Trust management in social Internet of Things: A taxonomy, open issues, and challenges

Internet of Things (IoT) is an emerging area in which billions of smart objects are interconnected with each other using Internet for data and resource sharing. These smart objects are generally used to sense various parameters such as temperature, motion of objects, and occupancy from the environment where these are deployed, the values of which are transmitted to the nearest access points to taken intelligent decisions. However, with an increased penetration of smart objects in our daily life, these objects may also participate in social events using machine-to-machine or human-to-machine interactions and are called as Social Objects. This new paradigm of interaction among social objects is referred to as Social loT (SloT). As these objects communicate with each other using an open channel, i.e., Internet, so security and privacy along with integrity of messages always remain a concern. Motivated from the aforementioend issues, in this paper, we provide an elaborated view of trust management among these objects with a focus on SIoT by comparing different existing trust management schemes based on the trust management process, parameters chosen for trust evaluation, characteristics of trust functions and objectives achieved by them. Moreover, we also discuss various challenges such as use of social behavior specific trust evaluation metrics and type of relationships between objects in SIoT with respect to trust management. Thus, the analysis provided in this paper provides insights to the readers for applicability of trust management scheme in SIoT environment keeping in of various challenges and constraints.