Authors: Radha Jagadeesan ; Alan Jeffrey ; Corin Pitcher ; James Riely

We study mechanisms that permit program components to express role constraints on clients, focusing on programmatic security mechanisms, which permit access controls to be expressed, in situ, as part of the code realizing basic functionality. In this setting, two questions immediately arise: (1) The user of a component faces the issue of safety: is a particular role sufficient to use the component? (2) The component designer faces the dual issue of protection: is a particular role demanded in all execution paths of the component? We provide a formal calculus and static analysis to answer both questions.