Certificateless Public Key Authenticated Encryption with Keyword Search Achieving Stronger Security

Transforming data into ciphertexts and storing them in the cloud database is a secure way to simplify management. Public key encryption with keyword search (PEKS) an important cryptographic primitive as it provides ability for desired files among ciphertexts. As variant of PEKS, certificateless public authenticated (CLPAEKS) not only simplifies certificate management but also could resist guessing attacks (KGA). In this paper, we analyze security models two recent CLPAEKS schemes find that they ignore threat that, upon capturing trapdoors, adversary directly compare distinguish whether are generated using same keyword. To cope threat, propose improved model define notion strong trapdoor indistinguishability. We then new scheme prove be under based on intractability DBDH problem DDH targeted bilinear group.