Trust Management in Internet of Things: Review, Analysis and Establishment of Evaluation Criteria

Within the complex Internet of Things (IoT) paradigm that things interact with each other as well as with human beings, one approach to provide security for smart network-based applications is to implement trust management systems.  Trust, in general, overlaps with concepts such as security, privacy and reliability. However, the high number of objects in IoT, along with its dynamic nature and existence of malicious entities, make IoT trust management quite challenging. These unique attributes rule out the application of previous best practices in IoT networks. In this paper, in addition to the analysis of direct, indirect and hybrid trust calculation algorithms, we introduce the relevant attacks and their countermeasures. Moreover, we study the methods for trust model evaluation and also, the effect of limited resources on the performance of trust calculation algorithms.  In short, we carry out a comparative survey in which IoT trust-related works are studied from four perspectives: (1) Trust calculation model, (2) Attack resistance, (3) The effect of resource limitation on the model performance, and (4) Trust management evaluation framework. Through this, we find the pros and cons of the existing algorithms and make a measure for IoT trust management systems. We provide some comparative tables to depict the discrepancies of the existing IoT trust models. One main contribution of this paper is to establish some quantitative metrics to evaluate the trust estimation models and reveal their strengths and deficiencies under different conditions.