FlexFlow: A Flexible Flow Control Policy Specification Framework

Flow control policies are important in data-flow, work-flow, transaction systems and software design. Previous work in this area concentrates either on modelling security aspects of information flow control or applying flow control policies in some specific application domain. These models permit either permissions or prohibitions for flows and normally are based on a specific meta-policy (usually the closed policy). We propose FlexFlow, a logic based flexible flow control framework to specify data-flow, work-flow and transaction systems policies that go beyond point-to-point flows. Both permissions and prohibitions are specifiable in FlexFlow and meta-policies such as permissions take precedence themselves can be specified over the meta-policy neutral policy specification environment of FlexFlow. We further show how to specify and prevent inter-flow conflicts such as those arising in role-based work-flow policies. Key Phrases: Flow control policy, Data flow, work flow, security policy, security constraints.