Searchable encryption algorithm based on key aggregation of multiple data owners in data sharing

Abstract

Searchable encryption allows data owners to outsource their encrypted data to cloud servers and provide a searchable encryption service without exposing their sensitive information. Existing searchable encryption schemes provide the service for users to query the encrypted data of a single data owner. However, these schemes ignore the problem of query matching efficiency when users query the encrypted data of multiple data owners simultaneously. Specifically, for the same content encrypted by different data owners, users need to generate different query trapdoors in the query phase and match the different query trapdoors and indexes in the matching phase. In this paper, we propose a searchable encryption algorithm based on the key aggregation of multiple data owners. The algorithm first generates keys for multiple data owners using the mutual inversion of elements in a finite field to ensure the consistency of ciphertext processing. Then, it generates index keys to build encrypted indexes and ensure the searchability of the ciphertext. Finally, it generates query trapdoors based on multi-key aggregation to match the encrypted indexes of multiple data owners. The theoretical analysis and simulation results show that the proposed algorithm improves the query efficiency and protects the query indexes and trapdoors.