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Related papers: A Fair Sampling Test for Ekert Protocol

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A scheme is proposed by which two parties, Alice and Bob, can securely exchange real numbers. The scheme requires Alice and Bob to share entanglement and both to perform Bell-state measurements. With a qubit system two real numbers can each…

Quantum Physics · Physics 2007-05-23 Sung Soon Jang , Hai-Woong Lee

We present a fair and optimistic quantum contract signing protocol between two clients that requires no communication with the third trusted party during the exchange phase. We discuss its fairness and show that it is possible to design…

Quantum Physics · Physics 2015-05-28 N. Paunkovic , J. Bouda , P. Mateus

I present an eavesdropping on the protocol proposed by W.-H. Kye, et al. [Phys. Rev. Lett. 95, 040501 (2005)]. I show how an undetectable Eve can steal the whole information by labeling and then measuring the photons prepared by the user…

Quantum Physics · Physics 2007-05-23 Marco Lucamarini

Nonlocal games with synchronous correlations are a natural generalization of functions between two finite sets. In this work we examine analogues of Bell's inequalities for such correlations, and derive a synchronous device-independent…

Quantum Physics · Physics 2020-04-20 Nishant Rodrigues , Brad Lackey

Recently, Liu W et al. proposed a two-party quantum private comparison (QPC) protocol using entanglement swapping of Bell entangled state (Commun. Theor. Phys. 57(2012)583-588). Subsequently, Liu W J et al. pointed out that in Liu W et…

Quantum Physics · Physics 2022-05-18 Tian-Yu Ye

Certifying maximal quantum randomness without assumptions about system dimension remains a pivotal challenge for secure communication and foundational studies. Here, we introduce a generalized framework to directly certify maximal…

Quantum Physics · Physics 2025-07-15 Tianqi Zheng , Yi Li , Yu Xiang , Qiongyi He

The security of quantum cryptography is guaranteed by the no-cloning theorem, which implies that an eavesdropper copying transmitted qubits in unknown states causes their disturbance. Nevertheless, in real cryptographic systems some level…

Quantum Physics · Physics 2013-05-06 Karol Bartkiewicz , Karel Lemr , Antonín Černoch , Jan Soubusta , Adam Miranowicz

A central challenge in the verification of quantum computers is benchmarking their performance as a whole and demonstrating their computational capabilities. In this work, we find a universal model of quantum computation, Bell sampling,…

Quantum Physics · Physics 2024-07-10 Dominik Hangleiter , Michael J. Gullans

This paper proposes a new protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than…

Bell-inequality violations establish that two systems share some quantum entanglement. We give a simple test to certify that two systems share an asymptotically large amount of entanglement, n EPR states. The test is efficient: unlike…

Quantum Physics · Physics 2018-09-06 Rui Chao , Ben W. Reichardt , Chris Sutherland , Thomas Vidick

An efficiency-loophole-free quantum key distribution (QKD) scheme is proposed, which involves no hardware change but a modification in the data post-processing step. The scheme applies to a generic class of detection systems which allow…

Quantum Physics · Physics 2008-12-24 Xiongfeng Ma , Tobias Moroder , Norbert Lütkenhaus

We have examined the effect of the decoherence in the Ekert91 quantum cryptographic protocol. In order to explore this issue we have introduced two major decoherences, the depolarizing channel and the generalized amplitude damping, between…

Quantum Physics · Physics 2009-06-02 DaeKil Park , Jin-Woo Son , Seong-Keuck Cha , Eun Deock Seo

We investigate how accidental counts, the detection events not originating from genuine entangled photon pairs, impact the observed violation of Bell inequalities in photonic experiments. These false coincidences become increasingly…

Quantum Physics · Physics 2025-07-29 Piotr Mironowicz , Mohamed Bourennane

A quantum key distribution protocol is proposed that is a variation of BB84 that provides raw key generation from correlations that violate a Bell-type inequality for single qubit systems and not entangled pairs. Additionally, it 1) is…

Quantum Physics · Physics 2020-03-24 Radha Pyari Sandhir

Recently, Boyer et al. presented a novel semiquantum key distribution protocol [M. Boyer, D. Kenigsberg, and T. Mor, Phys. Rev. Lett. 99, 140501 (2007)], by using four quantum states, each of which is randomly prepared by Z basis or X…

Quantum Physics · Physics 2015-05-27 Jian Wang , Sheng Zhang , Quan Zhang , Chao-Jing Tang

Over the past few decades, experimental tests of Bell-type inequalities have been at the forefront of understanding quantum mechanics and its implications. These strong bounds on specific measurements on a physical system originate from…

Quantum key distribution (QKD) systems can send signals over more than 100 km standard optical fiber and are widely believed to be secure. Here, we show experimentally for the first time a technologically feasible attack, namely the…

Quantum Physics · Physics 2011-04-05 Yi Zhao , Chi-Hang Fred Fung , Bing Qi , Christine Chen , Hoi-Kwong Lo

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

A recent experiment presented, for photons, the first violation of a Bell inequality closing the fair-sampling loophole, i.e., without having to assume that the sample of measured photons fairly represents the entire ensemble. In this note,…

Quantum Physics · Physics 2013-07-25 Johannes Kofler , Sven Ramelow , Marissa Giustina , Anton Zeilinger

Experiments showing the violation of Bell inequalities have formed our belief that the world at its smallest is genuinely non-local. While many non-locality experiments use the first quantised picture, the physics of fields of…

Quantum Physics · Physics 2013-05-29 Libby Heaney , Janet Anders