Controlling information flows to prevent information leakage within an application is essential. According to the maturity of object-oriented techniques, many models were developed for the control in object-oriented systems. Since objects may be dynamically instantiated during program execution, controlling information flows among objects is difficult. Our research revealed that association is useful in the control. We developed an association-based information flow control model for object-oriented systems. It precisely controls information flows among objects through associations and constraints. It also offers features such as controlling method invocation through argument sensitivity, allowing declassification, allowing purpose-oriented method invocation, and precisely controlling write access. This paper proposes the model and the implementation of the model, which is composed of the language AbFlow (association-based flow) and its supporting environment.
