Optimal dimensionality for quantum cryptography

D. B. Horoshko, S. Ya. Kilin

Published 2002-03-19Version 1

We perform a comparison of two protocols for generating a cryptographic key composed from d-valued symbols: one exploiting a string of independent qubits and another one utilizing d-level systems prepared in states belonging to d+1 mutually unbiased bases. We show that the protocol based on qubits is optimal for quantum cryptography, since it provides higher security and higher key generation rate.