Dynamic Access Control in a Concurrent Object Calculus

We develop a variant of Gordon and Hankin’s concurrent object calculus with support for flexible access control on methods. We investigate safe administration and access of shared resources in the resulting language. Specifically, we show a static type system that guarantees safe manipulation of objects with respect to dynamic specifications, where such specifications are enforced via access changes on the underlying methods at runtime. By labeling types with secrecy groups, we show that well-typed systems preserve their secrets amidst dynamic access control and untrusted environments.