ZHANG Feihao;LONG Guilu;

• 1:Beijing Academy of Quantum Information Sciences
• 2:Department of Physics
• 3:Tsinghua University

Abstract：

Quantum secure direct communication is a quantum communication technology that uses quantum states as carriers to transmit information securely and directly,first proposed by a team at Tsinghua University in 2000.Quantum communication broadly refers to information transfer processing tasks accomplished through the transmission of quantum states,which can be categorized into three types based on the content transmitted:quantum key distribution for transmitting random numbers,quantum secure direct communication for transmitting classical information, and quantum teleportation for transmitting quantum information.After more than two decades of development,quantum secure direct communication has matured and entered practical application:a theoretical framework tailored for scenarios with high loss,high noise,and stringent security requirements has been established;experimental demonstrations of quantum direct communication in optical fibers and free space havebeencompleted;three milestone systems for quantum secure direct communication at the metropolitan,intercity,and network levels have been built;and successful trials have been conducted in various scenarios such as 5 Gprivate networks and banking applications.Quantum secure direct communication offers multiple applications:it prevents information leakage by detecting eavesdropping,ensuring information security;identifies exposed locations by monitoring surveillance activities,providing technical support for preventing targeted eliminations and safeguarding commanders' personal safety;and detects intrusion and tampering behaviors,offering novel protection for cybersecurity.Currently,quantum direct communication has been incorporated into relevant planning documents in China,the European Union,and the United States,and is undergoing rapid development.This article briefly outlines the historical development,fundamental principles,research advancements,and future prospects of quantum direct communication.

Key Words： quantum secure direct communication;quantum direct communication;quantum communication

Abstract:

Keywords:

Foundation: 国家自然科学基金（编号：62471046）资助项目

Authors: ZHANG Feihao;LONG Guilu;

