On Friday 30 September 2022 Christian Schaffner gives his inaugural lecture as professor in theoretical computer science at UvA. He has been fascinated by cryptography since childhood and specializes in quantum cryptography. This year he also became the new group leader of the Theory of Computer Science (TCS) at UvA informatics institute IvI, located in UvA's LAB42. Schaffner will remain working as a researcher at QuSoft, which is currently located at NWO institute CWI.
‘To simply illustrate what cryptography is about, I will speak during my inaugural lecture a few sentences in Swiss-German’, says Christian Schaffner, himself of Swiss descent. ‘Then I know that only the few Swiss people in the audience will understand me, but non-Swiss people not.’ Of course, speaking in Swiss-German in general is not so safe after all if you only want to communicate with one person, but it illustrates the point. Schaffner: ‘You choose a form of encoding and you open a channel of communication with whomever can decode it.’
In his inaugural lecture entitled ‘A cryptographic view on computer science’ Schaffner views computer science through the lens of cryptography, touching on theoretical concepts like the difficulty of solving computational problems and how these are used in a cryptographic context.
Cryptography goes back millennia in history. In the middle of the 20th century, the invention of the computer revolutionized the field. However, the predicted arrival of the quantum computer will give cryptography a completely new twist, and that’s the focus of Schaffner’s own research. Important current cryptographic standards that allow us to do secure online banking or shopping can be cracked with a sufficiently powerful quantum computer.
‘This is not just a problem in the future’, says Schaffner, ‘but it is already a problem now.’ How can that be? Well, malicious persons can simply store secure messages, wait until a quantum computer becomes available, and then still crack the old, encrypted messages. Schaffner: ‘Sometimes you will not gain anything from it, but sometimes you will gain important secrets. If the law requires certain information to be kept secret for twenty years, like state secrets or medical data, we are already in trouble now.’
Quantum cryptography is like a double-edged sword: on the one hand it can break classical encryption (such as RSA or Diffie-Helman public-key cryptography), on the other hand it can make entirely new quantum encryption possible, safe against attacks with a quantum computer. Schaffner made important scientific contributions on both sides. With his appointment as a professor, the university gives a new boost to a field which is already strong in the Amsterdam area. Schaffner is also the chairman of the innovation hub Quantum.Amsterdam, founded by the Dutch research center for quantum software and applications QuSoft, Centrum Wiskunde & Informatica (CWI) and UvA.
Schaffner is also affiliated with QuSoft, the Dutch research center for quantum software & technology. Launched by CWI and UvA in December 2015, QuSoft builds on the institutions’ excellent track record in quantum computing and quantum information.
Schaffner received a diploma degree in mathematics from ETH Zürich (Switzerland) in 2003 and a PhD degree in computer science from Aarhus University (Denmark) in 2007. After being a postdoctoral scholar at Centrum Wiskunde & Informatica (CWI) in Amsterdam, he joined the UvA Institute for Logic, Language and Computation (ILLC) as assistant professor in 2013 and become associate professor in 2018. He is also a senior researcher at QuSoft, the Dutch research center for quantum software, hosted at NWO institute CWI. Schaffner obtained a NWO VENI grant in 2010 and a NWO VIDI grant in 2015. He has served on numerous program committees for conferences, PhD and NWO grant committees as well as on the steering committee of QCrypt. He is the chair of the talent and outreach committee of the Quantum Software Consortium and chair of the network organization Quantum.Amsterdam, the innovation hub for quantum software, technology, and applications.