Toward Practical Searchable Symmetric Encryption

Abstract

Searchable symmetric encryption is a good building block toward ensuring privacy preserving keyword searches in a cloud computing environment. This area has recently attracted a great deal of attention and a large quantity of research has been conducted. A security protocol generally faces a trade-off between security/privacy requirements and efficiency. Existing works aim to achieve the highest levels of security requirements, so they also come with high overhead. In this paper, we reconsider the security/privacy requirements for searchable symmetric encryption and relax the requirements for practical use. Then, we propose schemes suitable for the new requirements. We also show experimental results of our schemes and comparison to existing schemes. The results show that the index sizes of our proposals are only a few times of that of a Lucene (without encryption). In document update, our proposal requests additional index which depends only on the size of new document.