Ranked Searchable Symmetric Encryption Supporting Conjunctive Queries

Searchable symmetric encryption allows searching over the encrypted data directly without decryption, which is particularly useful in cloud computing as users can outsource the data to cloud servers without privacy leakage while retaining the ability to search. To meet users' specific needs, searching supporting conjunctive queries and ranking is considered. Based on the searchable symmetric encryption protocol OXT of Cash et al., we propose a ranked searchable symmetric encryption scheme by integrating order preserving encryption, so that the matching documents returned to the client are ordered by keyword occurrences. It retains OXT's efficiency and supports ranked search. The security analysis shows that the proposed scheme is secure against chosen plaintext attacks.