Information Flow Control in the Fog Computing Model Based on a Component Degree Concept

The FC (Fog Computing) model is discussed to implement the IoT (Internet of Things). Here, it is significant to protect fog nodes and devices from malicious accesses since the both are only supported with poor computation resources. The CBAC (Capability-Based Access Control) model is useful because each node can just check a capability token carried with an access request. Sensor data is obtained from a device and stored in another device by an authorized subjects who are granted tokens. However, even unauthorized subjects get the data from another device, i.e. illegal information flow. In the FC model, nodes receive sensor data from devices and send processed data to another nodes. In addition to devices, we have to prevent illegal information flow among nodes. Since sensor data for devices is processed and new data is generated by nodes, it is critical to discuss how much sensor data is included in data sent by nodes. We discuss a concept of component degree of each data which nodes exchange. By taking advantage of the concept, we newly propose an RR (Request Rejection) protocol for preventing illegal information flow among nodes. In the evaluation, we show the ratio of requests rejected to all the requests of nodes in the RR protocol.