Computational issues connected with the protection of sensitive statistics by auditing sum-queries

Abstract

An implementation of the auditing strategy is presented to avoid both exact and approximate disclosure. The key data structure is a query map, which is a graphical summary of answered queries. Since the size of a query map may be exponential in the number of answered queries, a query-restriction criterion is introduced to make every query map a graph. An auditing procedure on such a graph is presented and the computational issues connected with its implementation are discussed. All the computational tasks can be carried out efficiently but one, which is a provably intractable problem.