The conflict of interest relation defined in BN Chinese wall model was usually utilized to divide the resources into different access regions.Unfortunately

the Chinese wall model gave much constraint on write permission that the access regions need to be predetermined and divided statically.A modified version of Chinese wall model was proposed to solve this problem.Through establishing dynamic alliance to extend the conflict of interest relation

the objects of different conflict classes could be dynamically divided into different access regions.Finally

a theory was verified that the modified version of Chinese wall model could achieve the same security goal as BN Chinese wall model.The analysis shows that the model can be applied in covert flows confinement in virtual machine system.