A Low Storage Phase Search Scheme Based on Bloom Filters for Encrypted Cloud Services

Despite the many benefits of cloud technologies, there have also been significant concerns regarding its security and privacy. To address the issues, much efforts have been made towards development of an encrypted cloud system. One of the key features being investigated is the ability to search over encrypted data. Although many have proposed solutions for conjunctive keyword search, few have considered phrase searching techniques over encrypted data. Due to the increased amount of information required to identify phrases, existing phrase search algorithms require significantly more storage than conjunctive keyword search schemes. In this paper, we propose a phrase search scheme, which takes advantage of the space efficiency of Bloom filters, for applications requiring a low storage cost. It makes use of symmetric encryption, which provides computational and storage efficiency over schemes based on public key encryption. The scheme provides simple ranking capability, can be adapted to non-keyword search and is suitable against inclusion-relation attack.