Using different encryption schemes for secure deletion while supporting queries

Abstract

As more and more private and confidential data is stored in databases and in the wake of cloud computing services hosted by third parties, the privacyaware and secure handling of such sensitive data is important. The security of such data needs not only be guaranteed during the actual life, but also at the point where they should be deleted. However, current common database management systems to not provide the means for secure deletion. As a consequence, in this paper we propose several means to tackle this challenge by means of encryption and how to handle the resulting shortcomings with regards to still allowing queries on encrypted data. We discuss a general approach on how to combine homomorphic encryption, order preserving encryption and partial encryption as means of depersonalization, as well as their use on client-side or server-side as system extensions.