Abstract: Public key encryption with keyword search (PEKS) is a promise cryptography technique in cloud storage which not only can ensure the privacy of stored data but also has search function. In order to resist internal off-line keyword guessing attack, the current solution is to introduce the sender’s secret key and public key to make the keyword ciphertext to realize authentication function. But in these schemes, the receiver must delegate the sender in advance. This situation does not meet the actual requirements that the receiver does not want to delegate the sender. In order to satisfy these applications, we propose an efficient PEKS scheme and prove its security in the standard model. Our PEKS scheme achieves three advantages: Firstly, by introducing the identity of the sender and the server, our scheme can resist the internal and external off-line keyword guessing attack. Furthermore, the scheme doesn’t need to delegate the sender; secondly, by introducing the server’s private key and public key, the trapdoor can be transmitted by a public channel; thirdly, because anyone can verify the correctness of the keyword search ciphertext of keyword search, the scheme can resist chosen keyword ciphertext attack.

Key words: searchable encryption, keyword search, online and offline keyword guessing attacks, bilinear pairing, trapdoor