An Efficient and Verifiable Blockchain-Based Multi-Keyword Searchable Encryption Scheme

Abstract

With the popularity of cloud storage, data encryption protects user privacy but also hinders efficient data retrieval. Existing searchable encryption schemes generally suffer from low query efficiency, unverifiable results, and high leakage risks in dynamic updates. This paper proposes an efficient and verifiable multi-keyword searchable encryption scheme based on blockchain. The scheme uses Bloom filter and multiset hash to achieve result integrity verification, realizes forward security through chained index and pseudo-random function (PRF), and supports multi-keyword conjunctive query. Experimental results show that the query latency of the proposed scheme is only 2.38∼24.12 ms and the client verification latency is only 13.85∼154.63 ms in single-keyword query mode. For multikeyword queries, only one primary search address set is required regardless of the number of query keywords. The scheme performs well in query latency, verification overhead and security.