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Finite-key effects in multipartite quantum key distribution protocols
摘要： We analyze the security of two multipartite quantum key distribution (QKD) protocols, specifically we introduce an N-partite version of the BB84 protocol and we discuss the N-partite six-state protocol proposed by Epping et al (2017 New J. Phys. 19 093012). The security analysis proceeds from the generalization of known results in bipartite QKD to the multipartite scenario, and takes into account finite resources. In this context we derive a computable expression for the achievable key rate of both protocols by employing the best-known strategies: the uncertainty relation and the postselection technique. We compare the performances of the two protocols both for finite resources and infinitely many signals.
关键词： finite resources,conference key agreement,quantum key distribution,uncertainty relation for smooth entropies,finite-key effects,security analysis,multipartite qkd
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Field Trial of a Finite-Key Quantum Key Distribution System in the Metropolitan Florence Area
摘要： In a society based on the continuous exchange of sensitive data and information, the importance of secure and trustful communications is essential. Quantum key distribution (QKD) makes it possible to share data in an unconditionally secure way exploiting the basic principles of Quantum Mechanics [1]. During the last 30 years, many QKD protocols have been developed and tested, achieving long distance transmission [2] and secret key rates up to hundreds of Mbits per second [3]. However, this technology is still far from a large-scale deployment in existing fiber networks and telecom infrastructures, due to multiple factors: low secret-key rate, limited distance between users, lack of applications, high costs and high requirements in terms of low noise fiber links. In order to reveal practical issues in real-world deployments, quantum field trials have been implemented by exploiting installed fiber links on a metropolitan scale. While many of these experiments were performed on a dark fiber (thus requiring a dedicated link for quantum key transmission only), other field trials explored the coexistence between weak coherent pulses and classical signals propagating through the same fiber [4-7], see Figure 1 a). In this work we report a low-cost field trial demonstration of a complete QKD system working in the C-band telecom wavelength, performed over an installed fiber situated in Florence. A time-bin three-stateprotocol with one-decoy state method is implemented in the experiment [2]. As illustrated in Figure 1 b), theexperimental setup consists of a transmitter (Alice), working at ch 21 of 100GHz DWDM grid, and a receiver(Bob) connected by a metropolitan dark-fiber link in a loop-back configuration. The total distance covered in thefiber link is about 40 km, with an overall transmission loss of 21 dB. Secure key generation of 3.4 kbps (in thefinite key scenario) is achieved, with simultaneous transmission of a classical synchronization signal, at adifferent wavelength (ch 51 of 100GHz DWDM grid with -29 dBm input power), through the same fiber. InFigure 1 c) we report the secret key rate and the bit error rate, measured for several hours to prove the stability ofthe apparatus.
关键词： metropolitan network,QKD,finite-key analysis,Quantum key distribution,field trial
更新于2025-09-16 10:30:52
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Finite-key analysis for high-dimensional quantum key distribution with intensity fluctuations
摘要： High-dimensional quantum key distribution (HD-QKD) can increase the photon information efficiency and be robust to noise. Several HD-QKD experiments have been demonstrated to verify above appealing features. However, device imperfections, which have great impacts on the security of HD-QKD system, have not been widely discussed. In this paper, we mainly investigate the finite-key analysis against coherent attacks for HD-QKD without and with intensity fluctuations. For the case without intensity fluctuations, we present the parameter estimation based on the Chernoff bound and the improved Chernoff bound. When considering the case with intensity fluctuations, we present the finite-key analysis based on Azuma’s inequality. By numerical simulations, we find that the performance of HD-QKD for the finite-key scenario based on the improved Chernoff bound is tighter than those based on the Chernoff bound or Hoeffding’s inequality in terms of the secret-key rate and the maximum transmission distance. Moreover, we find that intensity fluctuations affect the performance of HD-QKD greatly and the effect for short running time of transmission is more obvious.
关键词： Quantum key distribution,Finite-key,Intensity fluctuations
更新于2025-09-10 09:29:36