  This paper presents a quantum mechanical version of the piggy-bank
cryptography protocol. The basic piggybank cryptography idea is to use two
communications: one with the encrypted message, and the other regarding the
encryption transformation which the receiver must decipher first. In the
quantum mechanical version of the protocol, the encrypting unitary
transformation information is sent separately but just deciphering it is not
enough to break the system. The proposed quantum protocol consists of two
stages.
