We present a modified version of the Chinese Wall model. Especially, we make some investigations on the indirect information flow induced by the write access. In the original Brewer-Nash model the write permission is very restricted. There a subject can get write access to one object only and only during early states of the system. We change this rule and introduce a dynamic concept of the “conflict of interest relation”. Thus, we prevent an indirect information flow by building more Chinese Walls. Finally, we prove that the system is “conflict secure”, i.e. a subject can never get sensitive information from two or more objects which are in conflict of interest to each other.
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