A fast and accurate multi-keyword sorted searchable scheme based on blockchain

Abstract

The multi-keyword sorted searchable encryption is a practical and secure data processing technique. However, most of the existing schemes require each data owner to calculate and store the Inverse Document Frequency (IDF) value, and then dynamically summarize them into a global IDF value. This not only hinders efficient sharing of massive data but also may cause privacy disclosure. Additionally, using a cloud server as storage and computing center can compromise file integrity and create a single point of failure. To address these challenges, our proposal leverages the complex interactive environment and massive data scenarios of the supply chain to introduce a fast and accurate multi-keyword search scheme based on blockchain technology. Specifically, encrypted files are first stored in an Interplanetary File System (IPFS), while secure indexes are stored in a blockchain to eliminate single points of failure. Moreover, we employ homomorphic encryption algorithms to design a blockchain-based index tree that enables dynamic adaptive calculation of IDF values, dynamic update of indexes, and multi-keyword sorting search capabilities. Notably, we have specifically designed a two-round sorting search mode called “Match Sort + Score Sort” for achieving fast and accurate searching performance. Furthermore, fair payment contracts have been implemented on the blockchain to incentivize data sharing activities. Through rigorous safety analysis and comprehensive performance evaluation tests, our scheme has been proven effective as well as practical.