Towards experimental demonstration of quantum position verification using single photons

The geographical position can be a good credential for authentication of a party. This is the basis of position-based cryptography—but classically this cannot be done securely without physical exchange of a private key. Recently it has been shown that by combining quantum mechanics with the speed-of-light limit of special relativity, this might be possible: quantum position verification (QPV). Here we demonstrate experimentally a protocol that uses two-photon Hong-Ou-Mandel interference at a beamsplitter, which, in combination with two additional beam splitters and four detectors is rendering the protocol resilient to loss. With this, we are able to show first results towards an experimental demonstration of QPV.