Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:0805.3629 · Physical Review A

Experimental quantum key distribution based on a Bell test

Alexander Ling, Matthew P. Peloso, I. Marcikic, Valerio Scarani, Antı́a Lamas-Linares, Christian Kurtsiefer

Published Aug 20, 2008• 51 citations
arXivHTMLPDF

Abstract

We report on a complete free-space field implementation of a modified Ekert protocol for quantum key distribution using entangled photon pairs. For each photon pair we perform a random choice between key generation and a Bell inequality. The amount of violation is used to determine the possible knowledge of an eavesdropper to ensure security of the distributed final key.

DOI
10.1103/physreva.78.020301

Related papers

Entangled-photon quantum cryptography

Paul G. Kwiat, Andrew G. White, Charles G. Peterson +1 more

Summary form only given. Quantum cryptography uses single photons to allow secure distribution of secret key material to sender and receiver, without the possibility of an undetected eavesdropper. In the protocol suggested by Ekert, each photon of a quantum-mechanically entangled pair is sent to the sender and receiver, who randomly measure the polarization in various bases. If the bases are the same, then sender and receiver will have completely correlated measurement results, which become the shared secret key. Other combinations of measurements are used to test Bell's inequalities, which limit the possible correlations achievable with any local realistic theory. The presence of an intermediate eavesdropper can be readily detected by an inability to violate Bell's inequality. Using the polarization-entangled photon pairs from a novel spontaneous parametric down-conversion source, we have experimentally implemented. Ekert's proposal.

Quantum Electronics and Laser Science Conference•May 12, 2000•0 citations

A theoretical and experimental test on the security of quantum cryptography key distribution Ekert's protocol based on Wigner's inequality

Stefania Castelletto, Ivo Pietro Degiovanni, Maria Luisa Rastello +4 more

In this paper we prove both theoretically and experimentally the insecurity of the Ekert’s protocol for quantum-key distribution when based on the Wigner inequality when entangled photon pairs are used as source. The security proof of the Eckert’s protocol based on Wigner’s inequality consists in verifying the violation of W ≥ 0 (which corresponds to local-realistic theories). We highlight that a violation of the Wigner’s inequality occurs when Eve controls the two quantum channels. We give the theoretical motivation for this result and we perform an experiment proving this weakness, by realizing the condition of Eve gaining total control of the source of photon pairs. In addition we calculate the modified version of this inequality which guarantees safe quantum-key distribution, thus proving it experimentally.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Feb 3, 2004•0 citations

Quantum communication experiments with entangled photon pairs

Matej Peranić, Martin Lončarić, Anton Radman +1 more

Today, perhaps more than ever before, the security of information and communication is increasingly important. The cryptographic protocols used in classical cryptography are based on mathematical algorithms and can be breached. On the other hand, the laws of quantum physics enable quantum key distribution (QKD) and it is possible to achieve absolute security of communication based on the fundamental laws of nature. Anyone who would eavesdrop QKD-based communication must perform a measurement, which implies an impact on the system that can be detected by the sender and receiver. In this paper, we present a brief overview of QKD implementations and our experimental setup for generation of quantum key. Using this setup, we measured violation of the Bell's inequality of 114 standard deviations from the classical boundary, which confirms the non-local behavior of the entangled photon pairs. One can also use this source to create hybrid connections in combination with both optical fibers and free space.

International Convention on Information and Communication Technology, Electronics and Microelectronics•May 23, 2022•3 citations

Entanglement based free-space quantum key distribution

Chris Erven, Christophe Couteau, Raymond Laflamme +1 more

We report on the progress of our real-time entanglement based free-space quantum key distribution (QKD) system which uses polarization entangled photon pairs sent over a variety of free-space optical telescope links to distribute the key. An experiment with one photon from each pair sent over a 1,325 m long free-space link and the other photon detected locally next to the source is described. The system performs the complete QKD protocol including all error correction and privacy amplification algorithms. Over the course of 6.5 hours of communication at night an average raw key rate of 1,398 bits/s with an average quantum bit error rate (QBER) of 4.58% was observed producing an average final key rate of 244 bits/s. We also performed a Bell inequality experiment over two free-space links of 435 m and 1,325 m respectively, producing a total separation of 1,575 m between the two detectors in the experiment. During the Bell inequality experiment we observed an average Bell parameter of 2.51 ± 0.11.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 18, 2008•4 citations

