Searchable Encryption with Pattern Matching for Securing Data on Cloud Server

Searchable Encryption scheme is a cryptographic tool, which helps data owner to upload his data in encrypted form to storage server and allows user to search some desired data containing some specific keyword over encrypted form. There by, curious storage server need not get any partial information about the search query and stored encrypted data. There are a lots of existing techniques of searchable encryption scheme over the years. But, the practical significance of those techniques are not up to expectation. Nevertheless, it is an important tool regarding storing the data and retrieving from cloud server. For this, the scheme is gaining more attention in recent years. Searchable encryption was practically introduced by Boneh et al., who used asymmetric searchable encryption in their scheme. There are lots of techniques of searchable encryption based on single and multiple keyword search. The multiple keyword search was first attempted by Wang et al.. However, the scheme has some drawbacks. Searchable encryption with patter obfuscation was introduced by Orencik et al.. This scheme has also some shortcomings regarding security issues. In our work, we devised a searchable encryption scheme with pattern matching algorithm for multiple keywords. The scheme is designed with less space complexity and it also provides updating ranked search. We use the property of Trie data structure to reduce both the search and space complexity. Our scheme allows the ranked search with outcomes of most relevant top ranked documents which consists of the query keyword. Because of the Trie structure property, our scheme also deals with the update operation of files or documents flexibly. To ensure the privacy of the scheme, we include the fuzzy search trapdoor and exact search trapdoor here.