Abstract. Identifying and protecting the trusted computing base (TCB) of a system is an important task, which is typically performed by designing and enforcing a system security policy and verifying whether an existing policy satisfies security objectives. To efficiently support these, an intuitive and cognitive policy analysis mechanism is desired for policy designers or security administrators due to the high complexity of policy configurations in contemporary systems. In this paper, we present a graph-based policy analysis methodology to identify TCBs with the consideration of different system applications and services. Through identifying information flows violating the integrity protection of TCBs, we also propose resolving principles to using our developed graph-based policy analysis tool.