Large payload bidirectional quantum secure direct communication without information leakage

TL;DR

This paper introduces a bidirectional quantum secure direct communication protocol that prevents information leakage and achieves a high transmission capacity of six bits per round, utilizing entanglement swapping of GHZ states.

Contribution

It presents a novel BQSDC protocol that ensures no information leakage and supports large payload transmission using shared GHZ states and entanglement swapping.

Findings

Prevents information leakage in bidirectional quantum communication.

Achieves a transmission capacity of six bits per round.

Utilizes entanglement swapping of GHZ states for secure encoding.

Abstract

A large payload bidirectional quantum secure direct communication (BQSDC) protocol without information leakage is proposed, which is based on entanglement swapping between any two GHZ states. Two remote authorized parties, Alice and Bob, can safely exchange their individual secret messages without worrying about the information leakage problem. Our protocol uses a shared secret GHZ state to overcome the information leakage problem. The shared secret GHZ state plays two roles in the bidirectional communication process: on one hand, it lets Bob know the prepared initial state; on the other hand, it is used for encoding Bob's secret messages. Moreover, our protocol can transmit six bits of secret messages per round communication. Compared with those previous BQSDC protocols, the advantage of our protocol lies in having the following two characters simultaneously: on one hand, it overcomes the information leakage problem; one the other hand, its capacity is as high as six bits per round communication.