INFORMATION-LEAKAGE-FREE QUANTUM DIALOGUE VIA GREENBERGER-HORNE-ZEILINGER STATES

Secure communication in general and secure dialogue in particular are highly demanded, especially in the current information exploding era. Here we are concerned with secure dialogue. Because any dialogue conducted merely by classical means is fully eavesdropped without traces left behind, quantum version of dialogue, the so-called quantum dialogue, offers a promising solution to the security problem. The security desired does not simply focus on the exchanged information but also on their classical correlations, i.e., a quantum dialogue protocol should be protected from both information theft and information leakage. Such a secure quantum dialogue protocol is proposed in this paper employing Greenberger-Horne-Zeilinger states as the quantum channel. The above-mentioned requirement for security is achieved in message rounds by using extra random bits for the encoding/decoding processes combined with two kinds of control rounds which are designed to detect eavesdropping, if any.