Structured queries with generalized pattern matching on encrypted cloud data

To protect the privacy of cloud data, searchable encryption is proved to be an important technique since it enables cloud users to search on encrypted data. Existing solutions for searchable encryption mainly focus on some basic search functions such as boolean search, similarity search or limited wildcard-based search. They cannot properly support the advanced search type: structured queries with generalized pattern matching (such as SQL-like queries) which is widely used for information retrieval in cloud database. In this paper, we propose a new searchable encryption scheme that realizes Structured queries with generalized Pattern matching to Search over Encrypted cloud data (SPSE). In particular, SPSE allows users to conduct generalized pattern matching queries on textual attribute values of structured data, and joint them with logical operators (AND, OR, NOT) to search over multiple attributes of the data sets. Besides the improvement of search functionalities, SPSE enhances the privacy by introducing two-tier encryption structure for data confidentiality and by hiding the search pattern of attribute fields to resist statistic analysis from untrusted parties. Security analysis proves that SPSE is KPA-secure. Experiments over real data sets show that SPSE achieves high search accuracy and practical search efficiency.