On security against the server in designated tester public key encryption with keyword search

The offline keyword guessing attack (KG attack) is a new security threat to the designated tester public key encryption with keyword search (dPEKS). Many techniques have been proposed to resist such an attack. However, all the schemes which are secure against KG attacks have not solved the problem that the KG attacker is the server. We redefine the security of dPEKS against KG attacks and propose IND-KGA-SERVER security. Then based on the existence of the Certificate Authority of the Public Key Infrastructure and the deterministic digital signature, we demonstrate how to construct secure dPEKS when the KG attacker is the server. Our solution is a bootstrap from IND-KGA secure dPEKS to the one of IND-KGA-SERVER security. (C) 2015 Elsevier B.V. All rights reserved.