Single-Photon Multiparty Quantum Cryptographic Protocols With Collective Detection

In order to reduce the requirements on quantum devices, Shih proposed two three-party quantum key distribution (QKD) protocols . However, Gao presented a simple and effective attack strategy (i.e., dense-coding attack) upon the two protocols . In this paper, we make a deep analysis on the reason why Shih three-party QKD protocols are not secure. Meanwhile, we improve the three-party QKD protocols so that they can resist the Gao attack. On this basis, we present a formalism of single-photon multiparty quantum cryptographic protocol with collective detection. In this formalism, single photons are employed and all participants, except one whom we call as the center, only need to have the ability to perform single qubit unitary operations. Considering the expensive quantum devices, this formalism is low-priced which means it is easy to realize. Further more, this formalism can be widely used in various quantum cryptographic protocols, such as quantum secret sharing, quantum coin flipping, and quantum secure direct communication.