scholarly journals Optimal Design of Practical Quantum Key Distribution Backbones for Securing CoreTransport Networks

2020 ◽  
Vol 2 (1) ◽  
pp. 114-125 ◽  
Author(s):  
Federico Pederzolli ◽  
Francescomaria Faticanti ◽  
Domenico Siracusa

We describe two mixed-integer linear programming formulations, one a faster version of a previous proposal, the other a slower but better performing new model, for the design of Quantum Key Distribution (QKD) sub-networks dimensioned to secure existing core fiber plants. We exploit existing technologies, including non-quantum repeater nodes and multiple disjoint QKD paths to overcome reach limitations while maintaining security guarantees. We examine the models’ performance using simulations on both synthetic and real topologies, quantifying their time and resulting QKD network cost compared to our previous proposal.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hua-Lei Yin ◽  
Zeng-Bing Chen

AbstractLong-distance quantum key distribution (QKD) has long time seriously relied on trusted relay or quantum repeater, which either has security threat or is far from practical implementation. Recently, a solution called twin-field (TF) QKD and its variants have been proposed to overcome this challenge. However, most security proofs are complicated, a majority of which could only ensure security against collective attacks. Until now, the full and simple security proof can only be provided with asymptotic resource assumption. Here, we provide a composable finite-key analysis for coherent-state-based TF-QKD with rigorous security proof against general attacks. Furthermore, we develop the optimal statistical fluctuation analysis method to significantly improve secret key rate in high-loss regime. The results show that coherent-state-based TF-QKD is practical and feasible, with the potential to apply over nearly one thousand kilometers.


2014 ◽  
Author(s):  
Ping Wang ◽  
Xi Zhang ◽  
Genshe Chen ◽  
Khanh Pham ◽  
Erik Blasch

2020 ◽  
Vol 6 (37) ◽  
pp. eaaz4487 ◽  
Author(s):  
Margarida Pereira ◽  
Go Kato ◽  
Akihiro Mizutani ◽  
Marcos Curty ◽  
Kiyoshi Tamaki

In theory, quantum key distribution (QKD) offers information-theoretic security. In practice, however, it does not due to the discrepancies between the assumptions used in the security proofs and the behavior of the real apparatuses. Recent years have witnessed a tremendous effort to fill the gap, but the treatment of correlations among pulses has remained a major elusive problem. Here, we close this gap by introducing a simple yet general method to prove the security of QKD with arbitrarily long-range pulse correlations. Our method is compatible with those security proofs that accommodate all the other typical device imperfections, thus paving the way toward achieving implementation security in QKD with arbitrary flawed devices. Moreover, we introduce a new framework for security proofs, which we call the reference technique. This framework includes existing security proofs as special cases, and it can be widely applied to a number of QKD protocols.


2011 ◽  
Vol 11 (7&8) ◽  
pp. 615-637
Author(s):  
Tzonelih Hwang ◽  
Chia-Wei Tsai ◽  
Song-Kong Chong

This work presents a new concept in quantum key distribution called the probabilistic quantum key distribution (PQKD) protocol, which is based on the measurement uncertainty in quantum phenomena. It allows two mutually untrusted communicants to negotiate an unpredictable key that has a randomness guaranteed by the laws of quantum mechanics. In contrast to conventional QKD (e.g., BB84) in which one communicant has to trust the other for key distribution or quantum key agreement (QKA) in which the communicants have to artificially contribute subkeys to a negotiating key, PQKD is a natural and simple method for distributing a secure random key. The communicants in the illustrated PQKD take Einstein-Podolsky-Rosen (EPR) pairs as quantum resources and then use entanglement swapping and Bell-measurements to negotiate an unpredictable key.


2003 ◽  
Vol 14 (06) ◽  
pp. 757-763 ◽  
Author(s):  
XIAOYU LI

In this paper we provide a quantum key distribution (QKD) scheme based on the correlations of Einstein–Podolsky–Rosen (EPR) pairs. The scheme uses an auxiliary qubit to interact with the EPR pair and does the Bell state measurement to get the key. It is proved to be secure. All EPR pairs are used in distributing the key except some error-checking bits. So it is efficient. On the other hand there are less classical communications needed in the scheme.


