Synchronization Protocols to Prevent Illegal Information Flow in Role-Based Access Control Systems

In information systems, data in an object may illegally flow into another object if transactions manipulate the objects. In our previous studies, the role-based synchronization (RBS) and object-based synchronization (OBS) protocols are discussed to present illegal information flow in the role-based access control (RBAC) model. Illegal read operations mean read operations which might imply illegal information flow. Transactions which issue illegal read operations are aborted. In this paper, we consider a unique object whose data is not allowed to flow to another object. An illegal write is defined to be a write operation which is issued after reading a unique object or illegally reading an object in a transaction. Each transaction reads any object but is aborted if the transaction illegally writes an object. Synchronization protocol WA-RBS and WA-OBS are discussed based on abortion of transaction issuing illegal write operations.