Secure Boolean Queries over Encrypted Data from Indistinguishability Obfuscation

Searchable symmetric encryption (SSE) is a practical technique that allows a client to outsource her encrypted files while maintaining an efficient and secure keyword search ability to authorized clients. To support multi-keyword or Boolean search capability, most of the existing SSE designs inevitably reveal the intermediate single keyword search result to the remote server. Such unintended leakage could be abused to infer the valuable information of the encrypted dataset. In order to hide this kind of intermediate search result (even in some private manners), two promising directions could be adopted, one is a hardware-assisted technology, e.g., Intel SGX, and the other is a software-based approach, e.g., indistinguishability obfuscation (iO). Here, we focus on the iO approach and devise a highly-scalable SSE design for supporting Boolean queries without revealing its single keyword search results. To show the advantages of our proposed design, we conduct a theoretical comparison between some related SSE protocols and ours in terms of storage and computation costs.