Fair loss-tolerant and quantum-memory-loss-sensitive SCF protocol based on EPR pair

In this paper, we present a novel loss-tolerant quantum strong coin flipping (SCF) protocol. Compared with previous qubit-based loss-tolerant SCF protocols, we introduce the EPR pair to keep our protocol loss-tolerant while trying to push down the bias. In addition, losses in the quantum memory storage besides those in the quantum channel are also taken into account. We obtain the bias in the fair scenario as a function of p, where p is the probability that the particle in Bob’s quantum memory storage is lost, which means our bias varies as the degree of losses in the quantum memory storage changes. We also show that the bias decreases with decreasing p. When p approaches 0, the bias approaches 0.3536, which is less than that of all the previous loss-tolerant protocols. Details of both parties’ optimal cheating strategies are also given and analyzed.