Long-distance quantum key distribution secure against coherent attacks

Fröhlich, B.; Lucamarini, Marco; Dynes, J. F.; Comandar, Lucian C.; Tam, Winci; Plews, Alan; Sharpe, A. W.; Yuan, Zhiliang; Shields, A. J.

doi:10.1364/optica.4.000163

Cited by 163 publications

(98 citation statements)

References 68 publications

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“…Although, in general, Alice can use an arbitrary number of intensity settings to prepare her decoy states in the protocol, for simplicity and without loss of generality, in this work we shall consider, just as an example, a threeintensity decoy-state BB84 protocol with a biased basis choice [17,18], which is the most implemented solution for long-distance QKD experiments [19][20][21][22][23][24][25]. In addition, we shall assume that Alice and Bob distill a secret key only from those events where both of them select the Z basis and Alice selects the signal intensity, which typically corresponds to the largest intensity.…”

Section: Assumptions and Decoy-state Bb84 Protocolmentioning

confidence: 99%

“…where N χ denotes the number of events where Alice sends a pulse in the χ basis and Bob measures it also in the χ basis, we obtain represents the conditional expected number of events where Alice selects the intensity γ j and sends Bob an n-photon pulse, and Bob's detectors click given that both Alice and Bob select the χ basis. We will denote it by  g c | n click, , j and, with this notation, equation (24) has the following form: If we consider the case where l=k, then equation (25) can be rewritten as follows:…”

Section: C1 Asymptotic Limitmentioning

confidence: 99%

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Finite-key security analysis for quantum key distribution with leaky sources

2018

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Security proofs of quantum key distribution (QKD) typically assume that the devices of the legitimate users are perfectly shielded from the eavesdropper. This assumption is, however, very hard to meet in practice, and thus the security of current QKD implementations is not guaranteed. Here, we fill this gap by providing a finite-key security analysis for QKD which is valid against arbitrary information leakage from the state preparation process of the legitimate users. For this, we extend the techniques introduced by Tamaki et al (2016 New J. Phys. 18 065008) to the finite-key regime, and we evaluate the security of a leaky decoy-state BB84 protocol with biased basis choice, which is one of the most implemented QKD schemes today. Our simulation results demonstrate the practicability of QKD over long distances and within a reasonable time frame given that the legitimate users' devices are sufficiently isolated.While the results in [1,7] constitute an important step toward guaranteeing the security of quantum communication systems in the presence of information leakage, both analyses consider the asymptotic scenario where Alice sends Bob an infinite number of light pulses. This means that these results cannot be directly applied to real-life QKD implementations, where Alice sends Bob only a finite number of signals and they distill finitelength keys [12][13][14][15][16]. In this work, we fill this gap and extend the general framework introduced in [1] to the finite-key scenario. For this, we present a finite-key parameter estimation method which can be applied in the presence of information leakage. In particular, and for concreteness, we consider a biased basis choice decoystate QKD protocol [17,18] with three-intensity settings. This is one of the most implemented QKD schemes today [19][20][21][22][23][24][25]. Note, however, that our results could be straightforwardly adapted as well to analyze the security of other decoy-state based QKD systems.In addition, we shall consider information leakage from both the IM and the PM of Alice's transmitter. The former implies that a key assumption of the decoy-state method is violated, as now the yield of an n-photon signal could depend on the intensity setting used by Alice to generate it. As a result, the security analysis cannot be based on the typical counterfactual scenario where the intensity setting for each transmitted signal is selected by Alice a posteriori, that is, after Bob has already detected all the incoming signals. To solve this problem, we use the trace distance argument introduced in [1], which relates the n-photon yields (as well as the error rates) associated to pulses generated with different intensity settings, in combination with Azuma's inequality [26]. This inequality allows us to tackle statistical fluctuations in a finite-key regime while guaranteeing security against general attacks. To include the effect of information leakage from the PM in the security analysis, we apply the quantum coin idea introduced in [27, 28] to the finite-key regime....

