Trapdoor-indistinguishable Secure Channel Free Public Key Encryption with Multi-Keywords Search (Student Contributions)

Abstract

Public Key Encryption with Keyword Search (PEKS) enables users to search encrypted messages by a specific keyword without compromising the original data security. Traditional PEKS schemes allow users to search one keyword only instead of multiple keywords. Therefore, these schemes may not be applied in practice. Besides, some PEKS schemes are vulnerable to Keyword Guessing Attack (KGA). This paper formally defines a concept of Trapdoor-indistinguishable Secure Channel Free Public Key Encryption with Multi-Keywords Search (tSCF-MPEKS) and then presents a concrete construction of tSCF-MPEKS. The proposed scheme solves multiple keywords search problem and satisfies the properties of Ciphertext Indistinguishability and Trapdoor Indistinguishability. Its security is semantic security in the random oracle models under Bilinear Diffle-Hellman (BDH) and 1-Bilinear Diffie-Hellman Inversion (1-BDHI) assumptions so that it is able to resist KGA.