Affiliations: [a] Trifork, Aarhus, Denmark. E-mail: kkr@trifork.com | [b] BRICS, University of Aarhus, Denmark. E-mail: mn@brics.dk | [c] School of Electronics and Computer Science, University of Southampton, UK. E-mail: vs@ecs.soton.ac.uk
Abstract: Reputation systems are meta systems that record, aggregate and distribute information about principals' behaviour in distributed applications. Similarly, history-based access control systems make decisions based on programs' past security-sensitive actions. While the applications are distinct, the two types of systems are fundamentally making decisions based on information about the past behaviour of an entity. A logical policy-centric framework for such behaviour-based decision-making is presented. In the framework, principals specify policies which state precise requirements on the past behaviour of other principals that must be fulfilled in order for interaction to take place. The framework consists of a formal model of behaviour, based on event structures; a declarative logical language for specifying properties of past behaviour; and efficient dynamic algorithms for checking whether a particular behaviour satisfies a property from the language. It is shown how the framework can be extended in several ways, most notably to encompass parameterized events and quantification over parameters. In an extended application, it is illustrated how the framework can be applied for dynamic history-based access control for safe execution of unknown and untrusted programs.
Keywords: Reputation systems, history-based access control, trust management, dynamic model checking, event structures, linear temporal logic