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Section: Assumptions and Decoy-state Bb84 Protocolmentioning

confidence: 99%

Section: C1 Asymptotic Limitmentioning

confidence: 99%

Finite-key security analysis for quantum key distribution with leaky sources

2018

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“…Practically, any eavesdropper (i.e., commonly known as Eve) attempting to acquire information between Alice and Bob will disturb the quantum state of the encrypted data and thus can be detected by the bona fide users according to the noncloning theorem [8] by monitoring the disturbance in terms of quantum bit-error ratio (QBER) or excess noise. The quest for long distance and high bit-rate quantum encrypted transmission using optical fibers [9] has led researchers to investigate a range of methods [10,11]. Two standard techniques have been implemented for encrypted transmission over standard single mode fiber (SSMF), that is, DV-QKD [12,13] and CV-QKD [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Quantum-to-the-Home: Achieving Gbits/s Secure Key Rates via Commercial Off-the-Shelf Telecommunication Equipment

Asif

Buchanan

2017

Security and Communication Networks

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There is current significant interest in Fiber-to-the-Home (FTTH) networks, that is, end-to-end optical connectivity. Currently, it may be limited due to the presence of last-mile copper wire connections. However, in near future, it is envisaged that FTTH connections will exist, and a key offering would be the possibility of optical encryption that can best be implemented using Quantum Key Distribution (QKD). However, it is very important that the QKD infrastructure is compatible with the already existing networks for a smooth transition and integration with the classical data traffic. In this paper, we report the feasibility of using off-the-shelf telecommunication components to enable high performance Continuous Variable-Quantum Key Distribution (CV-QKD) systems that can yield secure key rates in the range of 100 Mbits/s under practical operating conditions. Multilevel phase modulated signals ( -PSK) are evaluated in terms of secure key rates and transmission distances. The traditional receiver is discussed, aided by the phase noise cancellation based digital signal processing module for detecting the complex quantum signals. Furthermore, we have discussed the compatibility of multiplexers and demultiplexers for wavelength division multiplexed Quantum-to-the-Home (QTTH) network and the impact of splitting ratio is analyzed. The results are thoroughly compared with the commercially available high-cost encryption modules.

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“…In such scheme, the spontaneous Raman scattering (SRS) noise generated by classical optical signals is the dominant impairment for quantum signals [6]. The SRS noise can be suppressed by three major techniques including simultaneous filtering in the time and frequency domains [7], increasing the spectral interval between quantum and classical signals [8], and decreasing the launched power of classical optical communication [9].…”

Section: Introductionmentioning

confidence: 99%

Long-distance transmission of quantum key distribution coexisting with classical optical communication over a weakly-coupled few-mode fiber

Wang¹,

Mao²,

Shen³

et al. 2020

Opt. Express

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Quantum key distribution (QKD) is one of the most practical applications in quantum information processing, which can generate information-theoretical secure keys between remote parties. With the help of the wavelengthdivision multiplexing technique, QKD has been integrated with the classical optical communication networks. The wavelength-division multiplexing can be further improved by the mode-wavelength dual multiplexing technique with few-mode fiber (FMF), which has additional modal isolation and large effective core area of mode, and particularly is practical in fabrication and splicing technology compared with the multi-core fiber. Here, we present for the first time a QKD implementation coexisting with classical optical communication over weakly-coupled FMF using all-fiber mode-selective couplers. The co-propagation of QKD with one 100 Gbps classical data channel at -2.60 dBm launched power is achieved over 86 km FMF with 1.3 kbps real-time secure key generation. Compared with single-mode fiber, the average Raman noise in FMF is reduced by 86% at the same fiber-input power. Our work implements an important approach to the integration between QKD and classical optical communication and previews the compatibility of quantum communications with the next-generation mode division multiplexing networks.

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Long-distance quantum key distribution secure against coherent attacks

Cited by 163 publications

References 68 publications

Finite-key security analysis for quantum key distribution with leaky sources

Finite-key security analysis for quantum key distribution with leaky sources

Quantum-to-the-Home: Achieving Gbits/s Secure Key Rates via Commercial Off-the-Shelf Telecommunication Equipment

Long-distance transmission of quantum key distribution coexisting with classical optical communication over a weakly-coupled few-mode fiber

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