Analysis and Improvement of a Verifiable Phrase Search over Encrypted Data in a Single Phrase

Z. A. Kissel proposed a verifiable single-phase phrase search scheme using symmetric encryption algorithm, which was proved non-adaptively secure in the Semi-Honestbut-Curious (SHBC) model. We present a security analysis of Z. A. Kissel´s scheme and show that the cloud service provider can obtain some new phrases´ trapdoors and search outcomes based on the client´s a phrase query. Additionally, we propose an improvement to simplify Kissel´s scheme and enhance its security.