Public-Key Encryption With Keyword Search via Obfuscation

Public-key encryption with keyword search (PEKS) enables users to search on encrypted data, which is applicable to the scenario of sharing data in the cloud storage. In this paper, we focus on how to construct a PEKS scheme via obfuscation. Our basic scheme is built on the differing-inputs obfuscation (diO) and can be considered as an initial attempt to apply diO in the PEKS field. The scheme supports searching on encrypted data by providing to the cloud server an obfuscated simple "decrypt-then-compare" circuit with the secret key and the queried keyword hardwired in it. More interestingly, the scheme can be simply improved to resist off-line keyword guessing attacks (KGAs) as the standard PEKS scheme rather than a designated tester one. For complex search conditions, our scheme can be easily extended to multiple functionalities, such as conjunctive and fuzzy keyword search. Furthermore, it can be extended to the PEKS scheme in the multi-user setting.