Enforcing Security Policies via Types

Security is a key issue for distributed systems/applications with code mobility, like, e.g., e-commerce and on-line bank transactions. In a scenario with code mobility, traditional solutions based on cryptography cannot deal with all security issues and additional mechanisms are necessary. In this paper, we present a flexible and expressive type system for security for a calculus of distributed and mobile processes. The type system has been designed to supply real systems security features, like the assignment of different privileges to users over different data/resources. Type soundness is guaranteed by using a combination of static and dynamic checks, thus enforcing specific security policies on the use of resources. The usefulness of our approach is shown by modeling the simplified behaviour of a bank account management system.