Comments on a chaos-based public key encryption with keyword search scheme

Recently, Li et al. employed chaotic maps to propose a public key encryption with keyword search scheme. The authors claimed that their scheme provides security against keyword guessing attack (KGA) performed by inside and outside adversaries. The goal of this paper is to show that this claim is not true about inside attackers. We prove that it is possible for an inside adversary to launch an attack even more severe than KGA and obtain the corresponding keyword to any searchable ciphertext. We further propose a simple fix to overcome the proposed attack.