A blockchain-enabled edge–cloud framework for secure, scalable IoT data sharing

Hybrid edge exchange chain (HybrEx-chain) is a blockchain-enabled hybrid edge–cloud framework for secure and scalable data sharing in internet of things (IoT) networks. The framework combines edge computing for fast local pro cessing with cloud computing for resource-intensive tasks and global coordina tion. Proxy re-encryption (PRE) based on elliptic curve cryptography (ECC) protects data end-to-end and enables confidential data sharing without exposure of plaintext at intermediate nodes. A hierarchical consensus mechanism inte grates delegated practical byzantine fault tolerance (d-PBFT) at edge clusters with delegated proof of stake (DPoS) at the cloud layer to improve scalability and reduce consensus delay. Smart contracts on the blockchain manage time based re-encryption key rotation and enforce adaptive access policies to support automated security management. The framework is evaluated in a simulation environment based on Urban Deployment, Industrial IoT, and Smart Healthcare scenarios. The results show lower latency (140.5–155 ms), higher throughput (1150–1255 transactions per second), high scalability (up to 99%), and reduced consensus time compared with existing PRE-based frameworks FE-PRE and PREA. By combining edge responsiveness, cloud-level scalability, and cryptographic key management, HybrEx-chain provides an effective approach for secure and efficient IoT data sharing.