Paper 2019/1418

Quantum-resistant Designated-ciphertext Searchable Encryption

Zi-Yuan Liu and Yi-Fan Tseng and Raylin Tso

Abstract

Public key encryption with keyword search (PEKS) was proposed by Boneh et al. in 2004; it allows users to search encrypted keywords without losing data privacy. Although extensive studies have been conducted on this topic, only a few focus on the insider keyword guessing attack that will cause users to leak sensitive information. More specifically, after receiving the trapdoor from the user, the malicious insider (e.g. server) can randomly encrypt possible keywords using the user's public key. Then, the insider can test whether the trapdoor corresponds to the selected keyword. To solve the above issue, we introduce the notion of designated-ciphertext searchable encryption (DCSE) in this work. Then, we propose a generic construction that employs an anonymous identity-based encryption and key encapsulation mechanism. Additionally, we demonstrated that our work satisfies the indistinguishability under chosen-keyword attack (IND-CKA) and indistinguishability under insider keyword guessing attack (IND-IKGA) in the standard model. Moreover, we provide an instantiation from the NTRU lattices. Compared with other state-of-the-art schemes, our scheme is not only more efficient and practical, it also provides more robust security.