A Multilevel Security Model for Private Cloud

Towards data leak caused by misoperation and malicious inside users, we proposed a multilevel security model based on Bell-lapadula (BLP) model. In our model each subject was assigned with a security level. Subjects can read objects only when their security levels are not less than objects' security levels, and subjects can write objects only when their security levels are not more than objects' security levels. The current security level in our model can be dynamically changed when users read sensitive data, since users can access data with different security levels in private cloud. Our model use mandatory access control method to control user's operation and can guarantee that users can not leak sensitive data after they read them. Our model can be proved secure by mathematical method, and we implemented a prototype system of our model and the experimental results show that it is secure.