## 1 Introduction  
In the present digital era, numerous economic and social activities involve multi-party interactions, such as online marketplaces, supply chain management, and the Internet of Things. In these multi-party interaction scenarios, the lack of trust between participants (such as buyers, sellers, suppliers, consumers, etc.) is aggravated because they may experience problems such as information asymmetry, fraud, false evaluation, etc. These problems can affect the security and efficiency of transactions and reduce the confidence and enthusiasm of participants. Since different participants may not be directly connected to each other, specific mechanisms are needed to establish and maintain trust relationships to ensure the safety and effectiveness of the interaction process. It is challenging to guarantee trust in multi-party interaction scenarios, and one of the main reasons is the lack of an effective supervision mechanism. There is usually no authoritative third-party organization to supervise and manage participants, which makes it difficult to establish an effective trust mechanism between participants. With the emergence of blockchain and smart contract (SC) technologies, people have begun to explore the use of these technologies to solve the trust problem in multi-partyinteraction scenarios. Blockchain is a decentralized, distributed ledger technology that can record various types of transaction information [1]. An SC is an automatically executed computer program that can define and enforce rules and terms between two or more parties [2]. Blockchain and SC technologies have the advantages of non-tampering, transparency, decentralization, and autonomy, so they are considered powerful tools to build reliable trust mechanisms. Therefore, SCs can be used to solve trust problems in different domains involving multi-party interaction scenarios, such as financial transactions, supply chains, and legal contracts. At present, SC is being increasingly widely used as the key technology in blockchain to solve the problem of the lack of trust. Various types of platforms support the development of SCs, such as Ethereum and Hyperledger Fabric [3]. The insurance industry faces trust problems, and the emergence of blockchain and SC technology provides a solution to this. The process of purchasing flight delay insurance and obtaining compensation is illustrated in Figure 1. In a real-life scenario, users may purchase airline tickets from airlines and potentially purchase flight delay insurance from insurance companies. The Civil Aviation Authority (CAA) is responsible for formulating flight departure plans and recording the actual takeoff and landing times of flights. If users encounter flight delays or cancellations after purchasing flight delay insurance, they can file a claim with the insurance company. Users need to provide relevant supporting documents, such as tickets, flight delay notifications, and actual departure and landing times. The insurance company will assess the legitimacy of the claim based on the terms of the contract and the claim requirements. The claim will undergo a manual review, and, if it meets the criteria, the insurance company will provide compensation. During this process, the insurance company's review time may be lengthy, and there is a possibility that they will deceive the user. If the insurance company denies the claim, the user may need to file a lawsuit against the insurance company in court, to ensure that their rights are protected. This process can be time-consuming and requires a significant amount of effort. The emergence of blockchain technology can address the trust issues in the aforementioned context. The compensation ratios of insurance policies formulated by insurance companies are reflected in the form of SC code. The takeoff and landing times of flights are also recorded on the blockchain through a unified system managed by the Civil Aviation Authority.