Traffic Reduction for Information Flow Control in the IoT

In the CBAC (Capability-Based Access Control) model for the IoT (Internet of Things), subjects are issued capability tokens, i.e. a set of access rights on objects in devices, by device owners. Objects are data resource in a device which are used to store sensor data and action data. Through manipulating objects of devices, data are exchanged among subjects and objects. Here, the illegal information flow and the late information flow occur and subjects can get data which the subjects are not allowed to get. In our previous studies, protocols are implemented to interrupt operations implying both illegal and late types of information flows. Here, the request processing time takes longer as the number of capability tokens whose signatures are verified in devices increases. Hence, an MRCTSD (Minimum Required Capability Token Selection for Devices) algorithm to reduce the number of capability tokens used is proposed. However, the more number of capability tokens are sent from subjects, the more complex the capability token selections are. Since the devices support just low processing power and smaller size of memory, it is important to avoid concentrating loads in devices. In this paper, MRCTSS (MRCTS for Subjects) algorithm where subjects selects minimum required capability tokens and sends them to devices is proposed. In the evaluation, it is shown that the size of a UDP datagram in a get access request is made smaller by the MRCTSS algorithm.