Authorization Policy Specification and Enforcement for Group-Centric Secure Information Sharing (Full Version)

In this paper, we propose a methodology for incremental security policy specification at varying levels of abstraction while maintaining strict equivalence with respect to authorization state. We specifically consider the recently proposed group-centric secure information sharing (g-SIS) domain. The current specification for g-SIS authorization policy is stateless in the sense that it solely focuses on specifying the precise conditions under which authorization can hold in the system while only considering the history of actions that have occurred. The stateless application policy has been specified using linear temporal logic. In this paper, we develop an enforceable specification that is stateful in the sense that it is defined using specific data structures that are maintained in each state so as to make authorization decisions. We show that the stateful specification is authorization equivalent to that of stateless. That is, in any state, authorization will hold in stateful if and only if it also holds in the stateless specification.