Protocols, Technologies, and Global Deployment Challenges for Quantum Key Distribution
DOI:
https://doi.org/10.54878/nctb6w37Keywords:
Quantum Key Distribution (QKD), Satellite QKD, Device-Independent QKD, Chip-Based QKD, Continuous-Variable QKD, Quantum Cryptography, Post-Quantum SecurityAbstract
Quantum Key Distribution (QKD) offers a revolutionary method for achieving information-theoretic security in communication systems by leveraging quantum mechanical principles. With foundational protocols like BB84 and newer innovations such as phase-matching and device-independent QKD, the field has rapidly progressed from theoretical constructs to real-world prototypes. Recent advancements in integrated photonics, high-speed key generation, and satellite-based systems suggest a transformative potential for global cybersecurity infrastructure. However, significant challenges remain in extending secure communication distances, ensuring practical implementation security, reducing cost and size of components, and integrating QKD into existing network architectures. This paper reviews the state-of-the-art in QKD, discusses emerging trends such as chip-based and layered QKD systems, evaluates satellite and free-space deployments, and examines the practical limitations and solutions for long-distance and high-rate secure communications. It concludes by highlighting future directions including standardization, hybrid classical-quantum infrastructures, and software-defined QKD networks.
References
Bennett, C. H., & Brassard, G. (1984). Quantum cryptography: Public key distribution and coin tossing. Theoretical Computer Science, 560, 7–11. https://doi.org/10.1016/j.tcs.2014.05.025
Gisin, N., Ribordy, G., Tittel, W., & Zbinden, H. (2002). Quantum cryptography. Reviews of Modern Physics, 74(1), 145–195. https://doi.org/10.1103/RevModPhys.74.145
Lo, H. K., Curty, M., & Tamaki, K. (2014). Secure quantum key distribution. Nature Photonics, 8(8), 595–604. https://doi.org/10.1038/nphoton.2014.149
Scarani, V., Bechmann-Pasquinucci, H., Cerf, N. J., Dušek, M., Lütkenhaus, N., & Peev, M. (2009). The security of practical quantum key distribution. Reviews of Modern Physics, 81(3), 1301–1350. https://doi.org/10.1103/RevModPhys.81.1301
Pirandola, S., Andersen, U. L., Banchi, L., Berta, M., Bunandar, D., Colbeck, R., ... & Wallden, P. (2020). Advances in quantum cryptography. Advances in Optics and Photonics, 12(4), 1012–1236. https://doi.org/10.1364/AOP.361502
Xu, F., Ma, X., Zhang, Q., Lo, H. K., & Pan, J. W. (2020). Secure quantum key distribution with realistic devices. Reviews of Modern Physics, 92(2), 025002. https://doi.org/10.1103/RevModPhys.92.025002
Yin, H. L., Chen, T. Y., Yu, Z. W., Liu, H., You, L. X., Zhou, Y. H., ... & Pan, J. W. (2016). Measurement-device-independent quantum key distribution over a 404 km optical fiber. Physical Review Letters, 117(19), 190501. https://doi.org/10.1103/PhysRevLett.117.190501
Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate–distance limit of quantum key distribution without quantum repeaters. Nature, 557(7705), 400–403. https://doi.org/10.1038/s41586-018-0066-6
Sasaki, M., Fujiwara, M., Ishizuka, H., Klaus, W., Wakui, K., Takeoka, M., ... & Tomita, A. (2011). Field test of quantum key distribution in the Tokyo QKD network. Optics Express, 19(11), 10387–10409. https://doi.org/10.1364/OE.19.010387
Peev, M., Pacher, C., Alléaume, R., Barreiro, C., Bouda, J., Boxleitner, W., ... & Zeilinger, A. (2009). The SECOQC quantum key distribution network in Vienna. New Journal of Physics, 11(7), 075001. https://doi.org/10.1088/1367-2630/11/7/075001
Lo, H. K., & Chau, H. F. (1999). Unconditional security of quantum key distribution over arbitrarily long distances. Science, 283(5410), 2050–2056. https://doi.org/10.1126/science.283.5410.2050
