2 research outputs found
A novel reconstruction attack on foreign-trade official statistics, with a Brazilian case study
In this paper we describe, formalize, implement, and experimentally evaluate
a novel transaction re-identification attack against official foreign-trade
statistics releases in Brazil. The attack's goal is to re-identify the
importers of foreign-trade transactions (by revealing the identity of the
company performing that transaction), which consequently violates those
importers' fiscal secrecy (by revealing sensitive information: the value and
volume of traded goods). We provide a mathematical formalization of this fiscal
secrecy problem using principles from the framework of quantitative information
flow (QIF), then carefully identify the main sources of imprecision in the
official data releases used as auxiliary information in the attack, and model
transaction re-construction as a linear optimization problem solvable through
integer linear programming (ILP). We show that this problem is NP-complete, and
provide a methodology to identify tractable instances. We exemplify the
feasibility of our attack by performing 2,003 transaction re-identifications
that in total amount to more than \$137M, and affect 348 Brazilian companies.
Further, since similar statistics are produced by other statistical agencies,
our attack is of broader concern.Comment: 35 page