Abstract:
We discuss generalisations of quantum cryptographic protocols from
qubits to
qudits and analyse criteria for unconditional security of such
protocols.
To this aim we consider error correction using one-way and two-way
classical
communications, while focussing on protocols which can be reduced to
practically feasible prepare-and-measure schemes. We attempt to
provide upper
and lower bounds for the maximally tolerable error rates of these
protocols
using generic methods to determine such bounds.
