Efficient Quantum Secure Direct Communication with Authentication

Abstract

Two protocols of quantum direct communication with authentication [Phys. Rev.\nA 73, 042305(2006)] were recently indicated to be insecure against the\nauthenticator Trent's attacks [Phys. Rev. A 75, 026301(2007)]. We present two\nefficient protocols by using four Pauli operations, which are secure against\ninner Trent's attacks as well as outer Eve's attacks. Finally, we generalize\nthem to multiparty quantum direction communication.\n