Method of Interaction between Blockchain and the World outside the Chain based on Oracle Machine

Abstract

Blockchain is a decentralized distributed ledger where data is produced and stored in units of blocks, and is connected end to end in chronological order to form a chain structure. However, at present, the blockchain has a certain degree of closure, that is, the problem of interaction between the blockchain and the outside of the chain, and the blockchain cannot access the state of the external closed world system. In order to overcome this limitation, various platforms have introduced the concept of oracles in different forms and purposes. However, so far, there is still a lack of elaboration on the classification, analysis and research of basic Oracle methods. Based on the two basic perspectives of Oracle, this article studies and expresses the basic Oracle model of the blockchain to solve the following problems: From the perspective of the blockchain, the data flow is divided into inbound data flow and outbound data flow; From the perspective of the originator of the data flow, the communication direction is divided into push-based communication and pull-based communication. This paper describes the structural design of these four methods in detail, which can provide researchers with some method inspiration and design ideas for the interaction between the blockchain and the off-chain world.