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Related papers: Analytical bounds for decoy-state quantum key dist…

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In this paper, we present a flowchart-based description of the decoy-state BB84 quantum key distribution (QKD) protocol and provide a step-by-step, self-contained information-theoretic security proof for this protocol within the universal…

Quantum Physics · Physics 2025-05-27 Akihiro Mizutani , Toshihiko Sasaki , Go Kato

Quantum key distribution (QKD) utilizes the laws of quantum mechanics to achieve information-theoretically secure key generation. This field is now approaching the stage of commercialization, but many practical QKD systems still suffer from…

Quantum key distribution (QKD) based on coherent states is well known for its implementation simplicity, but it suffers from loss-dependent attacks based on optimal unambiguous state discrimination. Crucially, previous research has…

Quantum Physics · Physics 2020-06-05 Li Liu , Yukun Wang , Emilien Lavie , Arno Ricou , Chao Wang , Fen Zhuo Guo , Charles Ci Wen Lim

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…

Quantum Physics · Physics 2018-09-05 Weilong Wang , Kiyoshi Tamaki , Marcos Curty

Numerical security proofs offer a versatile approach for evaluating the secret-key generation rate of quantum key distribution (QKD) protocols. However, existing methods typically require perfect source characterization, which is…

Variations of phase-matching measurement-device-independent quantum key distribution (PM-MDI QKD) protocols have been investigated before, but it was recently discovered that this type of protocol (under the name of twin-field QKD) can beat…

Quantum Physics · Physics 2018-10-30 Jie Lin , Norbert Lütkenhaus

The security of a standard bi-directional "plug & play" quantum key distribution (QKD) system has been an open question for a long time. This is mainly because its source is equivalently controlled by an eavesdropper, which means the source…

Quantum Physics · Physics 2009-11-13 Yi Zhao , Bing Qi , Hoi-Kwong Lo

We present a rigorous and complete security proof of the decoy-state BB84 quantum key distribution (QKD) protocol. Our analysis aims to achieve a high standard of mathematical rigour and completeness, thereby providing the necessary…

Quantum Physics · Physics 2026-01-27 Devashish Tupkary , Shlok Nahar , Amir Arqand , Ernest Y. -Z. Tan , Norbert Lütkenhaus

The decoy-state Bennett-Brassard 1984 (BB84) quantum key distribution (QKD) protocol is widely regarded as the de facto standard for practical implementations. On the receiver side, passive basis choice is attractive because it…

Quantum Physics · Physics 2025-11-27 Akihiro Mizutani , Shun Kawakami , Go Kato

Ideal quantum key distribution (QKD) protocols call for a source that emits single photon signals, but the sources used in typical practical realizations emit weak coherent states instead. A weak coherent state may contain more than one…

Quantum Physics · Physics 2007-05-23 Hoi-Kwong Lo , John Preskill

Quantum key distribution (QKD) is known to be unconditionally secure in principle, but quantifying the security of QKD protocols from a practical standpoint continues to remain an important challenge. Here, we focus on phase-based QKD…

Quantum Physics · Physics 2024-03-13 Valliamai Ramanathan , Anil Prabhakar , Prabha Mandayam

Quantum key distribution (QKD) allows two users to communicate with theoretically provable secrecy by encoding information on photonic qubits. Current encoders are complex, however, which reduces their appeal for practical use and…

Decoy-state quantum key distribution (QKD) is a standard technique in current quantum cryptographic implementations. Unfortunately, existing experiments have two important drawbacks: the state preparation is assumed to be perfect without…

Quantum Physics · Physics 2015-09-09 Feihu Xu , Kejin Wei , Shihan Sajeed , Sarah Kaiser , Shihai Sun , Zhiyuan Tang , Li Qian , Vadim Makarov , Hoi-Kwong Lo

While ideal quantum key distribution (QKD) systems are well-understood, practical implementations face various vulnerabilities, such as side-channel attacks resulting from device imperfections. Current security proofs for decoy-state BB84…

Quantum Physics · Physics 2025-06-18 Jerome Wiesemann , Fadri Grünenfelder , Ana Blázquez , Nino Walenta , Davide Rusca

Due to its ability to tolerate high channel loss, decoy-state quantum key distribution (QKD) has been one of the main focuses within the QKD community. Notably, several experimental groups have demonstrated that it is secure and feasible…

Quantum Physics · Physics 2014-02-12 Charles Ci Wen Lim , Marcos Curty , Nino Walenta , Feihu Xu , Hugo Zbinden

A realistic Quantum Key Distribution (QKD) protocol necessarily deals with finite resources, such as the number of signals exchanged by the two parties. We derive a bound on the secret key rate which is expressed as an optimization problem…

Quantum Physics · Physics 2011-10-13 Silvestre Abruzzo , Hermann Kampermann , Markus Mertz , Dagmar Bruß

The performance of quantum key distribution (QKD) protocols is evaluated based on the ease of implementation and key generation rate. Among major protocols, the differential-phase-shift (DPS) protocol has the advantage of simple…

Quantum Physics · Physics 2024-12-24 Akihiro Mizutani , Toyohiro Tsurumaru

In quantum key distribution (QKD), the bit error rate is used to estimate the information leakage and hence determines the amount of privacy amplification --- making the final key private by shortening the key. In general, there exists a…

The decoy-state method is a standard enhancement to quantum key distribution (QKD) protocols that has enabled countless QKD experiments with inexpensive light sources. However, new technological advancements might require further…

Phase randomization is an important assumption made in many security proofs of practical quantum key distribution (QKD) systems. Here, we present the first experimental demonstration of QKD with reliable active phase randomization. One key…

Quantum Physics · Physics 2009-11-13 Yi Zhao , Bing Qi , Hoi-Kwong Lo