We present an extension to a d-ary alphabet of a recently proposed deterministic quantum key distribution protocol. It relies on the use of mutually unbiased bases in prime power dimension d, for which we provide an explicit expression. Then, by considering a powerful individual attack, we show that the security of the protocol is maximal for d=3.
@article{arxiv.0802.4160,
title = {Deterministic Quantum Distribution of a d-ary key},
author = {Anita Eusebi and Stefano Mancini},
journal= {arXiv preprint arXiv:0802.4160},
year = {2009}
}