Paper 2025/063

Enabling Puncturable Encrypted Search over Lattice for Privacy-Preserving in Mobile Cloud

Abstract

Searchable encryption (SE) has been widely studied for mobile cloud computing, allowing data encrypted search. However, existing SE schemes cannot support the fine-grained searchability revocation. Puncturable encryption (PE) can revoke the decryption ability for a specific message, which can potentially alleviate this issue. Moreover, the threat of quantum computing remains an important concern, leading to privacy leakage in the mobile cloud. Consequently, designing a post-quantum puncturable encrypted search scheme is still far-reaching. In this paper, we propose PunSearch, the first puncturable encrypted search scheme over lattice for data privacy-preserving in mobile cloud. PunSearch provides a fine-grained searchability revocation while enjoying quantum safety. Different from existing PE schemes, we construct a novel trapdoor generation mechanism through evaluation algorithms and pre-image sampling technique. We then design a search permission verification method to revoke the searchability for specific keywords. Furthermore, we formulate a new IND-Pun-CKA model and utilize it to analyze the security of PunSearch. Comprehensive performance evaluation indicates that the computational overheads of Encrypt, Trapdoor, Search, and Puncture algorithms in PunSearch are just 0.064, 0.005, 0.050, and 0.311 times of other prior arts, respectively under the best cases. These results demonstrate that PunSearch is effective and secure in mobile cloud computing.