Abstract: A new cross-domain authentication protocol model is developed on hypercube basis, where the structural features of hypercube support the reversible entity authentication between different trust domains. Compared with the conventional cross-domain authentication model, the proposed model is able to not only reduce the registration workload but also simplify the distribution and management of shared cipher keys among authentication servers. In addition, the model can avoid the network bottleneck and single-point collapse due to the authentication by a single authority. Analytical results showed that the protocol model is highly secure and reliable, thus enabling the server in application to access and control so as to ensure the network security.