We study optimal eavesdropping in quantum cryptography with three-dimensional systems, and show that this scheme is more secure than protocols using two-dimensional states. We generalize the according eavesdropping transformation to arbitrary dimensions, and discuss the connection with optimal quantum cloning.
@article{arxiv.quant-ph/0106126,
title = {Optimal eavesdropping in cryptography with three-dimensional quantum states},
author = {D. Bruss and C. Macchiavello},
journal= {arXiv preprint arXiv:quant-ph/0106126},
year = {2009}
}