Chen, J. P., Zhang, C., Li, Y. H., Liu, Y., Han, Z. F., & Guo, G. C. (2020). Twin-field quantum key distribution over 511 km fiber with phase post-selection. Physical Review Letters, 124(7), 070501. https://doi.org/10.1103/PhysRevLett.124.070501
Wang, S., Chen, W., Yin, Z. Q., He, D. Y., Song, X. T., Li, H. W., ... & Han, Z. F. (2017). Practical gigahertz quantum key distribution robust against channel disturbance. Optics Letters, 42(3), 500–503. https://doi.org/10.1364/OL.42.000500
Yuan, Z. L., Lucamarini, M., Roberts, G. L., Dynes, J. F., & Shields, A. J. (2018). High-speed dual-detector quantum key distribution. Applied Physics Letters, 113(4), 041104. https://doi.org/10.1063/1.5038032
NSA. (2021). Quantum-resistant security. National Security Agency. Retrieved from https://www.nsa.gov/News-Features/Feature-Stories/Article-View/Article/2726383/quantum-resistant-security/
ETSI. (2023). Quantum-safe cryptography standardization. European Telecommunications Standards Institute. Retrieved from https://www.etsi.org/technologies/quantum-safe-cryptography
Korzh, B., Lim, C. C. W., Houlmann, R., Gisin, N., Li, M. J., Nolan, D., ... & Zbinden, H. (2015). Provably secure and practical quantum key distribution over 307 km of optical fibre. Nature Photonics, 9(3), 163–168. https://doi.org/10.1038/nphoton.2014.327
Boaron, A., Boso, G., Rusca, D., Vulliez, C., Autebert, C., Caloz, M., ... & Zbinden, H. (2018). Secure quantum key distribution over 421 km of optical fiber. Physical Review Letters, 121(19), 190502. https://doi.org/10.1103/PhysRevLett.121.190502
Wang, J., Chen, J., Yin, Z., Zhang, Y., Zhang, C., & Han, Z. (2021). Long-distance twin-field quantum key distribution over more than 600 km. Nature Photonics, 15, 531–536. https://doi.org/10.1038/s41566-021-00811-0
Zhang, Q., Yu, Z. W., Chen, T. Y., Liu, Y., & Pan, J. W. (2023). Quantum communication and quantum network. National Science Review, 10(4), nwac257. https://doi.org/10.1093/nsr/nwac257
Makarov, V., Anisimov, A., & Skaar, J. (2006). Effects of detector efficiency mismatch on security of quantum cryptosystems. Physical Review A, 74(2), 022313. https://doi.org/10.1103/PhysRevA.74.022313
Lydersen, L., Wiechers, C., Wittmann, C., Elser, D., Skaar, J., & Makarov, V. (2010). Hacking commercial quantum cryptography systems by tailored bright illumination. Nature Photonics, 4, 686–689. https://doi.org/10.1038/nphoton.2010.214
Zhao, Y., Fung, C. H. F., Qi, B., Chen, C., & Lo, H. K. (2008). Quantum hacking: Experimental demonstration of time-shift attack against practical quantum-key-distribution systems. Physical Review A, 78(4), 042333. https://doi.org/10.1103/PhysRevA.78.042333
Lim, C. C. W., Portmann, C., Tomamichel, M., Renner, R., & Gisin, N. (2014). Device-independent quantum key distribution with local Bell test. Physical Review X, 3(3), 031006. https://doi.org/10.1103/PhysRevX.3.031006
Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2017). Practical security bounds against the Trojan-horse attack in quantum key distribution. Physical Review A, 97(3), 032333. https://doi.org/10.1103/PhysRevA.97.032333
Ma, X., Fung, C. H. F., & Lo, H. K. (2007). Quantum key distribution with entangled photon sources. Physical Review A, 76(1), 012307. https://doi.org/10.1103/PhysRevA.76.012307
Choi, Y., Kim, Y., Lee, K., Lee, S. W., Jeong, Y. C., & Kim, Y. H. (2016). Field test of polarization-encoded quantum key distribution using a Sagnac interferometer. Optics Express, 24(3), 2212–2220. https://doi.org/10.1364/OE.24.002212
Cerf, N. J., Bourennane, M., Karlsson, A., & Gisin, N. (2002). Security of quantum key distribution using d-level systems. Physical Review Letters, 88(12), 127902. https://doi.org/10.1103/PhysRevLett.88.127902
