Practical Quantum Coin Flipping

TL;DR

This paper demonstrates a practical quantum coin flipping protocol that outperforms classical protocols in security, accounting for real-world experimental imperfections, and is feasible with current technology using simple laser pulses.

Contribution

It introduces a practical quantum coin flipping protocol that surpasses classical security limits and is implementable with existing technology and standard optical components.

Findings

Achieves better cheating probability than classical protocols for up to 21 km channels.

Compatible with current technology using attenuated laser pulses.

Accounts for all major experimental imperfections in implementation.

Abstract

In this article we show for the first time that quantum coin flipping with security guarantees that are strictly better than any classical protocol is possible to implement with current technology. Our protocol takes into account all aspects of an experimental implementation like losses, multi-photon pulses emitted by practical photon sources, channel noise, detector dark counts and finite quantum efficiency. We calculate the abort probability when both players are honest, as well as the probability of one player forcing his desired outcome. For channel length up to 21 km, we achieve a cheating probability that is better than in any classical protocol. Our protocol is easy to implement using attenuated laser pulses, with no need for entangled photons or any other specific resources.