Blockchain-Based Reputation and Trust Management for Smart Grids, Healthcare, and Transportation: A Review

In a smart city environment, various intelligent devices, applications, and digital networks collaborate to provide technological solutions for the public good. The exponential data generated from intelligent interactions among stakeholders within the smart city ecosystem raises concerns regarding security and privacy. Maintaining data openness while safeguarding it against social engineering attacks, network breaches, and data masking threats is paramount to achieving resilience. Blockchain technology has demonstrated great promise in addressing these challenges due to its decentralized, consistent, and tamper-proof nature. Our paper explores how blockchain can address the challenges of integrity, security, and privacy in smart city operations. Despite significant research efforts, the subject remains in need of a comprehensive survey. Consequently, we conduct a study on state-of-the-art blockchain-based reputation and trust management methods within the three fundamental components of a smart city: energy, healthcare, and transportation. The trust and reputation mechanisms are analyzed to identify their strengths and limitations. The investigation reveals that the existing trust schemes are resource-constrained and encounter scalability limitations, high energy consumption, and incompatibility with existing systems.