Efficient Many-to-One and One-to-Many Multiparty Quantum Secure Direct Dommunication with Authentication

In the multiparty communication, there are two types of Communication modes: the many-to-one mode and the one-to-many mode. In this paper, two efficient authenticated multiparty quantum secure direct communication protocols are presented by using GHZ states and dense coding, one is used for the many-to-one communication, and the other is suitable to the one-to-many communication. Analysis shows these protocols are secure against outer Evepsilas attacks and inner anticipators´ attacks (including Trent´s attacks), and show more efficiency on message transmission and the repeated use of secrete identity.