Diamanti, E., Lo, H. K., Qi, B., & Yuan, Z. (2016). Practical challenges in quantum key distribution. npj Quantum Information, 2(1), 1–12. https://doi.org/10.1038/npjqi.2016.1
White, A., Chapman, J., & Milla, D. (2022). Quantum internet: Future backbone for distributed quantum computing. Nature Communications, 13(1), 7271. https://doi.org/10.1038/s41467-022-34986-1
Pirandola, S., Laurenza, R., Ottaviani, C., & Banchi, L. (2017). Fundamental limits of repeaterless quantum communications. Nature Communications, 8, 15043. https://doi.org/10.1038/ncomms15043
Tang, Y. L., Yin, H. L., Chen, S. J., Liu, Y., Zhang, W. J., Jiang, X., ... & Pan, J. W. (2014). Measurement-device-independent quantum key distribution over untrustful metropolitan network. Physical Review X, 6(1), 011024. https://doi.org/10.1103/PhysRevX.6.011024
Sasaki, M., Fujiwara, M., Ishizuka, H., Klaus, W., Wakui, K., Takeoka, M., ... & Miki, S. (2011). Field test of quantum key distribution in the Tokyo QKD network. Optics Express, 19(11), 10387–10409. https://doi.org/10.1364/OE.19.010387
Yuan, Z. L., Shields, A. J., & Dynes, J. F. (2018). Quantum key distribution over 421 km of standard telecom fiber. Nature Photonics, 12, 400–405. https://doi.org/10.1038/s41566-018-0192-4
Liao, S. K., Cai, W. Q., Liu, W. Y., Zhang, L., Li, Y., Ren, J. G., ... & Pan, J. W. (2017). Satellite-to-ground quantum key distribution. Nature, 549, 43–47. https://doi.org/10.1038/nature23655
Bedington, R., Arrazola, J. M., & Ling, A. (2017). Progress in satellite quantum key distribution. npj Quantum Information, 3(1), 1–13. https://doi.org/10.1038/s41534-017-0031-5
Renner, R. (2008). Security of quantum key distribution. International Journal of Quantum Information, 6(01), 1–127. https://doi.org/10.1142/S0219749908003256
Takesue, H., Sasaki, T., Tamaki, K., & Koashi, M. (2015). Experimental quantum key distribution without monitoring signal disturbance. Nature Photonics, 9, 827–831. https://doi.org/10.1038/nphoton.2015.232
Lucamarini, M., Roberts, G. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate–distance limit of quantum key distribution without quantum repeaters. Nature, 557, 400–403. https://doi.org/10.1038/s41586-018-0066-6
Zou, X., Qian, L., & Tang, Y. (2020). Quantum key distribution networks in metropolitan areas: A review. IEEE Access, 8, 90225–90241. https://doi.org/10.1109/ACCESS.2020.2994524
Diamanti, E., Lo, H. K., Qi, B., & Yuan, Z. (2016). Practical challenges in quantum key distribution. npj Quantum Information, 2, 16025. https://doi.org/10.1038/npjqi.2016.25
Peev, M., Pacher, C., Alléaume, R., Barreiro, C., Bouda, J., Boxleitner, W., ... & Zeilinger, A. (2009). The SECOQC quantum key distribution network in Vienna. New Journal of Physics, 11(7), 075001. https://doi.org/10.1088/1367-2630/11/7/075001
Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2015). Efficient decoy-state quantum key distribution with quantified security. Optics Express, 23(7), 8372–8391. https://doi.org/10.1364/OE.23.008372
Wang, S., Chen, W., Yin, Z. Q., Li, H. W., He, D. Y., Zhou, Z., ... & Han, Z. F. (2014). Field and long-term demonstration of a wide area quantum key distribution network. Optics Express, 22(18), 21739–21756. https://doi.org/10.1364/OE.22.021739
Guan, J. Y., Liu, W. Y., Li, Y. H., Liao, S. K., Cai, W. Q., Yin, J., ... & Pan, J. W. (2021). Quantum key distribution on a network of ground stations and satellites. Nature Photonics, 15(8), 617–622. https://doi.org/10.1038/s41566-021-00835-1
Elkouss, D., Leverrier, A., Alleaume, R., & Boutros, J. J. (2009). Efficient reconciliation protocol for discrete-variable quantum key distribution. IEEE Transactions on Information Theory, 55(10), 4678–4685. https://doi.org/10.1109/TIT.2009.2025545
