Privacy-Preserving Phrase Search over Encrypted Data
Jiawei Hou, Yaru Liu, Rong Hao · 2021
Phrase search, as a special multi-keyword search, plays an important role in many application scenarios. It not only requires the searched keywords are consecutive, but also the location relation of searched keywords is fixed. To save local storage, more and more data owners would like to outsource their data to the cloud server. In order to ensure data security and user privacy, data is generally stored on the cloud server in encrypted form. Unfortunately, encrypted data will lose the ability of being directly searched. In order to address the problem, Searchable Symmetric Encryption (SSE) technology came into being. Most of existing phrase search SSE schemes require two rounds of interaction between the user side and the cloud server or a trusted third party or disclose location information to cloud server. In this paper, we present a phrase search SSE scheme that supports dynamic update. Our scheme only needs single round interaction between the user and the cloud server, and the location information cannot be revealed. Our scheme exploits Virtual Binary Tree (VBTree), which is only a logical structure used to store keywords. In actual storage, elements of each leaf node are stored in the hash table and non-leaf node is mapped to the bloom filter. In order to determine the location relation of searched keywords, our scheme utilizes homomorphic encryption and bilinear map. In this way, the location information cannot be revealed.