We propose a local scheme to enhance the security of quantum key distribution in Ekert protocol (E91). Our proposal is a fair sampling test meant to detect an eavesdropping attempt that would use a biased sample to mimic an apparent violation of Bell inequalities. The test is local and non disruptive: it can be unilaterally performed at any time by either Alice or Bob during the production of the key, and together with the Bell inequality test.
@article{arxiv.1004.1242,
title = {A Fair Sampling Test for Ekert Protocol},
author = {Guillaume Adenier and Noboru Watanabe and Andrei Yu. Khrennikov},
journal= {arXiv preprint arXiv:1004.1242},
year = {2017}
}