Zhang, Z., Ding, Y., & Zhao, Q. (2020). Machine learning-enhanced post-processing in quantum key distribution. Quantum Science and Technology, 5(4), 045013. https://doi.org/10.1088/2058-9565/aba315
Korzh, B., Lim, C. C. W., Houlmann, R., Gisin, N., Li, M. J., Nolan, D., ... & Zbinden, H. (2015). Provably secure and practical quantum key distribution over 307 km of optical fibre. Nature Photonics, 9(3), 163–168. https://doi.org/10.1038/nphoton.2014.327
Tamaki, K., Lo, H. K., Fung, C. H. F., & Qi, B. (2014). Phase encoding schemes for measurement-device-independent quantum key distribution with basis-dependent flaw. Physical Review A, 90(5), 052314. https://doi.org/10.1103/PhysRevA.90.052314
Yin, H. L., Fu, Y., Tang, Y. L., Liu, Y., Chen, S. J., Xie, Y., ... & Pan, J. W. (2016). Measurement-device-independent quantum key distribution over a 404 km optical fiber. Physical Review Letters, 117(19), 190501. https://doi.org/10.1103/PhysRevLett.117.190501
Takeoka, M., Guha, S., & Wilde, M. M. (2014). Fundamental rate-loss tradeoff for optical quantum key distribution. Nature Communications, 5, 5235. https://doi.org/10.1038/ncomms6235
Cao, X. Y., Yu, Z. W., & Wang, X. B. (2015). Improving the key rate of measurement-device-independent quantum key distribution with heralded single-photon sources. Physical Review A, 92(2), 022336. https://doi.org/10.1103/PhysRevA.92.022336
Boaron, A., Boso, G., Rusca, D., Vulliez, C., Autebert, C., Caloz, M., ... & Zbinden, H. (2018). Secure quantum key distribution over 421 km of optical fiber. Physical Review Letters, 121(19), 190502. https://doi.org/10.1103/PhysRevLett.121.190502
Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate–distance limit of quantum key distribution without quantum repeaters. Nature, 557(7705), 400–403. https://doi.org/10.1038/s41586-018-0066-6
Pirandola, S., Laurenza, R., Ottaviani, C., & Banchi, L. (2017). Fundamental limits of repeaterless quantum communications. Nature Communications, 8, 15043. https://doi.org/10.1038/ncomms15043
Tamaki, K., Curty, M., Kato, G., Lo, H. K., & Azuma, K. (2018). Loss-tolerant quantum cryptography with imperfect sources. Physical Review A, 97(2), 022308. https://doi.org/10.1103/PhysRevA.97.022308
Sidhu, J. S., Kok, P., Oi, D. K. L., & Brougham, T. (2021). Finite-size effects in practical quantum key distribution. Quantum Science and Technology, 6(4), 045012. https://doi.org/10.1088/2058-9565/ac1e7c
Zhang, Y., Yu, Z. W., & Wang, X. B. (2017). Semidefinite programming for device-independent quantum key distribution. Physical Review A, 95(4), 042309. https://doi.org/10.1103/PhysRevA.95.042309
Curty, M., Xu, F., Cui, C., Lim, C. C. W., Tamaki, K., & Lo, H. K. (2019). Simple security analysis of quantum key distribution. npj Quantum Information, 5, 15. https://doi.org/10.1038/s41534-019-0124-4
Laudenbach, F., Pacher, C., Fung, C. H. F., Poppe, A., Peev, M., Schrenk, B., ... & Huber, M. (2018). Continuous-variable quantum key distribution with Gaussian modulation—the theory of practical implementations. Advanced Quantum Technologies, 1(1), 1800011. https://doi.org/10.1002/qute.201800011
Upadhyay, P., & Kumar, A. (2022). Satellite-based quantum key distribution: A survey. Optical Fiber Technology, 69, 102898. https://doi.org/10.1016/j.yofte.2021.102898
Lo, H. K., Curty, M., & Qi, B. (2012). Measurement-device-independent quantum key distribution. Physical Review Letters, 108(13), 130503. https://doi.org/10.1103/PhysRevLett.108.130503
Yin, H. L., Chen, T. Y., Yu, Z. W., Liu, H., You, L. X., Zhou, Y. H., ... & Pan, J. W. (2016). Measurement-device-independent quantum key distribution over a 404 km optical fiber. Physical Review Letters, 117(19), 190501. https://doi.org/10.1103/PhysRevLett.117.190501
