Multi-user Quantum Cryptography

Simon J. D. Phoenix, Stephen Mark Barnett, Paul D. Townsend +1 more

Quantum cryptography has been shown to be an effective technology for the secure distribution of keys on point-to-point optical links. We show how the existing techniques can be extended to allow multi-user secure key distribution on optical networks. We demonstrate that using network configurations typical of those found in passive optical network architectures any of the current quantum key distribution protocols can be adapted to implement secure key distribution from any user to any other user. An important feature of these adapted protocols is that the broadcaster, or service provider on the network, does not have to be trusted by the two users who wish to establish a key.

Charles H. Bennett, Gilles Brassard A, ARTUR K. EKERT

Bing C. Wang, Patrick D. Kumavor, Susanne F. Yelin +1 more

Quantum cryptography applies the uncertainty principle and the no-cloning theorem of quantum mechanics to provide ultra-secure encryption key distribution between two parties. Present quantum cryptography technologies provide encryption key distribution between two parties. However, practical implementations encryption key distribution schemes require establishing secure quantum communications amongst multiple users. In this talk, we survey some of the state of the art quantum encryption deployment in communication networks. We will also discuss some common topologies that are being considered for multi-user quantum encryption networks. The performance of the multi-user quantum key distribution systems is then compared for four different optical network topologies: the Sagnac-based fiber ring, the wavelength routed, the passive star and the bus network. Their performances are compared and analyzed using quantum bit error rate analysis.

Paul Wallich

Haiqiang Ma, Jian-Hui Yang, Kejin Wei +2 more

We propose a modified ‘‘Plug and play’’ systems, which skillfully makes use of automatic alignment of the photon polarization states in optical fiber and a multi-users quantum key distribution system based on the aforementioned systems.

Jean-Louis Basdevant, Jean Dalibard