2006 ◽  
Vol 04 (05) ◽  
pp. 769-779 ◽  
Author(s):  
FENZHUO GUO ◽  
TAILIN LIU ◽  
QIAOYAN WEN ◽  
FUCHEN ZHU

Based on entanglement swapping between two Bell states, two novel quantum key distribution protocols are proposed. One is for two-level systems, where there is no need for classical communication before each entanglement swapping. This feature is essential to its practical realization. Furthermore, to establish an arbitrarily long key, the protocol needs only two Bell states. The other is for d-level (d > 2) systems, in which higher security and higher source capacity are achieved. Using the theory of quadratic residue, we prove that in the two-qudit systems, each Bell state is a uniform superposition of all basis states in the dual basis, which is different to the situation in two-qubit systems. This difference means our two-level protocol cannot be generalized to the d-level situation directly. On the other hand, it results in higher security of our d-level protocol and is instructive to design quantum cryptography protocols.


2018 ◽  
Vol 8 (10) ◽  
pp. 1951 ◽  
Author(s):  
Fei Li ◽  
Hai Zhong ◽  
Yijun Wang ◽  
Ye Kang ◽  
Duan Huang ◽  
...  

Performance analysis of continuous-variable quantum key distribution (CVQKD) has been one of the focuses of quantum communications. In this paper, we propose an approach to enhancing the secret rate of CVQKD with the multi-core fiber (MCF) system that transmits multiple spatial modes simultaneously. The excess noise contributed by the inter-core crosstalk between cores can be effectively suppressed by quantum channel wavelength management, leading to the performance improvement of the MCF-based CVQKD system. In the security analysis, we perform numerical simulations for the Gaussian-modulated coherent state CVQKD protocol, considering simultaneously the extra insert loss of fan-in/fan-out (FIFO), which is the extra optical device that should be used at the input and the output of the fiber. Simulation results show that the performance of the one-way and two-way protocols for each core are slightly degraded because of the insert loss of the FIFO, but the total secret key rate can be increased, whereas the performance of the measurement-device-independent CVQKD protocol will be degraded due to the effect of the insert loss of the FIFO. These results may provide theoretical foundation for the space-division multiplexing CVQKD system.


Author(s):  
Hiroo Azuma ◽  
Masashi Ban

We investigate the security against the intercept/resend and translucent attacks on the quantum key distribution protocol based on the pre- and post-selection effect. In 2001, Bub proposed the quantum cryptography scheme, which was an application of the so-called mean king’s problem. We evaluate a probability that legitimate users cannot detect eavesdropper’s malicious acts for Bub’s protocol. We also estimate a probability that the eavesdropper guesses right at the random secret key one of the legitimate users tries to share with the other one. From rigorous mathematical and numerical analyses, we conclude that Bub’s protocol is weaker than the Bennett–Brassard protocol of 1984 (BB84) against both the intercept/resend and translucent attacks. Because Bub’s protocol uses a two-way quantum channel, the analyses of its security are tough to accomplish. We refer to their technical points accurately in the current paper. For example, we impose some constraints upon the eavesdropper’s strategies in order to let their degrees of freedom be small.


2005 ◽  
Vol 03 (03) ◽  
pp. 555-560 ◽  
Author(s):  
ZHAN-JUN ZHANG ◽  
ZHONG-XIAO MAN ◽  
SHOU-HUA SHI

We propose a quantum key distribution (QKD) scheme in which four parties can simultaneously share a secret key via optical device. The participants divide the communication into two modes, namely, detecting mode and message mode. Taking advantage of controlled secret short key technology, the participants together can achieve the detecting mode or the message mode by switching between their two sets of optical devices. In the detecting mode, the key distributer Alice utilizes a single-photon state resource and two beam splitters and the other three participants Bob, Charlie and Dick use first-type devices to detect the superposition of vacuum and single-particle states. Hence, any eavesdropping can be found by using a variant of Bell's inequality. In the message mode, Alice uses a two-photon Bell-state resource and two polarization beam splitters instead of the single-particle state resource and beam splitters used in the detecting mode and the other three participants use second-type devices to detect photons. In this case, the secret key can be successfully distributed from Alice to the other three ones. Moreover, the present four-party QKD scheme can be generalized to a 2n-party QKD scheme by using n-photon Greenberg–Horne–Zeilinger.


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