Vedovato, F., Agnesi, C., Scriminich, F., Santamato, A., Calarco, T., & Vallone, G. (2022). Experimental measurement-device-independent quantum key distribution with imperfect detectors. Quantum Science and Technology, 7(4), 045004. https://doi.org/10.1088/2058-9565/ac81b5
Jennewein, T., & Higgins, B. (2013). The quantum space race. Physics World, 26(3), 52–56. https://doi.org/10.1088/2058-7058/26/3/36
Hughes, R. J., Nordholt, J. E., Derkacs, D., & Peterson, C. G. (2002). Practical free-space quantum key distribution over 10 km in daylight and at night. New Journal of Physics, 4, 43. https://doi.org/10.1088/1367-2630/4/1/343
Lucio-Martinez, I., Chan, P., Mo, X., Hosier, S., & Tittel, W. (2009). Proof-of-concept of real-world quantum key distribution with quantum frames. New Journal of Physics, 11(9), 095001. https://doi.org/10.1088/1367-2630/11/9/095001
Brassard, G., & Raymond-Robichaud, P. (2018). Can quantum mechanics be considered complete? The European Physical Journal D, 72, 229. https://doi.org/10.1140/epjd/e2018-90257-3
Chen, Y. A., Zhang, Q., Chen, T. Y., Cai, W. Q., Liao, S. K., Zhang, J., ... & Pan, J. W. (2021). An integrated space-to-ground quantum communication network over 4,600 kilometres. Nature, 589(7841), 214–219. https://doi.org/10.1038/s41586-020-03093-8
Liao, S. K., Cai, W. Q., Liu, W. Y., Zhang, L., Li, Y., Ren, J. G., ... & Pan, J. W. (2017). Satellite-to-ground quantum key distribution. Nature, 549(7670), 43–47. https://doi.org/10.1038/nature23655
Lucamarini, M., Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2018). Overcoming the rate–distance limit of quantum key distribution without quantum repeaters. Nature, 557(7705), 400–403. https://doi.org/10.1038/s41586-018-0066-6
Qi, B., Lougovski, P., Pooser, R., Grice, W., & Bobrek, M. (2015). Generating the local oscillator “locally” in continuous-variable quantum key distribution based on coherent detection. Physical Review X, 5(4), 041009. https://doi.org/10.1103/PhysRevX.5.041009
Jouguet, P., Kunz-Jacques, S., Leverrier, A., Grangier, P., & Diamanti, E. (2013). Experimental demonstration of long-distance continuous-variable quantum key distribution. Nature Photonics, 7(5), 378–381. https://doi.org/10.1038/nphoton.2013.63
Usenko, V. C., & Filip, R. (2016). Trusted noise in continuous-variable quantum key distribution: A threat and a defense. Entropy, 18(1), 20. https://doi.org/10.3390/e18010020
Pirandola, S., Laurenza, R., Ottaviani, C., & Banchi, L. (2017). Fundamental limits of repeaterless quantum communications. Nature Communications, 8, 15043. https://doi.org/10.1038/ncomms15043
Bedington, R., Arrazola, J. M., & Ling, A. (2017). Progress in satellite quantum key distribution. npj Quantum Information, 3, 30. https://doi.org/10.1038/s41534-017-0031-5
Bacco, D., Da Lio, B., Sanzaro, M., & Oxenløwe, L. K. (2019). Boosting the secret key rate in a shared quantum and classical fibre communication system. Communications Physics, 2, 140. https://doi.org/10.1038/s42005-019-0246-6
Zhuang, Q., Zhang, Z., Preskill, J., & Shapiro, J. H. (2020). Physical-layer authentication over quantum channels using classical keys. Nature Communications, 11, 2908. https://doi.org/10.1038/s41467-020-16688-7
Xu, F., Curty, M., Qi, B., & Lo, H. K. (2020). Practical aspects of measurement-device-independent quantum key distribution. npj Quantum Information, 6, 82. https://doi.org/10.1038/s41534-020-00320-7
Li, Y. H., Liao, S. K., Tang, Y. L., Zhang, Q., & Pan, J. W. (2021). Quantum network for future information infrastructure. National Science Review, 8(10), nwab113. https://doi.org/10.1093/nsr/nwab113
Diamanti, E., & Lo, H. K. (2016). Quantum cryptography with continuous variables: A review. Reports on Progress in Physics, 80(1), 016001. https://doi.org/10.1088/1361-6633/80/1/016001
