Dynamic Searchable Symmetric Encryption With Strong Security and Robustness

Dynamic Searchable Symmetric Encryption (DSSE) is a prospective technique in the field of cloud storage for secure search over encrypted data. A DSSE client can issue update queries to an honest-but-curious server for adding or deleting his ciphertexts to or from the server and delegate keyword search over those ciphertexts to the server. Numerous investigations focus on achieving strong security, like forward-and-Type-I--backward security, to reduce the information leakage of DSSE to the server as much as possible. However, the existing DSSE with such strong security cannot keep search correctness and stable security (or robustness, in short) if irrational queries are issued by the client, like duplicate add or delete queries and the delete queries for removing non-existed entries, to the server unintentionally. Hence, this work proposes two new DSSE schemes, named SR-DSSEa and SR-DSSEb , respectively. Both two schemes achieve forward-and-Type-I--backward security while keeping robustness when irrational queries are issued. In terms of performance, SR-DSSEa has more efficient communication costs and roundtrips than SR-DSSEb . In contrast, SR-DSSEb has a more efficient search performance than SR-DSSEa . Its search performance is close to the existing DSSE scheme with the same security but fails to achieve robustness.