Researchers: Kirsten Kanneworff, Mio Poortvliet, Thomas Steenbergen

Quantum Key Distribution (QKD) can secure a communication channel, but it can’t “authenticate” it. How can Alice be sure that she is communicating with Bob and not with some impostor? Next to physical meeting and exchange of cryptographic keys, verifying the geographical location of a party is possibly the only useful option. This can be done by Quantum Position Verification (QPV).

By combining principles from (i) special relativity, which limits the speed of information transfer to the speed of light, (ii) quantum information, which provides information security by the no-cloning theorem, and (iii) computer science, in particular complex functions, we aim to realize QPV.

The setup: Two “verifiers” share a secret channel want to confirm the location of a “prover” P. The verifiers send quantum and classical information to the prover, the prover performs a particular task and returns the result, possibly also quantum information, back to the two verifiers. By analyzing the information and the timing, the position of the prover can be verified.