Verifiable conjunctive searchable symmetric encryption with result pattern hiding

Symmetric Searchable Encryption (SSE) guarantees the security of outsourced data without sacrificing search capability. Supporting conjunctive multi-keyword search makes the SSE more practical. However, existing conjunctive SSE schemes commonly face two issues: leaking the Keyword Pair Result Pattern (KPRP) and works only when the server is honest. This paper presents the first Verifiable Conjunctive Searchable Symmetric Encryption (VCSSE) without the KPRP leakage. Our approach considers any VSSE scheme as a black box and deploys a customized iteration of the recent Result-Hiding Filter, referred to as the Verifiable Result-Hiding Filter, to develop a VCSSE that prevents the disclosure of KPRP. In addition to successfully integrating both verifiability and KPRP-hiding, our scheme also avoids non-negligible false positives, in contrast to approaches that deploy the Bloom Filter. Furthermore, we introduce an extension to our solution that supports dynamic databases. In addition to the aforementioned security properties, our approach achieves forward privacy and backward privacy in dynamic settings, while also ensuring fault-tolerance for verifiability. This implies that our scheme remains resilient to incorrect updates originating from incautious clients in the malicious server setting. While ensuring all the mentioned security properties, our schemes deliver optimal sublinear complexity performance.

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