  In recent years, blockchain has been widely applied in the Internet of Things
(IoT). Blockchain oracle, as a bridge for data communication between blockchain
and off-chain, has also received significant attention. However, the numerous
and heterogeneous devices in the IoT pose great challenges to the efficiency
and security of data acquisition for oracles. We find that the matching
relationship between data sources and oracle nodes greatly affects the
efficiency and service quality of the entire oracle system. To address these
issues, this paper proposes a distributed and efficient oracle solution
tailored for the IoT, enabling fast acquisition of real-time off-chain data.
Specifically, we first design a distributed oracle architecture that combines
both Trusted Execution Environment (TEE) devices and ordinary devices to
improve system scalability, considering the heterogeneity of IoT devices.
Secondly, based on the trusted node information provided by TEE, we determine
the matching relationship between nodes and data sources, assigning appropriate
nodes for tasks to enhance system efficiency. Through simulation experiments,
our proposed solution has been shown to effectively improve the efficiency and
service quality of the system, reducing the average response time by
approximately 9.92\% compared to conventional approaches.
