Practical and secure integrated PKE+PEKS with keyword privacy

Public-key encryption with keyword search (PEKS) schemes are useful to delegate searching capabilities on encrypted data to a third party, who does not hold the entire secret key, but only an appropriate token which allows searching operations but preserves data privacy. We propose an efficient and practical integrated public-key encryption (PKE) and public-key encryption with keyword search (PEKS) scheme (PKE+PEKS) which we prove to be secure in the strongest security notion for PKE+PEKS schemes. In particular, we provide a unified security proof of its joint CCA-security in standard model. The security of our scheme relies on Symmetric eXternal Diffie-Hellman (SXDH) assumption which is a much simpler and more standard hardness assumption than the ones used in most of the comparable schemes. Ours is the first construction to use asymmetric pairings which enable an extremely fast implementation useful for practical applications. Finally we compare our scheme with other proposed integrated PKE+PEKS schemes and provide a relative analysis of its efficiency.