Christian Schaffner, from the Centrum Wiskunde & Informatica (CWI) in Amsterdam, has been awarded a Veni grant by the Dutch Organisation for Scientific Research (NWO). He receives this grant for his project ‘Beyond Quantum Cryptography Key Distribution’, which deals with new applications for quantum cryptography (security obtained by quantum computing techniques). It is technically very challenging to store information in quantum particles like photons. Schaffner investigates if he can use this technical difficulty as an advantage in the development of provably secure systems. He studies communications and computations between two parties that do not trust each other, e.g., during a merger of companies or in electronic auctions. The results can be applied to secure identification and e-voting.
Provable security
Many of the existing cryptosystems are based on mathematical assumptions that are still unproven. An example is the assumption that finding the prime factors of a large number difficult, which is used by the RSA cryptosystem to secure Internet data. If a method for efficient factoring is established, e.g., using a large quantum computer, the cryptosystem is also much easier to ‘break. In contrast, quantum cryptography can provide security that is solely based on physical assumptions, such as the correctness of quantum mechanics.
Until now there was no quantum cryptographic method for secure computation between two parties who do not trust each other, e.g. when companies are considering a merger. Until recently it was thought that quantum cryptography had no advantage over traditional methods in this respect. However, the researcher showed that there are more possibilities, if one only assumes that it is very difficult to store quantum information for a long period. In his Veni project Schaffner wants to formalize the technical difficulties in building a quantum computer. Eventually he wants to prove that it is either possible to build a large-scale quantum computer, or to know the reasons why it cannot be built, and use these for cryptographic purposes. In the future, the techniques developed here can also be used to provide innovative, alternative solutions to traditional problems. So the spectrum of quantum cryptographic applications broadens. This is nice for users: the more different safety measures, the better the protection.
Christian Schaffner (1978, Switzerland) works as a postdoctoral researcher in the research group Algorithms and Complexity from Harry Buhrman at CWI. This group is a global leader in the field of quantum computing. The Veni grant is a prestigious grant for young researchers, allowing them to do research for three years. Obtaining this grant is an important step in a scientific career.