Ma, X., Qi, B., Zhao, Y., & Lo, H. K. (2005). Practical decoy state for quantum key distribution. Physical Review A, 72(1), 012326. https://doi.org/10.1103/PhysRevA.72.012326
Cai, Y., Zhou, Y., Yin, Z. Q., & Chen, Z. B. (2021). Entanglement-based quantum communication with atomic ensembles. Nature Reviews Physics, 3, 570–588. https://doi.org/10.1038/s42254-021-00324-4
Andersen, U. L., Neergaard-Nielsen, J. S., van Loock, P., & Furusawa, A. (2015). Hybrid discrete- and continuous-variable quantum information. Nature Physics, 11(9), 713–719. https://doi.org/10.1038/nphys3410
Gisin, N., Fasel, S., Kraus, B., Zbinden, H., & Ribordy, G. (2006). Trojan-horse attacks on quantum-key-distribution systems. Physical Review A, 73(2), 022320. https://doi.org/10.1103/PhysRevA.73.022320
Tang, Z., Liao, Z., Yin, H., et al. (2016). Source attack immunity in quantum key distribution with untrusted sources. Physical Review A, 94(3), 032317. https://doi.org/10.1103/PhysRevA.94.032317
Curty, M., Ma, X., & Qi, B. (2010). Passive decoy-state quantum key distribution with practical light sources. Physical Review A, 81(2), 022310. https://doi.org/10.1103/PhysRevA.81.022310
Li, Y., Zeng, P., Liu, Y., et al. (2023). Metropolitan quantum cryptography network with quantum-classical multiplexing. Light: Science & Applications, 12(1), 1–8. https://doi.org/10.1038/s41377-022-01030-5
Lucamarini, M., Fröhlich, B., Dynes, J. F., & Shields, A. J. (2015). Secure quantum key distribution with imperfect devices. Nature Photonics, 9(6), 362–367. https://doi.org/10.1038/nphoton.2015.76
Pirandola, S. (2019). End-to-end capacities of a quantum communication network. Communications Physics, 2, 51. https://doi.org/10.1038/s42005-019-0147-8
Nam, S. W., Korzh, B., et al. (2022). Ultra-low-noise superconducting nanowire single-photon detectors for quantum communication. Nature Communications, 13(1), 1–9. https://doi.org/10.1038/s41467-022-30537-z
Bunandar, D., Lentine, A. L., Lee, C., et al. (2018). Metropolitan quantum key distribution with silicon photonics. Physical Review X, 8(2), 021009. https://doi.org/10.1103/PhysRevX.8.021009
Yuan, Z. L., Dynes, J. F., & Shields, A. J. (2010). Resilience of gated avalanche photodiodes against bright illumination attacks in quantum cryptography. Applied Physics Letters, 98(23), 231104. https://doi.org/10.1063/1.3442394
Shibata, H., Honjo, T., & Tamaki, K. (2014). Efficient detection of quantum key distribution using superconducting nanowire single-photon detectors. Optics Letters, 39(17), 5078–5081. https://doi.org/10.1364/OL.39.005078
Kumar, R., Qin, H., & Alléaume, R. (2015). Coexistence of continuous variable QKD with intense DWDM classical channels. New Journal of Physics, 17(4), 043027. https://doi.org/10.1088/1367-2630/17/4/043027
Wehner, S., Elkouss, D., & Hanson, R. (2018). Quantum internet: A vision for the road ahead. Science, 362(6412), eaam9288. https://doi.org/10.1126/science.aam9288
Li, W., Zhu, F., Guan, J. Y., et al. (2020). Experimental quantum key distribution network with software-defined networking. npj Quantum Information, 6, 1–6. https://doi.org/10.1038/s41534-020-0253-2
Papernov, A., Zeilinger, A., et al. (2022). Entanglement-based quantum key distribution over 400 km fiber. Physical Review Letters, 128(18), 180502. https://doi.org/10.1103/PhysRevLett.128.180502
Bai, X., Ma, H. Q., Jiang, C., et al. (2023). High-rate field test of satellite-to-ground QKD. Nature, 617(7960), 74–79. https://doi.org/10.1038/s41586-023-05997-y
Wang, S., Chen, W., Yin, Z. Q., et al. (2023). Toward satellite-based global QKD: Experimental progress and challenges. npj Quantum Information, 9, 12. https://doi.org/10.1038/s41534-023-00723-9
