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Security and Communication Networks

A novel approach to build QKD relaying models

Quoc‐Cuong Le, Patrick Bellot

Published Sep 25, 2009• 0 citations
Publisher

Abstract

Abstract Quantum Key Distribution (QKD) is an unconditionally secure key‐agreement scheme that promises worthwhile applications. One most critical drawback of QKD is the limitation of the range. In this paper, we present a novel idea that can be useful in the development of new effective QKD relaying models. As an illustration, we introduce two new models that are based on the proposed idea, capable of securely extending the range of original QKD schemes by using untrusted relays. Copyright © 2009 John Wiley & Sons, Ltd.

DOI
10.1002/sec.139

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Abstract Quantum Key Distribution (QKD) is an unconditionally secure key‐agreement scheme that promises worthwhile applications. One most critical drawback of QKD is the limitation of the range. In this paper, we present a novel idea that can be useful in the development of new effective QKD relaying models. As an illustration, we introduce two new models that are based on the proposed idea, capable of securely extending the range of original QKD schemes by using untrusted relays. Copyright © 2009 John Wiley & Sons, Ltd.
We investigate Quantum Key Distribution (QKD) relaying models. Firstly, we propose a novel quasi-trusted QKD relaying model. The quasi-trusted relays are defined as follows: (i) being honest enough to correctly follow a given multi-party finite-time communication protocol; (ii) however, being under the monitoring of eavesdroppers. We develop a simple 3-party quasi-trusted model, called Quantum Quasi-Trusted Bridge (QQTB) model, to show that we could securely extend up to two times the limited range of single-photon based QKD schemes. We also develop the Quantum Quasi-Trusted Relay (QQTR) model to show that we could securely distribute QKD keys over arbitrarily long distances. The QQTR model requires EPR pair sources, but does not use entanglement swapping and entanglement purification schemes. Secondly, we show that our quasi-trusted models could be improved to become untrusted models in which the security is not compromised even though attackers have full controls over some relaying nodes. We call our two improved models the Quantum Untrusted Bridge (QUB) and Quantum Untrusted Relay (QUR) ones. The QUB model works on single photons and allows securely extend up to two times the limited QKD range. The QUR model works on entangled photons but does not use entanglement swapping and entanglement purification operations. This model allows securely transmit shared keys over arbitrarily long distances without dramatically decreasing the key rate of the original QKD schemes.
Secure communication makes the widespread use of telecommunication networks and services possible. With the constant progress of computing and mathematics, new cryptographic methods are being diligently developed. Quantum Key Distribution (QKD) is a promising technology that provides an Information-Theoretically Secure (ITS) solution to the secret-key agreement problem between two remote parties. QKD networks based on trusted relay nodes are built to provide service to a larger number of parties at arbitrary distances. They function as an add-on technology to traditional networks, generating, managing, distributing, and supplying ITS cryptographic keys. Since key resources are limited, integrating QKD network services into critical infrastructures necessitates effective key management. As a result, this article provides a comprehensive review of key management approaches for trusted-relay QKD networks. They are analyzed to facilitate the identification of potential strategies and accelerate the future development of QKD networks.
Quantum Key Distribution (QKD) is a technology that ensures, in theory, the inviolability of the transmitted key. However, some practical implementation problems remain open, especially on increasing the range of QKD's application. The objective of this thesis is to answer twocorrelated questions: (1) how to build large QKD networks, (2) how to secure QKD key relays. We have proposed, at the first stage, a model to ensure the security of key transmission in a large QKD network by using a stochastic routing. The effectiveness of this method is demonstrated by using percolation theory. In a second stage, we explored the safety of QKD relays and arrive to propose four new models to expand the range of QKD.
Quantum key distribution (QKD) technology can establish unconditional secure keys between two communicating parties. Although this technology has some inherent constraints, such as the distance and point-to-point mode limits, building a QKD network with multiple point-to-point QKD devices can overcome these constraints. Considering the development level of current technology, the trust relaying QKD network is the first choice to build a practical QKD network. However, the previous research didn’t address a routing method on the trust relaying QKD network in detail. This paper focuses on the routing issues, builds a model of the trust relaying QKD network for easily analysing and understanding this network, and proposes a dynamical routing scheme for this network. From the viewpoint of designing a dynamical routing scheme in classical network, the proposed scheme consists of three components: a Hello protocol helping share the network topology information, a routing algorithm to select a set of suitable paths and establish the routing table and a link state update mechanism helping keep the routing table newly. Experiments and evaluation demonstrates the validity and effectiveness of the proposed routing scheme.
Abstract A point‐to‐point quantum key distribution (QKD) system takes advantage of the laws of quantum physics to establish secret keys between two communicating parties. Compared to the classical methods, such as public‐key infrastructures, QKD offers unconditional security, which makes it attractive for very high security applications. However, this unprecedent level of security is mitigated by the inherent constraints of quantum communications, such as the limited rates and ranges of an individual point‐to‐point QKD link. A QKD network, which can be built by combining multiple point‐to‐point QKD devices, can alleviate the constraints and enable point‐to‐multi‐point key distribution based on QKD technology. The European project, secure communication based on quantum cryptography (SeCoQC) aims at deploying a prototype QKD network, which will be demonstrated in September 2008, by developing the architecture and the protocols, as well as the specific hardware for long‐range QKD networks. This paper discusses the important aspects of the architecture and the network layer protocols of the SeCoQC QKD network. Copyright © 2008 John Wiley & Sons, Ltd.