  We expand the recently discussed continuous-variable quantum key distribution
scheme of Heid and Luetkenhaus (2006) to qudits with a lossy but noiseless
quantum channel. Postselection methods are used. Secret key rates are
calculated in the presence of loss for the direct and the reverse
reconciliation method. In the case of reverse reconciliation the secret key
rate increases with higher dimensions, in the case of direct reconciliation the
result is reverse. Several ways of optimising the amplitude are discussed. In a
next step the used states are generalised to squeezed states. Again secret key
rates are calculated. The last part deals with the dual-homodyne detection
which replaces the single-homodyne measurement. Most results are analytical and
allow further treatments if the preparation symmetry stays unchanged.
