DescriptionHALO is a decentralized oracle solution that can provide a complete data solution for any smart contract on blockchain. It adopts a node ecological mechanism of quotation and dual-role verification. Any user can pledge HALO tokens with a low threshold to become a quotation node and obtain mining rewards. The high-threshold ordinary verification nodes and the institutional verification nodes which are appointed by the HALO community can provide the ultimate security guarantee for the entire network in the verification and arbitration process. This mechanism takes into account both decentralization and anti-attack.