Enhancing security in quantum cryptography

Quantum Key Distribution was named as one of the top ten emerging technologies by Technology Review Journal in 2003 in their annual edition. The growth in quantum cryptography since the beginning of the millennium has been expedited by new theories and ideas. The introduction of practical quantum cryptosystems offered by USA based company MagiQTech and its European rival idQuantique has changed the face of cryptography. With active experimental research in USA, Europe, Japan and Singapore, the scope of quantum cryptography seems to be growing daily. When Bennett and Brassard proposed their BB84 protocol in Bangalore in 1984, no one would have guessed the quantum revolution they had launched. Since then, new protocols have been proposed and new theories developed, but BB84 remains the simplest and probably the easiest to implement. Now that the practical implementation of basic quantum cryptography has been achieved, one can be almost certain that new protocols will sooner or later be tested for the efficiency they could provide. We have developed a Classical Authentication Aided (CAA) protocol, which merges the classical authentication policies with quantum transmission to make it even more secure. With the complexities of the authentication policies and the bit to qubit conversion, our system becomes a complex one. We also discuss the possibilities of free space quantum transmission of the protocol instead of only through optical fiber