Keeping Secrets in Possibilistic Knowledge Bases with Necessity-Valued Privacy Policies

摘要

Controlled Query Evaluation (CQE) is a logical framework for the protection of secrets in databases. In this article, we extend the CQE framework to possibilistic logic: knowledge base, a priori knowledge and privacy policy are expressed with necessity-valued formulas that represent several degrees of certainty. We present a formal security definition and analyze an appropriate controlled evaluation algorithm for this possibilistic case.