Improved Loss-Tolerant Quantum Coin Flipping

Abstract

In this paper, we present a loss-tolerant quantum strong coin flipping protocol with bias 0.359. This is an improvement over Berlin etal's protocol [BBBG08] which achieves a bias of 0.4. To achieve this, we extend Berlin et al.'s protocol by adding an encryption step that hides some information to Bob until he confirms that he successfully measured. We also show using numerical analysis that a we cannot improve this bias by considering a k-fold repetition of Berlin etal's protocol for k > 2.