A calculus for modeling floating authorizations

Abstract

Controlling resource usage in distributed systems is a challenging task given the dynamics involved in access granting. Consider, e.g., the setting of floating licenses where access can be granted if the request originates in a licensed domain and if the number of active users is within the license limits. Access granting in such scenarios is given in terms of floating authorizations, addressed in this paper as first class entities of a process calculus model, encompassing the notions of domain, accounting and delegation. We present the operational semantics of the model in two equivalent alternative ways, each informing on the specific nature of authorizations. We also introduce a typing discipline to single out systems that never get stuck due to lacking authorizations, addressing configurations where authorization assignment is not statically prescribed in the system specification.