually, Gene Lawler, my advisor for a while at Berkeley, intrigued me about CWI. Then Cor Baayen invited me to CWI. I always valued his friendship and enjoyed helping him launch ERCIM, European Research Consortium for Informatics and Mathematics. It was incredibly great to be able to hang out with them and so many greats like, regrettably just a few examples: Andries Brouwer, Paul Vitányi, Gilles Brassard, Lambert Meertens, and young researchers like Claude Crépeau and Jeroen van de Graaf.

What is your motivation?

My motivation is to help cryptography protect, as it uniquely can, human potential as it is unleashed.

What was the best advice you ever got?

Don’t even try to figure out why people do things in organizations.

Do you have a personal note?

Mokum, and CWI, gave me such a fantastic sense of freedom! Freedom from judgement, scientifically, with the urban anonymity of an expat, and in all things.

Do you want to say something to your colleagues at CWI?

I often tell young academics that the life of a graduate student is as good as it gets in terms of being able to pursue your academic interests. But being a group leader at CWI bests that everyday!

A number of the leading cryptographers of the world got their start at a two-week Crypto-Course David Chaum organized at CWI in Amsterdam, around 1986. Picture: D. Chaum.

(interview: Annette Kik)

More information

This interview appeared in CWI’s staff magazine We@CWI on 30 April 2020.