FTPS: Efficient fault-tolerant dynamic phrase search over outsourced encrypted data with forward and backward privacy.

With the popularity of cloud computing, more and more users store sensitive information in cloud servers. In order to protect the data over the cloud server, symmetric encryption with keyword search has been developed and the phrase search has been proposed subsequently to overcome the inefficiency produced by single/multi-keyword search. However, most existing phrase search schemes fails to support fault-tolerant search which is essential to users. Therefore, this paper proposes a fault-tolerant dynamic phrase search scheme with forward privacy and backward privacy (FTPS). Piecewise Linear Chaotic Map and minhash function are used to blur information, and Bloom filter based index is constructed to realize efficient search and dynamic update simultaneously. Security analysis proves that FTPS can properly preserve the privacy of search user, and experimental results show that FTPS is practical.