High-Efficient Deterministic Secure Quantum Communication Based on Four-Qubit Cluster Sate

A novel high-efficient deterministic secure quantum communication protocol with four-qubit cluster states is proposed. Compared with YUAN Hao’s scheme [YUAN Hao et al 2008 Commun. Theor. Phys. 50 1105], our scheme has many advantages. In our scheme, the secret messages can be encoded on the four-qubit cluster states by employing eight two-particle unitary operations. By making Bell measurement and two-particle measurement, the two legitimate users can transmit the secret messages after exchanging some additional classical information. It has a high-efficient as each cluster state can carry three bits of secret information. Analysis shows it is secure and feasibility. Furthermore, this protocol is feasible with present-day technique.