Generic constructions of secure‐channel free searchable encryption with adaptive security

For searching keywords against encrypted data, public key encryption scheme with keyword search (PEKS), and its extension secure‐channel free PEKS (SCF‐PEKS), has been proposed. In this paper, we extend the security of SCF‐PEKS, calling it adaptive SCF‐PEKS, wherein an adversary (modeled as a “malicious‐but‐legitimate” receiver) is allowed to issue test queries adaptively. We show that adaptive SCF‐PEKS can be generically constructed by anonymous identity‐based encryption only. That is, SCF‐PEKS can be constructed without any additional cryptographic primitive when compared with the Abdalla et al. PEKS construction (J. Cryptology 2008), even though adaptive SCF‐PEKS requires additional functionalities. We also propose other adaptive SCF‐PEKS construction, which is not fully generic but is efficient compared with the first one. Finally, we instantiate an adaptive SCF‐PEKS scheme (via our second construction) that achieves a similar level of efficiency for the costs of the test procedure and encryption, compared with the (non‐adaptive secure) SCF‐PEKS scheme by Fang et al. (CANS2009). Copyright © 2014 John Wiley & Sons, Ltd.