The Internet of Things (IoT) has enabled the connection of various smart devices that can communicate with each other and with cloud services. However, the centralized nature of cloud services and the increasing amount of sensitive data being transmitted by IoT devices raise concerns about security and privacy. Fog computing, which brings computation and storage closer to the edge of the network, has been proposed as a solution to address these issues. In a blockchain-based secure fog-cloud architecture for IoT, fog computing nodes and cloud servers collaborate to provide a secure and efficient system. The blockchain provides an immutable ledger for recording transactions and enables secure and transparent communication between different nodes in the network. The fog nodes act as gateways for IoT devices to communicate with the cloud services while also providing computational power and storage capabilities. The architecture includes several layers of security measures, including secure bootstrapping, data encryption, access control, and blockchain-based consensus mechanisms. The secure bootstrapping process ensures that only authorized devices can access the network. Data encryption ensures that data is protected both in transit and at rest. Access control mechanisms restrict access to sensitive data based on user roles and permissions. The blockchain-based consensus mechanism ensures that all nodes in the network agree on the validity of transactions and that no malicious actors can manipulate the data. The consensus mechanism also ensures that data is tamper-proof and provides an audit trail for all transactions. Overall, a blockchain-based secure fog-cloud architecture for IoT can provide a secure and efficient system for handling sensitive data while enabling the benefits of cloud services and IoT devices. It can also provide transparency and accountability, which are essential for building trust in the system.

Secure Internet of Things (IoT) , Fog Computing , Cloud Computing , Blockchain Model, Distributed Ledger Technology (DLT) , Decentralized Security , Smart Contracts.