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We present two polarization-based protocols for quantum key distribution. The protocols encode key bits in noiseless subspaces or subsystems, and so can function over a quantum channel subjected to an arbitrary degree of collective noise,…

Quantum Physics · Physics 2009-11-10 J. -C. Boileau , D. Gottesman , R. Laflamme , D. Poulin , R. W. Spekkens

In this project we examine several different quantum key distribution protocols which we divide into ones utilizing qubits whose Hilbert spaces are two dimensional and ones whose Hilbert space dimension is greater than two, these units of…

Quantum Physics · Physics 2024-02-05 Yuval Idan , Avihai Didi

We report on a complete experimental implementation of a quantum key distribution protocol through a free space link using polarization-entangled photon pairs from a compact parametric down-conversion source. Over 10 hours of uninterrupted…

Quantum Physics · Physics 2007-05-23 Ivan Marcikic , Antia Lamas-Linares , Christian Kurtsiefer

We investigate entanglement-based quantum key distribution protocols, with particular emphasis on their efficiency under realistic conditions of satellite quantum communications, where performance is limited by the low power of a received…

Quantum Physics · Physics 2026-05-21 Vera Uzunova , Marcin Jarzyna

We present an experimental demonstration of a quantum key distribution protocol using coherent polarization states. Post selection is used to ensure a low error rate and security against beam splitting attacks even in the presence of high…

Quantum Physics · Physics 2007-05-23 Stefan Lorenz , Natalia Korolkova , Gerd Leuchs

Quantum Key Distribution is a quantum communication technique in which random numbers are encoded on quantum systems, usually photons, and sent from one party, Alice, to another, Bob. Using the data sent via the quantum signals,…

Quantum Physics · Physics 2014-09-09 T. C. Ralph , N. Walk

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…

In recent years quantum information research has lead to the discovery of a number of remarkable new paradigms for information processing and communication. These developments include quantum cryptography schemes that offer unconditionally…

In this paper, we present a scheme for quantum key distribution, in which different-frequency photons are used to encode the key. Thses different-frequency photons are produced by an acoustic-optical modulator and two kinds of narrow…

Quantum Physics · Physics 2009-11-06 Bao-Sen Shi , Yun-Kun Jiang , Guang-Can Guo

A quantum key distribution system has been developed, using standard telecommunications optical fiber, which is capable of operating at clock rates of greater than 1 GHz. The quantum key distribution system implements a polarization encoded…

Quantum Physics · Physics 2007-05-23 Karen J. Gordon , Veronica Fernandez , Paul D. Townsend , Gerald S. Buller

Now that fundamental quantum principles of indeterminacy and measurement have become the basis of new technologies that provide secrecy between two communicating parties, there is a need to provide teaching laboratories that illustrate how…

Quantum Physics · Physics 2021-02-03 Aayam Bista , Baibhav Sharma , Enrique J. Galvez

We present a scheme for key distribution based on bi-partite correlation of single photons. Alice keeps an ancilla photon and sends a signal photon to Bob, where intrinsic bi-partite correlation of these photons is obtained through first…

Quantum Physics · Physics 2012-07-23 Kim Fook Lee , Yong Meng Sua , Harith B. Ahmad

We demonstrate a prototype-implementation of deterministic information encoding for quantum key distribution (QKD) following the ping-pong coding protocol [K. Bostroem, T. Felbinger, Phys. Rev. Lett. 89 (2002) 187902-1]. Due to the…

Quantum Physics · Physics 2009-11-13 Martin Ostermeyer , Nino Walenta

We present a novel one-way quantum key distribution protocol based on 3-dimensional quantum state, a qutrit, that encodes two qubits in its 2-dimensional subspaces. The qubits hold the classical bit information that has to be shared between…

Quantum Physics · Physics 2012-02-03 R. Kumar , R. Demkowicz-Dobrzanski , K. Banaszek

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

A new scheme of Quantum Key Distribution is proposed using three entangled particles in a GHZ state. Alice holds a 3-particle source and sends two particles to Bob, keeping one with herself. Bob uses one particle to generate a secure key,…

Quantum Physics · Physics 2013-01-23 Tabish Qureshi , Tabish Shibli , Aditi Sheel

Secret sharing allows three or more parties to share secret information which can only be decrypted through collaboration. It complements quantum key distribution as a valuable resource for securely distributing information. Here we take…

Quantum Physics · Physics 2020-07-16 Michael de Oliveira , Isaac Nape , Jonathan Pinnell , Najmeh TabeBordbar , Andrew Forbes

In this paper we present quantum key distribution protocol that, instead of single qubits, uses mesoscopic coherent states of light $|\alpha\rangle$ to encode bit values of a randomly generated key. Given the reference value…

Quantum Physics · Physics 2017-05-04 G. A. Barbosa , J. van de Graaf , P. Mateus , N. Paunković

We discuss a continuous variables method of quantum key distribution employing strongly polarized coherent states of light. The key encoding is performed using the variables known as Stokes parameters, rather than the field quadratures.…

Quantum Physics · Physics 2016-02-15 A. Vidiella-Barranco , L. F. M. Borelli

We present an entangled-state quantum cryptography system that operated for the first time in a real world application scenario. The full key generation protocol was performed in real time between two distributed embedded hardware devices,…