DOI: 10.27024/j.wlygc.2026.06.03.is

References：

• [1] LONG G L,LIU X S.Theoretically efficient high-capacity quantum-key-distribution scheme[J/OL].arXiv,2000,arXiv:quant-ph/0012056.https://arxiv.org/abs/quant-ph/0012056;also as Physical Review A,2002,65(3):032302.
• [2] DENG F G,LONG G L,LIU X S.Two-step quantum direct communication protocol using the Einstein-Podolsky-Rosen pair block[J].Physical Review A,2003,68:042317.
• [3] DENG F G,LONG G L.Repeatable classical one-time-pad crypto-system with quantum mechanics[J/OL].arXiv,2019,arXiv:1902.04218.https://arxiv.org/abs/1902.04218
• [4] WEN K,DENG F G,LONG G L.Reusable vernam cipher with quantum media[J/OL].arXiv,2007,arXiv:0711.1632.https://arxiv.org/abs/0711.1632
• [5] BENNETT C H,BRASSARD G,BREIDBART S.Quantum cryptography II:How to re-use a one-time padsafely even if P=NP[J].Natural Computing,2014,13(4):453-458.
• [6] LUM D J,HOWELL J C,ALLMAN M S,et al.Quantum enigma machine:Experimentally demonstrating quantum data locking[J].Physical Review A,2016,94(2):022315.
• [7] DENG F G,LONG G L.Secure direct communication with a quantum one-time pad[J].Physical Review A,2004,69(5):052319.
• [8] WANG C,DENG F G,LI Y S,et al.Quantum secure direct communication with high-dimension quantum superdense coding[J].Physical Review A,2005,71(4):044305.
• [9] LYU X,MA Z,FENG D G.Secure Direct Communication Using Quantum Calderbank-Shor-Steane Codes[J/OL].IACR Cryptol.ePrint Arch,2004,2004:229.
• [10] GAO T,YAN F L,WANG Z X.Deterministic secure direct communication using GHZ states and swapping quantum entanglement[J].Journal of Physics A:Mathematical and General,2005,38(25):5761-5770.
• [11] SHI J,GONG Y X,XU P,et al.Quantum secure direct communication by using three-dimensional hyperentanglement[J].Communications in Theoretical Physics,2011,56(5):831-836.
• [12] QI R Y,SUN Z,LIN Z S,et al.Implementation and security analysis of practical quantum secure direct communication[J].Light:Science & Applications,2019,8(1):22.
• [13] WU J,LONG G L,HAYASHI M.Quantum Secure Direct Communication with Private Dense Coding Using a General Preshared Quantum State[J].Physical Review Applied,2022,17(6):064011.
• [14] ZHOU Z,SHENG Y,NIU P,et al.Measurement-device-independent quantum secure direct communication[J].Sci.China Phys.Mech.Astron.,2020,63:230362.
• [15] ZHOU L,SHENG Y B,LONG G L.Device-independent quantum secure direct communication against collective attacks[J].Science Bulletin,2020,65(1):12-20.
• [16] HU J Y,YU B,JING M Y,et al.Experimental quantum secure direct communication with single photons[J].Light:Science & Applications,2016,5(9):e16144-e16144.
• [17] ZHANG W,DING D S,SHENG Y B,et al.Quantum secure direct communication with quantum memory[J].Physical Review Letters,2017,118(22):220501.
• [18] ZHU F,ZHANG W,SHENG Y,et al.Experimental long-distance quantum secure direct communication[J].Science Bulletin,2017,62(22):1519-1524.
• [19] LONG G L,ZHANG H.Drastic increase of channel capacity in quantum secure direct communication using masking[J].Science Bulletin,2021,66(13):1267-1269.
• [20] CAO Z W,LU Y,CHAI G,et al.Realization of Quantum Secure Direct Communication with Continuous Variable[J].Research,2023,6:0193.
• [21] PAPARELLE I,MOUSAVI F,SCAZZA F,et al.Experimental direct quantum communication with squeezed states[J].Optics Express,2025,33(14):28917-28934.
• [22] PAN D,LIU Y C,NIU P,et al.Simultaneous transmission of information and key exchange using the same photonic quantum states[J].Science Advances,2025,11(8):eadt4627.
• [23] QI Z,LI Y,HUANG Y,et al.A 15-user quantum secure direct communication network[J].Light:Science & Applications,2021,10(1):183.
• [24] LONG G L,PAN D,SHENG Y B,et al.An Evolutionary Pathway for the Quantum Internet Relying on Secure Classical Repeaters[J].IEEE Network,2022,36(3):82-88.
• [25] 吴永飞，龙桂鲁，伊亮，等.量子直接通信在银行业务中的应用[J].银行家，2022,(6):72-74.WU Y F,LONG G L,YI L,et al.Application of Quantum Direct Communication in Banking[J].The Chinese Banker,2022,(6):72-74.(in Chinese)
• [26] SHAPIRO J H,BOROSON D M,DIXON P B,et al.Quantum low probability of intercept[J].Journal of the Optical Society of America B,2019,36(3):B41-B50.
• [27] VAZQUEZ-CASTRO A,RUSCA D,ZBINDEN H.Quantum keyless private communication versus quantum key distribution for space links[J].Physical Review Applied,2021,16(1):014006.
• [28] MENDES P N,TEIXEIRA G L,PINHO D,et al.Optical payload design for downlink quantum key distribution and keyless communication using CubeSats[J].EPJ Quantum Technology,2024,11(1):48.
• [29] MENDES P N,RUSCA D,ZBINDEN H,et al.Quantum Keyless Private Communication under intense background noise[J/OL].arXiv,2025,arXiv:2505.07940.https://arxiv.org/abs/2505.07940
• [30] KANIA E B,COSTELLO J K.Quantum hegemony:China's ambitions and the challenge to US innovation leadership[M].Washington,D.C.:Center for New American Security,2018.
• [31] SRIA 2030:Roadmap and Quantum Ambitions over this Decade[EB/OL].(2024-01-14).https://qt.eu/media/pdf/Strategic-Research-and-Industry-Agenda-2030.pdf
• [32] QuANET:Quantum-Augmented Network[EB/OL].(2023-06-13).https://www.darpa.mil/research/programs/quantum-augmented-network.