  This letter proposes a novel key distribution protocol with no key exchange
in advance, which is secure as the BB84 quantum key distribution protocol. Our
protocol utilizes a photon in superposition state for single-bit data
transmission instead of a classical electrical/optical signal. The security of
this protocol relies on the fact, that the arbitrary quantum state cannot be
cloned, known as the no-cloning theorem. This protocol can be implemented with
current technologies.
