A Novel Practical Quantum Secure Direct Communication Protocol

Zhen Sun, Ruoyang Qi, Zaisheng Lin +3 more

The extensive studies on the quantum communication, which provides a novel means of secure communication, have been carried out in last decades. Among the various types of quantum communication, quantum secure direct communication (QSDC) can securely transmit message directly through a quantum channel. This paper reports a practical scheme of QSDC without quantum memory, taking advantage of the wiretap channel theory and classical coding theory. The proposed approach solves one of the biggest obstacle of practical applications of QSDC, the quantum memory, which is indispensable in original QSDC protocols. The design and detailed scheme for implementation of the proposed protocol are given.

Yunyan Yang

Xiangjie Li, Dong Pan, Gui‐Lu Long +1 more

In Part I of this two-part letter on single-photon-memory measurement-device-independent quantum secure direct communication (SPMQC), we reviewed the fundamentals and evolution of quantum secure direct communication (QSDC). In this Part II, we propose a practical protocol and analyze its secrecy capacity. In order to eliminate the security loopholes resulting from practical detectors, the measurement-device-independent (MDI) QSDC protocol has been proposed. However, block-based transmission of quantum states is utilized in MDI-QSDC, which requires practical quantum memory that is still unavailable at the time of writing. For circumventing this impediment, we propose the SPMQC protocol for dispensing with high-performance quantum memory. The performance of the proposed protocol is characterized by simulations considering realistic experimental parameters, and the results show that it is feasible to implement SPMQC by relying on existing technology.

刘丹, 裴昌幸, 权东晓 +1 more

Siddharth Patwardhan, Subhayan Roy Moulick, Prasanta K. Panigrahi

Qi Zhang, Ming‐Ming Du, Wei Zhong +2 more

Abstract Multipartite quantum secure direct communication (MQSDC) enables multiple message senders to simultaneously and independently transmit secret messages to a message receiver through quantum channels without sharing keys. Existing MQSDC protocols all assume that all the communication parties are legal, which is difficult to guarantee in practical applications. In this study, a single‐photon based three‐party QSDC protocol with identity authentication is proposed. In the protocol, the message receiver first authenticates the identity of two practical message senders. Only when the identity authentication is passed, the legal message senders can encode their messages by the hyper‐encoding technology. In theory, two bits of messages can be transmitted to the message receiver in a communication round. The protocol can resist the external attack and internal attack, and guarantee the security of the transmitted messages and the identity codes of each legal message sender. The secret message capacity of the protocol is simulated with two‐decoy‐state method. The maximal communication distance between any two communication parties can reach 31.75 km with weak signal and decoy state pulses. The three‐party QSDC protocol can be extended to a general MQSDC protocol and has important application in the further practical MQSDC field.