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We have implemented an experimental set-up in order to demonstrate the feasibility of time-coding protocols for quantum key distribution. Alice produces coherent 20 ns faint pulses of light at 853 nm. They are sent to Bob with delay 0 ns…

Quantum Physics · Physics 2007-05-23 William Boucher , Thierry Debuisschert

We study the problem of secret key distillation from bipartite states in the scenario where Alice and Bob can only perform measurements at the single-copy level and classically process the obtained outcomes. Even with these limitations,…

Quantum Physics · Physics 2009-11-10 Antonio Acin , Lluis Masanes , Nicolas Gisin

Twin-Field (TF) quantum key distribution (QKD) is a major candidate to be the new benchmark for far-distance QKD implementations, since its secret key rate can overcome the repeaterless bound by means of a simple interferometric…

Quantum Physics · Physics 2019-11-15 Federico Grasselli , Alvaro Navarrete , Marcos Curty

We extend the spherical code based key distribution protocols to qudits with dimensions 4 and 16 by constructing equiangular frames and their companions. We provide methods for equiangular frames in arbitrary dimensions for Alice to use and…

Quantum cryptographic key distribution (QKD) uses extremely faint light pulses to carry quantum information between two parties (Alice and Bob), allowing them to generate a shared, secret cryptographic key. Autocompensating QKD systems…

Quantum Physics · Physics 2009-11-07 Donald S. Bethune , William P. Risk

In recent years Quantum Key Distribution (QKD) has emerged as the most paradigmatic example of Quantum technology allowing the realization of intrinsically secure communication links over hundreds of kilometers. Beyond its commercial…

Quantum Physics · Physics 2013-04-15 A. Avella , G. Brida , D. Carpentras , A. Cavanna , I. P. Degiovanni , M. Genovese , M. Gramegna , P. Traina

Quantum key distribution, which allows two distant parties to share an unconditionally secure cryptographic key, promises to play an important role in the future of communication. For this reason such technique has attracted many…

Quantum Key Distribution (QKD) provides an efficient means to exchange information in an unconditionally secure way. Historically, QKD protocols have been based on binary signal formats, such as two polarisation states, and the transmitted…

Two-qubit quantum codes have been suggested to obtain better efficiency and higher loss tolerance in quantum key distribution. Here, we propose a two-qubit quantum key distribution protocol based on a mixed basis consisting of two Bell…

Quantum Physics · Physics 2017-09-20 Mladen Pavicic , Oliver Benson , Andreas W. Schell , Janik Wolters

In this paper, we propose a quantum key distribution (QKD) protocol based on only a two-dimensional Hilbert space encoding a quantum system and independent devices between the equipment for state preparation and measurement. Our protocol is…

Quantum Physics · Physics 2015-06-18 Hong-Wei Li , Zhen-Qiang Yin , Wei Chen , Shuang Wang , Guang-Can Guo , Zheng-Fu Han

We initially consider a quantum system consisting of two qubits, which can be in one of two nonorthogonal states, \Psi_0 or \Psi_1. We distribute the qubits to two parties, Alice and Bob. They each measure their qubit and then compare their…

Quantum Physics · Physics 2009-11-11 Jihane Mimih , Mark Hillery

The best qubit one-way quantum key distribution (QKD) protocol can tolerate up to 14.1% in the error rate. It has been shown how this rate can be increased by using larger quantum systems. The polarization state of a biphoton can encode a…

Quantum Physics · Physics 2009-11-13 I. Bregman , D. Aharonov , M. Ben-Or , H. S. Eisenberg

Mutually unbiased bases have been extensively studied in the literature and are simple and effective in quantum key distribution protocols, but they are not optimal. Here equiangular spherical codes are introduced as a more efficient and…

Quantum Physics · Physics 2016-02-23 Joseph M. Renes

Quantum key distribution (QKD) exploits the quantum nature of light to share provably secure keys, allowing secure communication in the presence of an eavesdropper. The first QKD schemes used photons encoded in two states, such as…

We introduce a constructive method to calculate the achievable secret key rate for a generic class of quantum key distribution protocols, when only a finite number n of signals is given. Our approach is applicable to all scenarios in which…

Quantum Physics · Physics 2007-05-23 Tim Meyer , Hermann Kampermann , Matthias Kleinmann , Dagmar Bruss

Quantum secret-sharing protocols involving N partners (NQSS) are key distribution protocols in which Alice encodes her key into $N-1$ qubits, in such a way that all the other partners must cooperate in order to retrieve the key. On these…

Quantum Physics · Physics 2009-11-07 Valerio Scarani , Nicolas Gisin

Semi-quantum key distribution (SQKD) protocols attempt to establish a shared secret key between users, secure against computationally unbounded adversaries. Unlike standard quantum key distribution protocols, SQKD protocols contain at least…

Quantum Physics · Physics 2022-03-22 Saachi Mutreja , Walter O. Krawec

Unconditional security in quantum key distribution (QKD) relies on authenticating the identities of users involved in key distribution. While classical identity authentication schemes were initially utilized in QKD implementations, concerns…

Quantum Physics · Physics 2025-02-13 Arindam Dutta , Anirban Pathak

We introduce a new continuous-variable quantum key distribution (CV-QKD) protocol, self-referenced CV-QKD, that eliminates the need for transmission of a high-power local oscillator between the communicating parties. In this protocol, each…

This study proposes a new lightweight quantum key distribution (LQKD) protocol based on the four-particle cluster state within a quantum-restricted environment. The protocol enables a quantum-capable user to simultaneously establish two…

Quantum Physics · Physics 2025-07-16 Mustapha Anis Younes , Sofia Zebboudj , Abdelhakim Gharbi