A Classification-Based Blockchain Architecture for Smart Home with Hierarchical PoW Mechanism

Smart home, as a typical Internet of Things (IoT) application, provides people with a variety of conveniences. Unfortunately, it may suffer from security and privacy issues. Currently, blockchain theory is considered as one of the potential solutions to the IoT security problem. However, according to the rules of blockchain, it requires large storage to store distributed ledgers and undertakes long latency caused by proof of work (PoW), which cannot be performed by resource-constrained IoT devices. To address the issue, we propose a classification-based blockchain architecture with a hierarchical PoW mechanism, which can reduce the storage consumption and decrease the latency. In our architecture, we divide IoT devices into several child nodes by data classification and convert the data storage into partial network storage. Furthermore, we try to set the moderate-cost security grades (SG) to adjust the difficulty of PoW for reduction of latency. Finally, comparing the performance of our scheme with the traditional method and current technology, the proposed architecture not only takes up less storage (i.e., almost 90% reduction) but also increases efficiency (i.e., almost 50% running time saving) while ensuring safety.