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Entanglement swapping is a fundamental protocol in quantum information processing that enables the distribution of entanglement between distant quantum systems. In this work, we first extend the concept of entanglement swapping to…

Quantum Physics · Physics 2025-08-04 S. M. Zangi , Chitra Shukla , Khalid Naseer , Saeed Haddadi

We devise a simple modification that essentially doubles the efficiency of the BB84 quantum key distribution scheme proposed by Bennett and Brassard. We also prove the security of our modified scheme against the most general eavesdropping…

Quantum Physics · Physics 2016-09-08 Hoi-Kwong Lo , H. F. Chau , M. Ardehali

Quantum Key Distribution (QKD) allows unconditionally secure communication based on the laws of quantum mechanics rather then assumptions about computational hardness. Optimizing the operation parameters of a given QKD implementation is…

A quantum key distribution and identification protocol is proposed, which is based on entanglement swapping. Through choosing particles by twos from the sequence and performing Bell measurements, two communicators can detect eavesdropping,…

Quantum Physics · Physics 2007-05-23 Fei Gao , Fenzhuo Guo , Qiaoyan Wen , Fuchen Zhu

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

This paper suggests an improvement to the BB84 scheme in Quantum key distribution. The original scheme has its weakness in letting quantifiably more information gain to an eavesdropper during public announcement of unencrypted bases lists.…

Quantum Physics · Physics 2007-05-23 C. Sanjeevakumar , M. Kasi Rajan , L. Sudarsan , R. Venkatesh , N. Srinivasan

Quantum key distribution (QKD) establishes secure links between remote communication parties. As a key problem for various QKD protocols, security analysis gives the amount of secure keys regardless of the eavesdropper's computational…

Quantum Physics · Physics 2023-09-26 Hongyi Zhou , Toshihiko Sasaki , Masato Koashi

We report a free-space entanglement-based quantum key distribution experiment, implementing the biased basis protocol between two sites which are 15.3 km apart. Photon pairs from a polarization-entangled source are distributed through two…

We consider the Bennett-Brassard cryptographic scheme, which uses two conjugate quantum bases. An eavesdropper who attempts to obtain information on qubits sent in one of the bases causes a disturbance to qubits sent in the other basis. We…

Quantum Physics · Physics 2007-05-23 Christopher A. Fuchs , Nicolas Gisin , Robert B. Griffiths , Chi-Sheng Niu , Asher Peres

Quantum key distribution (QKD) is a secure communication method that utilizes the principles of quantum mechanics to establish secret keys. The central task in the study of QKD is to prove security in the presence of an eavesdropper with…

Quantum Physics · Physics 2023-09-14 Sirui Peng , Xiaoming Sun , Hongyi Zhou

A practical quantum key distribution (QKD) protocol necessarily runs in finite time and, hence, only a finite amount of communication is exchanged. This is in contrast to most of the standard results on the security of QKD, which only hold…

Quantum Physics · Physics 2009-01-08 Valerio Scarani , Renato Renner

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…

In conventional quantum key distribution protocols, the secure key is normally extracted from the measurement outcomes of the system. Here, a different approach is proposed, where the secure key is extracted from the measurement bases,…

Quantum Physics · Physics 2014-10-21 Xiongfeng Ma

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) protocols aim at allowing two parties to generate a secret shared key. While many QKD protocols have been proven unconditionally secure in theory, practical security analyses of experimental QKD…

Quantum Physics · Physics 2023-07-04 Michel Boyer , Gilles Brassard , Nicolas Godbout , Rotem Liss , Stéphane Virally

A precise security analysis of practical quantum key distribution (QKD) systems is an important step for improving their performance. Here we consider a class of quantum soft filtering operations, which generalizes the unambiguous state…

Quantum Physics · Physics 2020-03-25 D. A. Kronberg , A. S. Nikolaeva , Y. V. Kurochkin , A. K. Fedorov

A quantum key distribution protocol based on entanglement swapping is proposed. Through choosing particles by twos from the sequence and performing Bell measurements, two communicators can detect eavesdropping and obtain the secure key.…

Quantum Physics · Physics 2007-05-23 Fei Gao , Fenzhuo Guo , Qiaoyan Wen , Fuchen Zhu

We report two key distribution schemes achieved by swapping quantum entanglement. Using two Bell states, two bits of secret key can be shared between two distant parties that play symmetric and equal roles. We also address eavesdropping…

Quantum Physics · Physics 2009-11-10 Daegene Song

We present a new technique for proving the security of quantum key distribution (QKD) protocols. It is based on direct information-theoretic arguments and thus also applies if no equivalent entanglement purification scheme can be found.…

Quantum Physics · Physics 2009-11-11 R. Renner , N. Gisin , B. Kraus

In this work we present a security analysis for quantum key distribution, establishing a rigorous tradeoff between various protocol and security parameters for a class of entanglement-based and prepare-and-measure protocols. The goal of…

Quantum Physics · Physics 2017-08-15 Marco Tomamichel , Anthony Leverrier