A FAIR SAMPLING TEST FOR EKERT PROTOCOL

GUILLAUME ADENIER, NOBORU WATANABE, Andrei Yu. Khrennikov

We propose a local scheme to enhance the security of quantum key distribution in Ekert protocol (E91). Our proposal is a fair sampling test meant to detect an eavesdropping attempt that would use a biased sample to mimic an apparent violation of Bell inequalities. The test is local and non disruptive: it can be unilaterally performed at any time by either Alice or Bob during the production of the key, and together with the Bell inequality test.

arXiv:1004.1242•QP-PQ, quantum probability and white noise analysis•Jan 1, 2011•1 citation

Experimental eavesdropping attack against Ekert’s protocol based on Wigner’s inequality

Fabio Antonio Bovino, A.M. Colla, Giuseppe Castagnoli +3 more

We experimentally implemented an eavesdropping attack against the Ekert protocol for quantum key distribution based on the Wigner inequality. We demonstrate a serious lack of security of this protocol when the eavesdropper gains total control of the source. In addition we tested a modified Wigner inequality which should guarantee a secure quantum key distribution.

arXiv:quant-ph/0308030•Physical Review A•Sep 29, 2003•2 citations
We report on a complete free-space field implementation of a modified Ekert protocol for quantum key distribution using entangled photon pairs. For each photon pair we perform a random choice between key generation and a Bell inequality. The amount of violation is used to determine the possible knowledge of an eavesdropper to ensure security of the distributed final key.
Summary form only given. Quantum cryptography uses single photons to allow secure distribution of secret key material to sender and receiver, without the possibility of an undetected eavesdropper. In the protocol suggested by Ekert, each photon of a quantum-mechanically entangled pair is sent to the sender and receiver, who randomly measure the polarization in various bases. If the bases are the same, then sender and receiver will have completely correlated measurement results, which become the shared secret key. Other combinations of measurements are used to test Bell's inequalities, which limit the possible correlations achievable with any local realistic theory. The presence of an intermediate eavesdropper can be readily detected by an inability to violate Bell's inequality. Using the polarization-entangled photon pairs from a novel spontaneous parametric down-conversion source, we have experimentally implemented. Ekert's proposal.
In this paper we prove both theoretically and experimentally the insecurity of the Ekert’s protocol for quantum-key distribution when based on the Wigner inequality when entangled photon pairs are used as source. The security proof of the Eckert’s protocol based on Wigner’s inequality consists in verifying the violation of W ≥ 0 (which corresponds to local-realistic theories). We highlight that a violation of the Wigner’s inequality occurs when Eve controls the two quantum channels. We give the theoretical motivation for this result and we perform an experiment proving this weakness, by realizing the condition of Eve gaining total control of the source of photon pairs. In addition we calculate the modified version of this inequality which guarantees safe quantum-key distribution, thus proving it experimentally.
Today, perhaps more than ever before, the security of information and communication is increasingly important. The cryptographic protocols used in classical cryptography are based on mathematical algorithms and can be breached. On the other hand, the laws of quantum physics enable quantum key distribution (QKD) and it is possible to achieve absolute security of communication based on the fundamental laws of nature. Anyone who would eavesdrop QKD-based communication must perform a measurement, which implies an impact on the system that can be detected by the sender and receiver. In this paper, we present a brief overview of QKD implementations and our experimental setup for generation of quantum key. Using this setup, we measured violation of the Bell's inequality of 114 standard deviations from the classical boundary, which confirms the non-local behavior of the entangled photon pairs. One can also use this source to create hybrid connections in combination with both optical fibers and free space.
We report on the progress of our real-time entanglement based free-space quantum key distribution (QKD) system which uses polarization entangled photon pairs sent over a variety of free-space optical telescope links to distribute the key. An experiment with one photon from each pair sent over a 1,325 m long free-space link and the other photon detected locally next to the source is described. The system performs the complete QKD protocol including all error correction and privacy amplification algorithms. Over the course of 6.5 hours of communication at night an average raw key rate of 1,398 bits/s with an average quantum bit error rate (QBER) of 4.58% was observed producing an average final key rate of 244 bits/s. We also performed a Bell inequality experiment over two free-space links of 435 m and 1,325 m respectively, producing a total separation of 1,575 m between the two detectors in the experiment. During the Bell inequality experiment we observed an average Bell parameter of 2.51 ± 0.11.