Quantum secure direct communication with χ -type entangled states

Abstract

In this paper, a quantum secure direct communication protocol with χ -type entangled states / χ00 3214 is proposed. We analyze the security of this protocol and prove that it is secure in ideal conditions. Then, an alternative way is presented to ensure the security of this protocol in a noisy channel. Moreover, this protocol utilizes quantum superdense coding to achieve a high intrinsic efficiency and source capacity. The practical implementation of this protocol is also discussed. © 2008 The American Physical Society.