Response-Hiding and Volume-Hiding Verifiable Searchable Encryption With Conjunctive Keyword Search

Abstract

Verifiable searchable encryption (VSE) not only allows the client to search encrypted data, but also allows the client to verify whether the server honestly executes search operations. Currently, VSE scheme has been widely studied in cloud storage. However, most existing VSE schemes did not hide the access pattern and volume pattern, which respectively refer to the document identifiers and the number of documents matching the queried keywords. Recent studies have exploited these two patterns to launch attacks on searchable encryption schemes, resulting in compromising the confidentiality of encrypted data and queried keywords. In order to solve above issues, we utilize additively symmetric homomorphic encryption scheme and private set intersection protocol to construct a VSE scheme that supports conjunctive keyword search and hides the access pattern and volume pattern (i.e., response-hiding and volume-hiding). Our security model assumes that the server is malicious in the sense that it might deliberately carry out incorrect search operations. Formal security analysis demonstrates that our scheme achieves the desired security properties under our leakage function. Compared to previous schemes, our scheme has advantages in terms of performance and functionality. In an experimental setup with a security parameter of 128 bits and $2^{23}$ keyword/document pairs, the search time is approximately only 7.18 seconds.