Pairing-Free Searchable Encryption for Enhancing Security Against Frequency Analysis Attacks

With the rapid development of cloud technology, a growing volume of encrypted data is being stored on cloud servers. Public key searchable encryption (PEKS) has emerged as a solution to the challenge of retrieving encrypted data. However, most PEKS schemes are vulnerable to frequency analysis attacks (FAA), which can potentially expose sensitive information. To address this issue, we propose a pairing-free public key searchable encryption scheme that is specifically designed to resist such attacks. Our scheme is built upon the decisional Diffie–Hellman (DDH) assumption, and effectively mitigates the risk of malicious adversaries extracting keyword information through trapdoor search frequencies. The pairing-free nature of our approach not only enhances the security against FAA but also improves the retrieval efficiency compared to traditional PEKS schemes. We formally prove that our scheme satisfies both chosen keyword attack (CKA) security and keyword guessing attack (KGA) security. Additionally, we perform comprehensive theoretical and experimental evaluations to assess the scheme’s efficiency, showcasing its practical applicability in real-world scenarios.