  As a trusted middleware connecting the blockchain and the real world, the
blockchain oracle can obtain trusted real-time price information for financial
applications such as payment and settlement, and asset valuation on the
blockchain. However, the current oracle schemes face the dilemma of security
and service quality in the process of node selection, and the implicit interest
relationship in financial applications leads to a significant conflict of
interest between the task publisher and the executor, which reduces the
participation enthusiasm of both parties and system security. Therefore, this
paper proposes an anonymous node selection scheme that anonymously selects
nodes with high reputations to participate in tasks to ensure the security and
service quality of nodes. Then, this paper also details the interest
requirements and behavioral motives of all parties in the payment settlement
and asset valuation scenarios. Under the assumption of rational participants,
an incentive mechanism based on the Stackelberg game is proposed. It can
achieve equilibrium under the pursuit of the interests of task publishers and
executors, thereby ensuring the interests of all types of users and improving
the enthusiasm of participation. Finally, we verify the security of the
proposed scheme through security analysis. The experimental results show that
the proposed scheme can reduce the variance of obtaining price data by about
55\% while ensuring security, and meeting the interests of all parties.
