SCoTMan: A Scalable Smart Contract for Trust Management in Social IoT With Real-World Constraints

The Internet of Things (IoT) plays a crucial role in our daily lives. Many objects are being equipped with electronic components in order to facilitate their interconnection and integration with the Internet. Due to the growing usage of IoT devices and generated data, to ensure the reliability of the network, it is necessary to utilize scalable and effective trust management systems. This study introduces the SCoTMan model, which integrates social interactions with the capability of smart contracts for effective trust management in Social IoT (SIoT). Blockchain can enhance trust management protocols by providing a global view of data and improving the propagation of trust values. Implementing trust management algorithms in traditional decentralized architectures can be challenging, but using smart contracts can provide an efficient solution. We implemented the model on the Hyperledger Fabric platform and performed a comprehensive assessment. The model efficiently performs indirect trust computations by choosing optimized counselors and minimizing storage requirements. Multiple experiments have been carried out to assess and validate the efficiency of the model in functionality metrics such as trust convergence and success rate, as well as non-functional metrics like transaction delay, computation and communication overhead, and memory usage. We also conducted a comparative analysis to emphasize the method's advantages over existing approaches in the literature. We introduced the Total Storage Cost metric for better comparison. The results show substantial improvements in trust convergence under limited Total Storage Cost. The proposed method demonstrates that it is possible to establish scalable trust management in the SIoT by utilizing smart contracts and social metrics.