On the Security of a Certificateless Searchable Public Key Encryption Scheme

Searchable public key encryption is a cryptographic mechanism which provides an efficient way to search an encrypted keyword. In this paper, we show that Peng et al.'s certificateless searchable public key encryption scheme suffered from a malicious PKG attack and an off-line keyword guessing attack. In the first attack, a malicious PKG can obtain a part of an authorized receiver's private key. In the second attack, the malicious PKG can guess a keyword related to the authorized receiver's trapdoor using the part of receiver's private.