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We propose the improved decoy state quantum key distribution incorporating finite statistics due to the finite code length and report on its demonstration. In our experiment, four different intensities including the vacuum state for optimal…

Quantum Physics · Physics 2007-05-23 Jun Hasegawa , Masahito Hayashi , Tohya Hiroshima , Akihiro Tanaka , Akihisa Tomita

To improve the performance of a quantum key distribution (QKD) system, high speed, low dark count single photon detectors (or low noise homodyne detectors) are required. However, in practice, a fast detector is usually noisy. Here, we…

Quantum Physics · Physics 2009-11-13 Bing Qi , Yi Zhao , Xiongfeng Ma , Hoi-Kwong Lo , Li Qian

The practical realizations of BB84 quantum key distribution protocol using single-photon or weak coherent states have normally presented low efficiency, in the meaning that most bits sent by Alice are not useful for the final key. In this…

Quantum Physics · Physics 2007-05-23 Fabio Alencar Mendonca , Rubens Viana Ramos

Quantum key distribution is a way to distribute secret keys to distant users with information theoretic security and key rates suitable for real-world applications. Its rate-distance figure, however, is limited by the natural loss of the…

Quantum Physics · Physics 2018-09-12 Kiyoshi Tamaki , Hoi-Kwong Lo , Wenyuan Wang , Marco Lucamarini

Afterpulsing is a factor limiting the distance over which discrete-variable quantum key distribution systems are secure, and a common feature in single-photon detectors. The relevance of this phenomenon stems from its stochastic,…

We introduce a quantum key distribution protocol designed to expose fake users that connect to Alice or Bob for the purpose of monopolising the link and denying service. It inherently resists attempts to exhaust Alice and Bob's initial…

Quantum Physics · Physics 2017-11-15 Alasdair B. Price , John G. Rarity , Chris Erven

Quantum technology can enable secure communication for cryptography purposes using quantum key distribution. Quantum key distribution protocols provide a secret key between two users with security guaranteed by the laws of quantum…

Quantum Physics · Physics 2024-10-11 Venkat Abhignan , Abhishek Jamunkar , Gokul Nair , Mohit Mittal , Megha Shrivastava

Compared with two-level quantum key distribution (QKD), highdimensional QKD enable two distant parties to share a secret key at a higher rate. We provide a finite-key security analysis for the recently proposed practical highdimensional…

Quantum Physics · Physics 2016-06-08 Haize Bao , Wansu Bao , Yang Wang , Chun Zhou , Ruike Chen

We propose efficient-phase-encoding protocols for continuous-variable quantum key distribution using coherent states and postselection. By these phase encodings, the probability of basis mismatch is reduced and total efficiency is…

Quantum Physics · Physics 2008-09-29 Ryo Namiki , Takuya Hirano

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

In the original BB84 protocol by Bennett and Brassard, an eavesdropper is detected because his attempts to intercept information result in a quantum bit error rate (QBER) of at least 25%. Here we design an alternative quantum key…

Quantum Physics · Physics 2015-05-13 Muhammad Mubashir Khan , Michael Murphy , Almut Beige

The quantum key distribution for multiparty is one of the essential subjects of study. Especially, without using entangled states, performing the quantum key distribution for multiparty is a critical area of research. For this purpose,…

Quantum Physics · Physics 2023-09-27 Min Namkung , Younghun Kwon

In semiquantum key-distribution (Boyer et al.) Alice has the same capability as in BB84 protocol, but Bob can measure and prepare qubits only in $\{|0\rangle, |1\rangle\}$ basis and reflect any other qubit. We study an eavesdropping…

Quantum Physics · Physics 2015-01-30 Arpita Maitra , Goutam Paul

We propose a quantum key distribution scheme that combines a biased basis choice with the decoy-state method. In this scheme, Alice sends all signal states in the $Z$ basis and decoy states in the $X$ and $Z$ basis with certain…

Quantum Physics · Physics 2013-08-20 Zhengchao Wei , Weilong Wang , Zhen Zhang , Ming Gao , Zhi Ma , Xiongfeng Ma

We propose a rotationally-invariant quantum key distribution scheme that uses a pair of orthogonal qubit trines, realized as mixed states of three physical qubits. The measurement outcomes do not depend on how Alice and Bob choose their…

Quantum Physics · Physics 2015-05-14 Gelo Tabia , Berthold-Georg Englert

In contrast to classical public-key cryptosystems, where the security of encoded messages relies on on computational assumptions, Quantum Key Distribution (QKD) enables two distant parties to establish a shared secret key that, when…

Twin-field quantum key distribution (TF-QKD) and its variants can overcome the fundamental rate-distance limit of QKD which has been demonstrated in the laboratory and field while their physical implementations with side channels remains to…

Quantum Physics · Physics 2021-09-08 Yi-Fei Lu , Mu-Sheng Jiang , Yang Wang , Xiao-Xu Zhang , Fan Liu , Chun Zhou , Hong-Wei Li , Wan-Su Bao

The use of quantum bits (qubits) in cryptography holds the promise of secure cryptographic quantum key distribution schemes. Unfortunately, the implemented schemes can be totally insecure. We provide a thorough investigation of security…

Quantum Physics · Physics 2009-10-31 Gilles Brassard , Norbert Lütkenhaus , Tal Mor , Barry C. Sanders

Quantum key distribution protocols typically make use of a one-way quantum channel to distribute a shared secret string to two distant users. However, protocols exploiting a two-way quantum channel have been proposed as an alternative route…

Quantum Physics · Physics 2013-12-13 Normand J. Beaudry , Marco Lucamarini , Stefano Mancini , Renato Renner

Prepare and measure quantum key distribution protocols can be decomposed into two basic steps: delivery of the signals over a quantum channel and distillation of a secret key from the signal and measurement records by classical processing…

Quantum Physics · Physics 2007-05-23 Joseph M. Renes , Markus Grassl