Range Query in Blockchain-based Data Sharing Model for Electronic Medical Records

Abstract

The data sharing of electronic medical records (EMRs) has great positive significance for research on disease and epidemic prevention. Recently, blockchain-based EMRs storing and sharing schemes have brought many benefits. Nevertheless, the existing medical data sharing solutions cannot fully meet the query requirements in multi-user scenarios where data users with different identities have different needs for data usage. In this paper, we propose a block construction method for storing EMRs. We combine the characteristics of the Merkle tree and prefix dictionary tree in the block to reduce the time consumption of queries in the block. Besides, the block header is identified by four attributes, namely hospital ID, Department ID, disease type, and time period. According to the query conditions, the block where the requested data is located is quickly found. In the blockchain-based data sharing model of EMRs, data requesters with different identities can make combined queries with multiple conditions according to their own needs, and then the block and transactions in the block are located accurately. In conclusion, we are the first to build the block based on disease types and our model supports more flexible combined queries with multiple conditions.