A new public key encryption with temporary keyword search

The public key encryption with keyword search (PEKS) scheme recently proposed by Boneh et al enables one to search encrypted keywords without compromising the security of the original data. In Joonsang´s paper, they proposed a important issue of refreshing keyword in PEKS. In view of the server may memorize trapdoor and reveal something about the keyword, we divide the time into several time zone using the technology of key insulted and forward security, and generate a temporary trapdoor corresponding to different time. Through this method, we solve the above problem. And our scheme is more practical in application.