Logic-Based Domain-Aware Session Types

Software services and governing communication protocols are increasingly domain-aware. Domains can have multiple interpretations, such as the principals on whose behalf processes act or the location at which parties reside. Domains impact protocol compliance and access control, two central issues to overall functionality and correctness in distributed systems. This paper proposes a session-typed process framework for domain-aware communication-centric systems based on a CurryHoward interpretation of linear logic, here augmented with nominals from hybrid logic indicating domains. These nominals are explicit in the process expressions and govern domain migration, subject to a parametric accessibility relation familiar from the Kripke semantics for modal logic. Flexible access relationships among domains can be elegantly defined and statically enforced. The framework can also account for scenarios in which domain information is discovered only at runtime. Due to the logical origins of our systems, well-typed processes enjoy session fidelity, global progress, and termination. Moreover, well-typed processes always respect the accessibility relation and satisfy a form of domain parametricity, two properties crucial to show that domain-related properties of concrete programs are satisfied.