Quantum broadcast communication and authentication protocol with a quantum one-time pad

A quantum broadcast communication and authentication protocol with a quantum one-time pad based on the Greenberger-Horne-Zeilinger state is proposed. A binary string is used to express the identity of the receiver, which is encoded as a single sequence of photons. The encoded photon sequence acts as a detection sequence and implements au- thentication. An XOR operation serves as a one-time pad and is used to ensure the security of the protocol. The binary string is reused even in a noisy channel and proves to be unconditionally secure. In contrast with the protocols proposed by Wang et al. [Chin. Phys. 16 1868 （2007）] and Yang et al. [Chin. Phys. B 19 070304 （2010）], the protocol in this study implements the identity authentication with a reusable binary string; no hash function or local unitary operation is used. The protocol in this study is also easier to implement and highly efficient without losing security.