Blockchain-Enabled IoT Architectures for Secure Smart Cities

The rapid digitalization of urban environments has accelerated the adoption of smart city systems, with the Internet of Things (IoT) serving as a core enabler of real-time monitoring, automation, and data-driven services.Despite its advantages, IoT-based smart city infrastructure faces critical security and reliability challenges, including data breaches, device tampering, unauthorized access, and limited computational protection.These vulnerabilities compromise the robustness, trustworthiness, and sustainability of smart city deployments, underscoring the necessity for secure and decentralized system architectures.This study explores the integration of Blockchain and IoT as a transformative pathway toward secure and reliable smart city systems.Through a focused literature review, case analysis, and conceptual modeling, we demonstrate that Blockchain enhances IoT security by enabling distributed trust, token-based authentication, and resilient data integrity while reducing single points of failure.Although challenges related to scalability, energy consumption, interoperability, and regulation persist, the lightweight consensus mechanisms and AIassisted frameworks continue to further improve system efficiency and scalability, and Blockchain-IoT integration offers a promising foundation for nextgeneration secure smart city infrastructure.