A Quantum Secure Direct Communication Protocol Without Quantum Memories

Lu Yin-Ju

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.

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.

刘丹, 裴昌幸, 权东晓 +1 more

Shang-Jen Su, Shi-Yuan Wang, Matthieu R. Bloch

We develop an information-theoretic analysis of Quantum-Memory-Free (QMF) Quantum Secure Direct Communication (QSDC) under collective attacks as an alternative to the use of a conventional Quantum Key Distribution (QKD) protocol in conjunction with one-time pads. Our main contributions are: 1) a QMF-QSDC protocol that only relies on universal hashing of coded sequences without wiretap coding; 2) a set of privacy amplification theorems for extracting secrecy from coded classical sequences against quantum side-information. These tools open the way to the design of effective QMF-QSDC protocols.

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

Quantum secure direct communication (QSDC) uses the quantum channel to transmit information reliably and securely. 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 a single-photon-memory MDI QSDC protocol (SPMQC) 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 present-day technology.