SDFS: A Scalable Data Feed Service for Smart Contracts

Smart Contract (SC) is distributed, trustless, programmable, and tamper-resistant, which can realize secure and efficient information exchange, value transfer and asset management. However, SCs can only access data on their own blockchains (BCs), and can't get external information by themselves. Data feed service is a third-party data source provider that supports a broad range of data requests will thus be critical to SC ecosystems. In this paper, we propose a novel scalable data feed service for SCs, SDFS, that not only ensures that the data acquisition process is reasonable, but also guarantees that the system service is scalable. In addition, we also designed a reputation evaluation strategy for nodes to determine whether each node is a malicious node. After each feedback, the reputation value of each node will be updated. Besides that, SDFS keeps content providers auditable by using BC to preserve evidence of data processing processes. As a data feed service for SCs, it can provide the data of off-chain into the BC truly and accurately, so as to ensure the authenticity of the data on the BC and realize the SC to interact with the outside world.