Blockchain-enhanced identity authentication and efficient access mechanism for power internet of things

To tackle the security vulnerabilities in identity authentication and inefficient data transmission caused by large-scale terminals and centralized architecture in the Power Internet of Things (Power IoT), this paper proposes a comprehensive security and access scheme combining blockchain, smart contracts, Merkle trees and an optimized sensor access mechanism based on active backoff and Uniform Time-Slot Scheduling (UTSS). First, an active backoff algorithm and UTSS are deployed at the sensor access layer to dynamically adjust the contention window and evenly assign transmission time slots, thus lowering data collision probability and enhancing channel utilization. Second, a Cross-Node Identity Authentication Key Agreement (CN-IKA) protocol is designed to support secure and efficient cross-node authentication without repeated verification, decreasing latency in network switching. Finally, simulation tests are carried out in complex Power Internet of Things scenarios with heterogeneous sensors, network congestion and malicious attacks. Experimental results show that the proposed scheme achieves a maximum throughput of 27 packet/s, 80% higher than the UTSS-only scheme, and shortens the full authentication time of 40,000 sensors to 25 min, a 34% reduction. In summary, the proposed scheme can effectively meet the requirements of high security, high reliability, and low latency for Power Internet of Things applications.