Hybrid Smart Contracts for Privacy-Preserving-Aware Insurance Compensation

Large-scale applications of electronic medical records (EHRs) based on blockchain technology have prompted us to find an intelligent way to realize insurance compensation, which brings convenience for both insurance companies and patients. However, due to the public verifiability of blockchains, straightforward utilizing a blockchain to construct an insurance compensation scheme would cause leakage of patients' privacy. In this paper, we propose an agent compensation model based on smart contract to guarantee the credibility of EHRs and to enable automatical insurance compensation without requiring interactions between insurance companies and patients. A hybrid smart contract privacy-preserving insurance compensation scheme is put forward based on the agent compensation model. The "private" and "public" smart contracts are deployed on the private and public blockchain respectively. By designing private smart contracts, we limit the visitors of private data and prevent third parties from accessing patient private data. By deploying public smart contract that introduces zero-knowledge proof and blockchain oracles, we realize compensations information verification and agent payment without privacy data leakage. Security analysis and performance evaluations are conducted to prove that our scheme is secure against various attacks while achieving high efficiency.