A Signature-based Data Authentication Method with Bitmap-based Transformed Datain Database Outsourcing

Abstract

Abstract Due to the advancement in cloud computing technology, the research on database outsourcing has been actively done. In database outsourcing, because a service provider might be untrusted or compromised, two issues of data security emerge: data confidentiality and data integrity. Many data transformation schemes were widely studied for preserving data confidentiality, but they are vulnerable to data leakage problem because they do not consider data distribution when encrypting original data. Meanwhile, several query authentication schemes were proposed to verity data integrity, but they suffer from transmission overhead of verification data. In this paper, we propose a privacy-aware data transformation and a query authentication scheme which guarantees the data confidentiality and the query result integrity of sensitive data. To solve the original data leakage problem, we propose a bitmap-based data transformation scheme with anchor selection based on data distribution. We also devise an algebraic coding-based hash index that transforms a query to a bitmap and retrieves the anchor information efficiently. To reduce the transmission overhead of verification data, we propose a query result authentication index that stores an encrypted signature for each anchor, which is an concatenated hash digest of cluster data. Through performance evaluation, we show that our scheme outperforms the existing method up to 15 times, in terms of query processing time and verification overhead.