Qunits in Two Way Quantum Key Distribution

Works in two way deterministic quantum cryptography protocols using qubits and qutrits have seen the nontrivial generalization of the protocol to accommodate the use of all mutually unbiased bases (MUB). Here we consider the use of qunits (quantum systems of n dimensional Hilbert space) in a similar protocol and working with cases where the number of MUB is n +1 we show that n qunits are necessary to generalize the use of all available MUBs. We also provide a recipe that would allow for encoding with unitary efficiency.