MULTIUSER QUANTUM CRYPTOGRAPHY ON OPTICAL NETWORKS

Quantum cryptography has been shown to be an effective technology for the secure distribution of keys on point-to-point optical links. We sh ow how the existing techniques can be extended to allow multi-user sec ure key distribution on optical networks. We demonstrate that using ne twork configurations typical of those found in passive optical network architectures any of the current quantum key distribution protocols c an be adapted to implement secure key distribution from any user to an y 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.