<p>To deal with the challenge of reliable sensor data delivery from the Intenet of things (IoT) to the blockchain, we presented a key assignment strategy for reliable sensor data delivery based on blockchain oracle (BO-RSDD-KAS). We formulated a key assignment mechanism based on key level, and it evaluated location closeness, data transfer rate, and temporal mobility, enhancing the network interconnection and security against sensor capture. We set up a framework of key assignment of edge network sensor based on blockchain oracle. Using sensor key and digital signature validation, validated sensors could move freely enter and exit the sub-network. We validated the presented approach against double-spending and man-in-the-middle attacks via a cybersecurity evaluation. In resource-limited scenario, including power-saving and bandwidth-limited, the presented approach decreased the reliable sensor data delivery latency and the key assignment mechanism overheads. Blockchain oracles ensured reliable sensor data delivery from IoT devices to the blockchain by providing trustworthy key assignment information, optimizing key assignment strategies, verifying sensor identities, enhancing network security, and optimizing performance in resource-constrained scenarios.</p>