Sequence based searching over encrypted outsourced XML data

Abstract

There has been a considerable interest for securely querying XML data stored on a remote untrusted database server over insecure channels. In order to protect confidential XML data from malicious uses, XML data should be encrypted. Once XML data has been encrypted, querying it without revealing its content to untrusted server becomes a major research of area. Brinkman et al. introduced a way to search for simple path queries over encrypted XML data. Their proposal does not scale well for structural queries and has some drawbacks due to redundancy in XML format. In this thesis, we propose a new secure outsourcing scheme for XML documents which uses Prufer Indexes for Indexing XML (PRIX) system. OPES is an encryption technique, which preserves natural order of data. We propose an algorithm to an swer range queries over encrypted XML data using OPES. We have implemented our scheme using PRIX as a basis. We compare our scheme with previous works in Secure Data Outsourcing of XML documents. Experiments show a major improvement in path queries, and very good query processing times for structural queries. Total time required to encrypt documents is also substantially reduced.