title: Optimal eavesdropping in cryptography with three-dimensional quantum states.
abstract: We study optimal eavesdropping in quantum cryptography with three-dimensional systems, and show that this scheme is more secure against symmetric attacks than protocols using two-dimensional states. We generalize the according eavesdropping transformation to arbitrary dimensions, and discuss the connection with optimal quantum cloning.
authors.affiliation: Institut für Theoretische Physik, Universität Hannover, 30167 Hannover, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Bruss
authors.forename: C
authors.initials: C
authors.lastname: Macchiavello