关键词: 保险交易；区块链技术；保单区块存储员；区块规模

Abstract: Considering that the integration of blockchain technology and social economy is an irresistible trend, the insurance industry is identified as an important application because of the natural fit of its characteristics and blockchain technology. The insurance transaction process is analyzed based on blockchain technology and constructs a static optimal blockchain model based on the insurance transactions. The following conclusions can be drawn: First, a qualitative analysis shows that the key to applying blockchain technology to insurance is to build an insurance blockchain, that is, to record insurance transactions in the ledger according to certain rules. The follow-up procedures such as reinsurance, surrender, and claim can be automatically realized by updating the digital identity of the subject and object of insurance in the blockchain system with the help of big data system. Second, in the insurance blockchain system, the optimal mining capacity and mining costs can be derived by maximizing the net surplus of honest miners. Concurrently, by calculating the maximum default benefit of the policyholders and insurers, and the optimal mining capacity of the dishonest miners, constraint conditions limiting the bifurcations of blockchain default can be obtained, and the static optimal blockchain model based on insurance transactions can be constructed. Third, the numerical simulation is based on China’s auto insurance business data and interviews from experts. In the benchmark parameter setting, the optimal results of blocksize, average recording time, average transaction fees, and other indicators can be obtained. Meanwhile, the comparative static analysis shows that an increase in the number of insurance transactions, the number of policy block depositors, and the block storage time, as well as a decrease in the risk loss rate, will lead to an increase in the blocksize and a decrease in the insurance transaction recording time and insurance transaction fees, while an increase in external shocks will lead to an increase in the blocksize and a decrease in the insurance transaction recording time, but the impact on insurance transaction fees depends on the balance between the increase in the delivery incentive due to an increase in external shocks and the decrease in the delivery incentive due to restricted blocksize. Based on the research results, policy recommendations are made in terms of insurtech synergy, blockchain system design, and specific scenario practice, while also pointing out some practical problems to be solved.

Key words: insurance transaction; blockchain technology; policy block depositor; blocksize