Quantum Cryptography Using Coherent State

Quantum cryptography is a new way to distribute keys, which can detect any eavesdropping. Quantum cryptography using single particle or weak light pulse has been discussed in some early papers, but it is difficult to transmit such single particle or weak light pulse. We propose a scheme of quantum key distribution using coherent State |α > and |α + Δα>. We also discuss its feasibility and security, and give an experimental realization of this scheme.