Improved Bell–LaPadula Model With Break the Glass Mechanism

The Bell–LaPadula (BLP) model is a widely used access control model for the multilevel security system. The researchers proposed many modified BLP models to express privileges that cannot be expressed by the BLP model. However, these models are not compatible with the BLP model, leading to the transportation cost-prohibitive and difficult to be practically applied. In this article, an improved BLP model incorporated the break the glass (BTG) mechanism is proposed to overcome the limitations of the standard BLP and other modified BLP models. The improved model inherits some of the advantages of BTG, such as policy dynamic modification and fine-grained access control, which gives it wide availability. Additionally, in the implementation, BTG is used as an independent function attached to the original BLP; the proposed BLP model can be easily implemented in systems where BLP models have been implemented. The results of the analysis and simulations showed that the proposed BLP model improves the ability of expressing policy of BLP and achieves fine-grained access control without compromise in security. Compared with other modified BLP models, the proposed BLP model could express policy more effectively and is compatible with the original BLP model.