Toward Authenticated Encrypted Search With Constant Trapdoor for Mobile Cloud Systems
Gang Xu, Xinyu Fan, Shiyuan Xu, Yibo Cao, Kejia Zhang, Jiawen Kang, Dusit Niyato
Abstract
Mobile cloud computing has become widely adopted for its convenience in data storage and sharing, but it also introduces challenges related to data privacy and security. To address these issues, public key authenticated encryption with keyword search (PAEKS) has emerged as a potential solution that ensures data privacy while resisting internal keyword guessing attacks (IKGAs). Unfortunately, most existing PAEKS schemes have limited adaptability to multi-user scenarios. Specifically, in PAEKS, ciphertext generation requires the participation of users' secret keys, which results in ciphertexts being unique, even when the same keywords are encrypted by different users. Con sequently, the number of trapdoors used to match the ciphertexts grows linearly with the amount of senders. Designing an efficient PAEKS scheme for multiple users remains an open challenge. In this paper, we propose CT-PAEKS, a lattice-based PAEKS scheme with constant trapdoor for data privacy-preserving in mobile cloud computing. CT-PAEKS introduces an additional administrator, enabling the receiver to generate a unified search trapdoor for ciphertexts from multiple senders. Additionally, it allows multiple senders to generate a single ciphertext for the same keyword encryption, thus avoiding ciphertext duplication. Furthermore, CT-PAEKS supports fast search during ciphertext matching, allowing all corresponding ciphertexts to be identified with a single match. We also formalize and prove the security of CT-PAEKS in the random oracle model. Comprehensive perfor mance evaluations indicate that our scheme outperforms prior arts, achieving the 1.7×-2.7× and 2.0×-4.4× reduction in terms of computational and communication overhead, respectively.