As the certificate-based searchable encryption schemes are required to verify user′s public key and manage certificates, and most single keyword search schemes return a huge volumes of irrelevant ciphertext. And a few multi-keywords searchable schemes have to set up a quite long keywords ciphertext index. Therefore, a newly keyword search over encrypted data scheme using certificateless public key cryptosystem was proposed which can avoid public key verification and certificate management problems based on certificate cryptosystem and eliminate the key escrow problem based on identity cryptosystem. This paper employs conjunctive and multi-keywords search which gets ciphertext search more precise. Moreover, through aggregating keywords trapdoor token makes the token short and effectiv, and further getting a degree of savings in bandwidth and storage. Finally, the security analysis proved that our scheme is secure against off-line keyword guessing attack under a random oracle model.

searchable encryption; certificateless; conjunctive keywords; off-line keyword guessing attack