論文ID: 2026CIP0020
Zamani, Safkhani, and Daneshpour proposed a Secure Channel Free Verifiable Public key Encryption with Keyword Search (SCF-VPEKS) scheme (Wireless Networks, 2025). Their scheme claims resistance against keyword guessing attacks, file-injection attacks, and malicious servers. In this paper, we conduct a comprehensive security analysis of their construction. We demonstrate that the verifiability mechanism of the scheme is not effective, as a malicious server can return incorrect or manipulated search results that pass the verification procedure performed by the data user (receiver). We further show that the scheme does not satisfy the standard indistinguishability notions for searchable encryption, namely Ciphertext-Keyword Indistinguishability against Chosen Keyword Attack (CW-IND-CKA) and Trapdoor-Keyword Indistinguishability against Chosen Keyword Attack (TW-IND-CKA). Specifically, by exploiting the deterministic and algebraically separable structure of the trapdoor, an adversary can extract a keyword-independent secret component from a single trapdoor and subsequently forge valid trapdoors for arbitrary keywords. As a consequence, both challenge ciphertexts and challenge trapdoors can be distinguished with probability one in polynomial time. Our analysis indicates that these vulnerabilities arise from the core construction methodology of the scheme.
