Practical quantum position verification – PraQPV

In recent years, novel technologies based on quantum communication such as quantum key distribution have made the transition from theory to reality. In this project, we will consider another important cryptographic task, namely quantum position verification. Quantum position verification is the principal cryptographic primitive for quantum position-based cryptography. Here, the idea is to use a party's position instead of, for example, a secret key as credential. Possible applications include increasing the security of online banking. It has been proven that secure position verification is impossible without quantum resources.

The aim of the project is to remove the last remaining obstacles towards a first experimental realization of quantum position verification.

The project's aims are three-fold: First, we will solve the practical challenges standing in the way of realizing the measuring protocol which is one of the first protocols proposed for quantum position verification (and for which the scientific coordinator is one of the co-authors of its security proof). The measuring protocol allows to do secure position verification with only a single qubit and is reminiscent of the BB84 protocol, but where the choice of basis is dictated by evaluating a classical function. Second, we investigate the entanglement cost of attackers in order to reduce the exponential gap between the best theoretical security guarantees and the best known attacks. Finally, we will study how quantum position-verification can be integrated into more complex protocols, considering for example device-independence and composability of protocols for position verification.

Thus, this project will contribute to making quantum position-based cryptography a reality.