Extending SQL to Support Privacy Policies

Abstract

Increasing concerns over Internet applications that violate user privacy by exploiting (back-end) database vulnerabilities must be addressed to protect both customer privacy and to ensure corporate strategic assets remain trustworthy. This chapter describes an extension onto database catalogues and Structured Query Language (SQL) for supporting privacy in Internet applications, such as in social networks, e-health, e-governmcnt, etc. The idea is to introduce new predicates to SQL commands to capture common privacy requirements, such as purpose, visibility, generalization, and retention for both mandatory and discretionary access control policies. The contribution is that corporations, when creating the underlying databases, will be able to define what their mandatory privacy policies arc with which all application users have to comply. Furthermore, each application user, when providing their own data, will be able to define their own privacy policies with which other users have to comply. The extension is supported with underlying catalogues and algorithms. The experiments demonstrate a very reasonable overhead for the extension. The result is a low-cost mechanism to create new systems that arc privacy aware and also to transform legacy databases to their privacy-preserving equivalents. Although the examples arc from social networks, one can apply the results to data security and user privacy of other enterprises as well.