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:quant-ph/0302196 · Physical Review A

Modified Wigner inequality for secure quantum-key distribution

Stefania Castelletto, Ivo Pietro Degiovanni, Maria Luisa Rastello

Published Apr 30, 2003• 8 citations
arXivHTMLPDF

Abstract

In this paper, we discuss the insecurity with present implementations of the Ekert protocol for quantum-key distribution based on the Wigner inequality. We propose a modified version of this inequality which guarantees safe quantum-key distribution.
DOI
10.1103/physreva.67.044303

Related papers

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

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

Quantum correlation bounds for optimization of quantum-information experiments: The Wigner inequality case

Fabio Antonio Bovino, Ivo Pietro Degiovanni

Violation of modified Wigner inequality in a binary bipartite quantum system allows the discrimination between the quantum world and the classical local-realistic one, and also ensures the security of Ekert-type quantum key distribution protocol. In this paper we study both theoretically and experimentally the bounds of quantum correlation associated to the modified Wigner's inequality finding the optimal experimental configuration for its maximal violation. We also extend this analysis to the implementation of Ekert's protocol.

arXiv:0802.2256•Physical Review A•May 13, 2008•5 citations

QUANTUM CORRELATION BOUNDS FOR WIGNER'S INEQUALITY GENERALIZED PARAMETRIZATION

Ivo Pietro Degiovanni, Fabio Antonio Bovino

Bounds of quantum correlation associated to the modified Wigner inequality according to most general possible parametrization are investigated, finding the configuration for its maximal violation. Furthermore we extended this analysis to the implementation of the Ekert's protocol for quantum key distribution based on Wigner

International Journal of Quantum Information•Jan 1, 2009•0 citations

A qutrit quantum key distribution protocol using Bell inequalities with larger violation capabilities

Zoé Amblard, François Arnault

The Ekert quantum key distribution protocol [1] uses pairs of entangled qubits and performs checks based on a Bell inequality to detect eavesdropping. The 3DEB protocol [2] uses instead pairs of entangled qutrits to achieve better noise resistance than the Ekert protocol. It performs checks based on a Bell inequality for qutrits named CHSH-3 and found in [3, 4]. In this paper, we present a new protocol, which also uses pairs of entangled qutrits, but gaining advantage of a Bell inequality which achieves better noise resistance than the one used in 3DEB. The latter inequality is called here hCHSH-3 and was discovered in [5]. For each party, the hCHSH-3 inequality involves four observables already used in CHSH-3 but also two products of observables which do not commute. We explain how the parties can measure the observables corresponding to these products and thus are able to check the violation of hCHSH-3. In the presence of noise, this violation guarantees the security against a local Trojan horse attack. We also designed a version of our protocol which is secure against individual attacks.

Quantum Information and Computation•Nov 1, 2015•0 citations

Quantum Key Distribution: Basic Protocols and Threats

Maria E. Sabani, Ilias Κ. Savvas, Dimitrios Poulakis +1 more

The last decade, the evolution in quantum computing has been enormous and real and reliable quantum computers are being developed quickly. One of the consequences of the upcoming quantum era is to make key distribution protocols insecure, as most of them are based on discrete algorithm problems. On the other hand, quantum computing provides a powerful and prominent tool for the safe transmission of information and cryptographic schemes and many of them have already been proposed. In this work, we discuss about quantum cryptography and we present certain quantum key distribution protocols. We also discuss about ‘potential attacks that can be performed against the quantum cryptographic schemes which are based on quantum system’s imperfections and loopholes.

Panhellenic Conference on Informatics•Nov 25, 2022•21 citations
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.
Violation of modified Wigner inequality in a binary bipartite quantum system allows the discrimination between the quantum world and the classical local-realistic one, and also ensures the security of Ekert-type quantum key distribution protocol. In this paper we study both theoretically and experimentally the bounds of quantum correlation associated to the modified Wigner's inequality finding the optimal experimental configuration for its maximal violation. We also extend this analysis to the implementation of Ekert's protocol.
The Ekert quantum key distribution protocol [1] uses pairs of entangled qubits and performs checks based on a Bell inequality to detect eavesdropping. The 3DEB protocol [2] uses instead pairs of entangled qutrits to achieve better noise resistance than the Ekert protocol. It performs checks based on a Bell inequality for qutrits named CHSH-3 and found in [3, 4]. In this paper, we present a new protocol, which also uses pairs of entangled qutrits, but gaining advantage of a Bell inequality which achieves better noise resistance than the one used in 3DEB. The latter inequality is called here hCHSH-3 and was discovered in [5]. For each party, the hCHSH-3 inequality involves four observables already used in CHSH-3 but also two products of observables which do not commute. We explain how the parties can measure the observables corresponding to these products and thus are able to check the violation of hCHSH-3. In the presence of noise, this violation guarantees the security against a local Trojan horse attack. We also designed a version of our protocol which is secure against individual attacks.
The last decade, the evolution in quantum computing has been enormous and real and reliable quantum computers are being developed quickly. One of the consequences of the upcoming quantum era is to make key distribution protocols insecure, as most of them are based on discrete algorithm problems. On the other hand, quantum computing provides a powerful and prominent tool for the safe transmission of information and cryptographic schemes and many of them have already been proposed. In this work, we discuss about quantum cryptography and we present certain quantum key distribution protocols. We also discuss about ‘potential attacks that can be performed against the quantum cryptographic schemes which are based on quantum system’s imperfections and loopholes.