Private states are those quantum states from which a perfectly secure cryptographic key can be extracted. They represent the basic unit of quantum privacy. In this work we show that all states belonging to this class violate a Bell inequality. This result establishes a connection between perfect privacy and nonlocality in the quantum domain.
@article{arxiv.0911.3274,
title = {Perfect Quantum Privacy Implies Nonlocality},
author = {Remigiusz Augusiak and Daniel Cavalcanti and Giuseppe Prettico and Antonio Acin},
journal= {arXiv preprint arXiv:0911.3274},
year = {2015}
}