Searchable symmetric encryption capable of searching for an arbitrary string

Abstract

A booming cloud service has made it possible to consider a third-party server as private storage. When storage is used as a document archive, it is useful to provide functionality that allows users to find documents containing a specified string as a substring. The current method for providing such functionality while keeping the contents of the documents secret, either has linear complexity in the total size of the documents or needs to extract keywords when the documents are stored. Therefore, no method exists for efficiently searching for an arbitrary string that has not been extracted as a keyword. We propose the first encryption scheme that enables efficient searching for an arbitrary string. Although our scheme leaks some information for the sake of efficiency, all information leaked is derived from the precise leakage profile we have defined. © 2016 The Authors Security and Communication Networks Published by John Wiley & Sons Ltd.