Towards a Policy Language for Humans and Computers

A policy is a statement that an action is permitted or forbidden if certain conditions hold. We introduce a language for reasoning about policies called Rosetta. What makes Rosetta different from existing approaches is that its syntax is essentially a fragment of English. The language also has formal semantics, and we can prove whether a permission follows from a set of Rosetta policies in polynomial time. These features make it fairly easy for policy language developers to provide translations between their languages and ours. As a result, policy writers and (human) readers can create and access policies via the interface of their choice; these policies can be translated to Rosetta; and once in Rosetta can be translated to an appropriate language for enforcement.