Managing information flows on discretionary access control models

In 1989, Brewer and Nash (BN) presented a fascinating idea, called Chinese wall security policy model, for commercial security. Their idea was based on the analysis of the notion, conflict of interest binary relation (CIR). Unfortunately, their formalization did not fully catch the appropriate properties of CIR. In this paper, we present a theory based on granulation that has captured the essence of BN´s intuitive idea. The results are more than the Chinese wall models: malicious Trojan horses in certain DAC model (discretionary access control) can be controlled or confined.