Information Leakage Games: Exploring Information as a Utility Function. (arXiv:2012.12060v2 [cs.CR] UPDATED)

A common goal in the areas of secure information flow and privacy is to build
effective defenses against unwanted leakage of information. To this end, one
must be able to reason about potential attacks and their interplay with
possible defenses. In this paper, we propose a game-theoretic framework to
formalize strategies of attacker and defender in the context of information
leakage, and provide a basis for developing optimal defense methods. A novelty
of our games is that their utility is given by information leakage, which in
some cases may behave in a non-linear way. This causes a significant deviation
from classic game theory, in which utility functions are linear with respect to
players’ strategies. Hence, a key contribution of this paper is the
establishment of the foundations of information leakage games. We consider two
kinds of games, depending on the notion of leakage considered. The first kind,
the QIF-games, is tailored for the theory of quantitative information flow
(QIF). The second one, the DP-games, corresponds to differential privacy (DP).