By testing nonlocality, the security of entanglement-based quantum key distribution (QKD) can be enhanced to being 'device-independent'. Here we ask whether such a strong form of security could also be established for one-way (prepare and measure) QKD. While fully device-independent security is impossible, we show that security can be guaranteed against individual attacks in a semi-device-independent scenario. In the latter, the devices used by the trusted parties are non-characterized, but the dimensionality of the quantum systems used in the protocol is assumed to be bounded. Our security proof relies on the analogies between one-way QKD, dimension witnesses and random-access codes.
@article{arxiv.1103.4105,
title = {Semi-device-independent security of one-way quantum key distribution},
author = {Marcin Pawlowski and Nicolas Brunner},
journal= {arXiv preprint arXiv:1103.4105},
year = {2011}
}